1
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Heller WT. Small-Angle Neutron Scattering Study of a Phosphatidylcholine-Phosphatidylethanolamine Mixture. ACS Omega 2023; 8:33755-33762. [PMID: 37744859 PMCID: PMC10515593 DOI: 10.1021/acsomega.3c04164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Abstract
The properties of single-component phospholipid lipid bilayers have been extensively characterized. Natural cell membranes are not so simple, consisting of a diverse mixture of lipids and proteins. While having detailed structural information on complex membranes would be useful for understanding their structure and function, experimentally characterizing such membranes at a level of detail applied to model phospholipid bilayers is challenging. Here, small-angle neutron scattering with selective deuteration was used to characterize a binary lipid mixture composed of 1,2-dimyristoyl-3-sn-glycero-phosphatidylcholine and 1,2-dimyristoyl-3-sn-glycero-phosphatidylethanolamine. The data analysis provided the area per lipid in each leaflet as well as the asymmetry of the composition of the inner and outer leaflets of the bilayer. The results provide new insight into the structure of the lipid bilayer when this lipid mixture is used to prepare vesicles.
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Affiliation(s)
- William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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2
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Fang YN, Rumyantsev AM, Neitzel AE, Liang H, Heller WT, Nealey PF, Tirrell MV, de Pablo JJ. Scattering evidence of positional charge correlations in polyelectrolyte complexes. Proc Natl Acad Sci U S A 2023; 120:e2302151120. [PMID: 37523553 PMCID: PMC10410704 DOI: 10.1073/pnas.2302151120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/30/2023] [Indexed: 08/02/2023] Open
Abstract
Polyelectrolyte complexation plays an important role in materials science and biology. The internal structure of the resultant polyelectrolyte complex (PEC) phase dictates properties such as physical state, response to external stimuli, and dynamics. Small-angle scattering experiments with X-rays and neutrons have revealed structural similarities between PECs and semidilute solutions of neutral polymers, where the total scattering function exhibits an Ornstein-Zernike form. In spite of consensus among different theoretical predictions, the existence of positional correlations between polyanion and polycation charges has not been confirmed experimentally. Here, we present small-angle neutron scattering profiles where the polycation scattering length density is matched to that of the solvent to extract positional correlations among anionic monomers. The polyanion scattering functions exhibit a peak at the inverse polymer screening radius of Coulomb interactions, q* ≈ 0.2 Å-1. This peak, attributed to Coulomb repulsions between the fragments of polyanions and their attractions to polycations, is even more pronounced in the calculated charge scattering function that quantifies positional correlations of all polymer charges within the PEC. Screening of electrostatic interactions by adding salt leads to the gradual disappearance of this correlation peak, and the scattering functions regain an Ornstein-Zernike form. Experimental scattering results are consistent with those calculated from the random phase approximation, a scaling analysis, and molecular simulations.
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Affiliation(s)
- Yan N. Fang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Artem M. Rumyantsev
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC27695
| | - Angelika E. Neitzel
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL32611
| | - Heyi Liang
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN37831
| | - Paul F. Nealey
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Matthew V. Tirrell
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
| | - Juan J. de Pablo
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL60637
- Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, IL60439
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3
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Kim M, Han MJ, Lee H, Flouda P, Bukharina D, Pierce K, Adstedt K, Buxton M, Yoon Y, Heller WT, Singamaneni S, Tsukruk VV. Bio-Templated Chiral Zeolitic Imidazolate Framework-8 for Enantioselective Chemoresistive Sensing. Angew Chem Int Ed Engl 2023:e202305646. [PMID: 37235528 DOI: 10.1002/anie.202305646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 05/28/2023]
Abstract
Chiral metal-organic frameworks (MOFs) have gained rising attention as ordered nanoporous materials for enantiomer separations, chiral catalysis, and sensing. Among those, chiral MOFs are generally obtained through complex synthetic routes by using a limited choice of reactive chiral organic precursors as the primary linkers or auxiliary ligands. Here, we report a template-controlled synthesis of chiral MOFs from achiral precursors grown on chiral nematic cellulose-derived nanostructured bio-templates. We demonstrate that chiral MOFs, specifically, zeolitic imidazolate framework-8 (ZIF-8), can be grown from regular precursors within nanoporous organized chiral nematic nanocelluloses via directed assembly on twisted bundles of cellulose nanocrystals. The template-grown chiral ZIF-8 possesses tetragonal crystal structure with chiral space group of P41, which is different from traditional cubic crystal structure of I-43m for freely grown conventional ZIF-8. The uniaxially compressed dimensions of the unit cell of templated ZIF-8 and crystalline dimensions are signatures of this structure. We observe that the templated chiral ZIF-8 can facilitate the enantiotropic sensing. It shows enantioselective recognition and chiral sensing abilities with a low limit of detection of 39 µM and the corresponding limit of chiral detection of 300 µM for representative chiral amino acid, D- and L- alanine.
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Affiliation(s)
- Minkyu Kim
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Moon J Han
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Hansol Lee
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Paraskevi Flouda
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Daria Bukharina
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Kellina Pierce
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Katarina Adstedt
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Madeline Buxton
- Georgia Institute of Technology School of Materials Science and Engineering, MSE, UNITED STATES
| | - Younghee Yoon
- Georgia Institute of Technology School of Materials Science and Engineering, ChE, UNITED STATES
| | - William T Heller
- ORNL: Oak Ridge National Laboratory, Neutron Scattering Division, UNITED STATES
| | - Srikanth Singamaneni
- Washington University In St Louis: Washington University in St Louis, MSE, UNITED STATES
| | - Vladimir V Tsukruk
- Georgia Institute of Technology, Materials Science and Engineering, 771 Ferst Dr., NW, 30332, Atlanta, UNITED STATES
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4
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Premadasa UI, Bocharova V, Lin L, Genix AC, Heller WT, Sacci RL, Ma YZ, Thiele NA, Doughty B. Tracking Molecular Transport Across Oil/Aqueous Interfaces: Insight into "Antagonistic" Binding in Solvent Extraction. J Phys Chem B 2023. [PMID: 37216432 DOI: 10.1021/acs.jpcb.3c00386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Liquid/liquid (L/L) interfaces play a key, yet poorly understood, role in a range of complex chemical phenomena where time-evolving interfacial structures and transient supramolecular assemblies act as gatekeepers to function. Here, we employ surface-specific vibrational sum frequency generation combined with neutron and X-ray scattering methods to track the transport of dioctyl phosphoric acid (DOP) and di-(2-ethylhexyl) phosphoric acid (DEHPA) ligands used in solvent extraction at buried oil/aqueous interfaces away from equilibrium. Our results show evidence for a dynamic interfacial restructuring at low ligand concentrations in contrast to expectation. These time-varying interfaces arise from the transport of sparingly soluble interfacial ligands into the neighboring aqueous phase. These results support a proposed "antagonistic" role of ligand complexation in the aqueous phase that could serve as a holdback mechanism in kinetic liquid extractions. These findings provide new insights into interfacially controlled chemical transport at L/L interfaces and how these interfaces vary chemically, structurally, and temporally in a concentration-dependent manner and present potential avenues to design selective kinetic separations.
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Affiliation(s)
- Uvinduni I Premadasa
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Vera Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lu Lin
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Anne-Caroline Genix
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, F-34095 Montpellier, France
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Robert L Sacci
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Nikki A Thiele
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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5
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Ma Y, Heil C, Nagy G, Heller WT, An Y, Jayaraman A, Bharti B. Synergistic Role of Temperature and Salinity in Aggregation of Nonionic Surfactant-Coated Silica Nanoparticles. Langmuir 2023; 39:5917-5928. [PMID: 37053432 PMCID: PMC10134496 DOI: 10.1021/acs.langmuir.3c00432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/03/2023] [Indexed: 06/19/2023]
Abstract
The adsorption of nonionic surfactants onto hydrophilic nanoparticles (NPs) is anticipated to increase their stability in aqueous medium. While nonionic surfactants show salinity- and temperature-dependent bulk phase behavior in water, the effects of these two solvent parameters on surfactant adsorption and self-assembly onto NPs are poorly understood. In this study, we combine adsorption isotherms, dispersion transmittance, and small-angle neutron scattering (SANS) to investigate the effects of salinity and temperature on the adsorption of pentaethylene glycol monododecyl ether (C12E5) surfactant on silica NPs. We find an increase in the amount of surfactant adsorbed onto the NPs with increasing temperature and salinity. Based on SANS measurements and corresponding analysis using computational reverse-engineering analysis of scattering experiments (CREASE), we show that the increase in salinity and temperature results in the aggregation of silica NPs. We further demonstrate the non-monotonic changes in viscosity for the C12E5-silica NP mixture with increasing temperature and salinity and correlate the observations to the aggregated state of NPs. The study provides a fundamental understanding of the configuration and phase transition of the surfactant-coated NPs and presents a strategy to manipulate the viscosity of such dispersion using temperature as a stimulus.
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Affiliation(s)
- Yingzhen Ma
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Christian Heil
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Gergely Nagy
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yaxin An
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Arthi Jayaraman
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Bhuvnesh Bharti
- Cain
Department of Chemical Engineering, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
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6
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Hu M, Li X, Heller WT, Bras W, Rzayev J, Russell TP. Using Grazing-Incidence Small-Angle Neutron Scattering to Study the Orientation of Block Copolymer Morphologies in Thin Films. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Mingqiu Hu
- Polymer Science and Engineering Department, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Xindi Li
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, P.O. Box 2008,
MS-6473, Oak Ridge, Tennessee 37831, United States
| | - Wim Bras
- Chemical Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6131, Oak Ridge, Tennessee 37831, United States
| | - Javid Rzayev
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Thomas P. Russell
- Polymer Science and Engineering Department, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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7
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Goswami M, Iyiola OO, Lu W, Hong K, Zolnierczuk P, Stingaciu LR, Heller WT, Taleb O, Sumpter BG, Hallinan DT. Understanding Interfacial Block Copolymer Structure and Dynamics. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c01814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Monojoy Goswami
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Oluwagbenga Oare Iyiola
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
| | - Wei Lu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-2200, United States
| | - Kunlun Hong
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-2200, United States
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Piotr Zolnierczuk
- Juelich Center for Neutron Science, Outstation at the Spallation Neutron Source, Oak Ridge, Tennessee 37831-6473, United States
| | - Laura-Roxana Stingaciu
- Neutron Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Neutron Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Omar Taleb
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Daniel T. Hallinan
- Chemical and Biomedical Engineering Department, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
- Aero-Propulsion, Mechatronics and Energy Center, Florida A&M University-Florida State University College of Engineering, Tallahassee, Florida 32310-6046, United States
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Abstract
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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9
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Abstract
Protein biomaterials offer several advantages over those made from other components because their amino acid sequence can be precisely controlled with genetic engineering to produce a diverse set of material building blocks. In this work, three different elastin-like polypeptide (ELP) sequences were designed to synthesize pH-responsive protein vesicles. ELPs undergo a thermally induced hydrophobic transition that enables self-assembly of different kinds of protein biomaterials. The transition can be tuned by the composition of the guest residue, X, within the ELP pentapeptide repeat unit, VPGXG. When the guest residue is substituted with an ionizable amino acid, such as histidine, the ELP undergoes a pH-dependent hydrophobic phase transition. We used pH-responsive ELPs with different levels of histidine substitution, in combination with leucine zippers and globular, functional proteins, to fabricate protein vesicles. We demonstrate pH-dependent self-assembly, diameter, and disassembly of the vesicles using a combination of turbidimetry, dynamic light scattering, microscopy, and small angle X-ray scattering. As the ELP transition is dependent on the sequence, the vesicle properties also depend on the histidine content in the ELP building blocks. These results demonstrate the tunability of protein vesicles endowed with pH responsiveness, which expands their potential in drug-delivery applications.
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Affiliation(s)
- Dylan R Dautel
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - William T Heller
- Neutron Scattering, Oak Ridge National Laboratory, PO Box 2008, MS 6473, Oak Ridge, Tennessee 37831, United States
| | - Julie A Champion
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States
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10
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Heller WT, Do C. Impact of Two Water-Miscible Ionic Liquids on the Temperature-Dependent Self-Assembly of the (EO) 6-(PO) 34-(EO) 6 Block Copolymer. ACS Omega 2022; 7:19474-19483. [PMID: 35721995 PMCID: PMC9202293 DOI: 10.1021/acsomega.2c01166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
There are many studies on the self-assembly of triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymers in aqueous solution. These polymers display a rich phase diagram as a function of block length, concentration, temperature, and additives. Here, we present a small-angle neutron scattering study of the impact of two water-miscible ionic liquids, 1-butyl-3-methylimidazolium chloride ([C4C1mim][Cl]) and 1-butyl-3-methylpyrrolidinium chloride ([C4C1pyrr][Cl]), on the temperature-dependent self-assembly of (EO)6-(PO)34-(EO)6, also known as L62 Pluronic, in aqueous solution. Both ionic liquids depress the temperatures of the various structural transitions that take place, but ([C4C1pyrr][Cl]) has a stronger effect. The structures that the triblock copolymer self-assembles into do not dramatically change nor do they significantly change the series of structures that the system transitions through as a function of temperature relative to the various transition temperatures.
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11
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Doucet M, Archibald RK, Heller WT. Machine learning for neutron reflectometry data analysis of two-layer thin films
*. Mach Learn : Sci Technol 2021. [DOI: 10.1088/2632-2153/abf257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Neutron reflectometry (NR) is a powerful tool for probing thin films at length scales down to nanometers. We investigated the use of a neural network to predict a two-layer thin film structure to model a given measured reflectivity curve. Application of this neural network to predict a thin film structure revealed that it was accurate and could provide an excellent starting point for traditional fitting methods. Employing prediction-guided fitting has considerable potential for more rapidly producing a result compared to the labor-intensive but commonly-used approach of trial and error searches prior to refinement. A deeper look at the stability of the predictive power of the neural network against statistical fluctuations of measured reflectivity profiles showed that the predictions are stable. We conclude that the approach presented here can provide valuable assistance to users of NR and should be further extended for use in studies of more complex n-layer thin film systems. This result also opens up the possibility of developing adaptive measurement systems in the future.
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12
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Doucet M, Samarakoon AM, Do C, Heller WT, Archibald R, Alan Tennant D, Proffen T, Granroth GE. Machine learning for neutron scattering at ORNL *. Mach Learn : Sci Technol 2021. [DOI: 10.1088/2632-2153/abcf88] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Abstract
Machine learning (ML) offers exciting new opportunities to extract more information from scattering data. At neutron scattering user facilities, ML has the potential to help accelerate scientific productivity by empowering facility users with insight into their data which has traditionally been supplied by scattering experts. Such support can help in both speeding up common modeling problems for users, as well as help solve harder problems that are normally time consuming and difficult to address with standard methods. This article explores the recent ML work undertaken at Oak Ridge National Laboratory involving neutron scattering data. We cover materials structure modeling for diffuse scattering, powder diffraction, and small-angle scattering. We also discuss how ML can help to model the response of the instrument more precisely, as well as enable quick extraction of information from neutron data. The application of super-resolution techniques to small-angle scattering and peak extraction for diffraction will be discussed.
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13
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Rother G, Tumuluri U, Huang K, Heller WT, Dai S, Carrillo JM, Sumpter BG. Interactions of an Imine Polymer with Nanoporous Silica and Carbon in Hybrid Adsorbents for Carbon Capture. Langmuir 2021; 37:4622-4631. [PMID: 33819051 DOI: 10.1021/acs.langmuir.1c00305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Efficient carbon capture from stationary point sources can be achieved using hybrid adsorbents comprising nanoporous substrates coated with imine polymers. The physical properties of the CO2-adsorbing, nanodispersed polymers are altered by their interactions with the substrate, which in turn may impact their capture capacity. We study silica and carbon nanoporous substrates with different pore morphologies that were impregnated with polymer imine with the goal of characterizing the polymer dispersions in the pores. For silica and carbon samples, the mean densities of confined poly(ethylene imine) (PEI) were measured as functions of polymer loading and temperature using small-angle neutron scattering. Strong densification is found for imine polymers imbibed in mesoporous carbon. PEI in nanoporous silica does not experience this strong densification. At high loadings, plugs form, preferably at the pore throats, and can reduce accessible porosity. CO2 capture measurements show that PEI interactions with the substrate play an important role. PEI in carbon shows the highest capture capacity at low temperatures and the lowest CO2 adsorption at high temperatures, making it well-suited for temperature swing adsorption applications.
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Affiliation(s)
- Gernot Rother
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Uma Tumuluri
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Kuan Huang
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - William T Heller
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sheng Dai
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jan-Michael Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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14
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Affiliation(s)
- Yingzhen Ma
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Lilin He
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - William A. Shelton
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
| | - Gernot Rother
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Bhuvnesh Bharti
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, USA
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15
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Tao Y, Teng C, Musho TD, van de Burgt L, Lochner E, Heller WT, Strouse GF, Dudley GB, Stiegman AE. Direct Measurement of the Selective Microwave-Induced Heating of Agglomerates of Dipolar Molecules: The Origin of and Parameters Controlling a Microwave Specific Superheating Effect. J Phys Chem B 2021; 125:2146-2156. [PMID: 33605727 DOI: 10.1021/acs.jpcb.0c10291] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Agglomerates of polar molecules in nonpolar solvents are selectively heated by microwave radiation. The magnitude of the selective heating was directly measured by using the temperature dependence of the intensities of the Stokes and anti-Stokes bands in the Raman spectra of p-nitroanisole (pNA) and mesitylene. Under dynamic heating conditions, a large apparent temperature difference (ΔT) of over 100 °C was observed between the polar pNA solute and the nonpolar mesitylene solvent. This represents the first direct measurement of the selective microwave heating process. The magnitude of the selective microwave heating was affected by the properties of the agglomerated pNA. As the concentration of the pNA increases, the magnitude of the selective heating of the pNA was observed to decrease. This is explained by the tendency of the pNA dipoles to orient in an antiparallel fashion in the aggregates as measured by the Kirkwood g value, which decreased with increasing concentration. This effect reduces the net dipole moment of the agglomerates, which decreases the microwave absorption. After the radiation was terminated, the effective temperature of the dipolar molecules returned slowly to that of the medium. The slow heat transfer was modeled successfully by treating the solutions as a biphasic solvent/solute system. Based on modeling and the fact that the agglomerate can be heated above the boiling temperature of the solvent, an insulating layer of solvent vapor is suggested to form around the heated agglomerate, slowing convective heat transfer out of the agglomerate. This is an effect unique to microwave heating.
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Affiliation(s)
- Yuchuan Tao
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32312, United States
| | - Chong Teng
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32312, United States
| | - Terence D Musho
- Department of Mechanical & Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lambertus van de Burgt
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32312, United States
| | - Eric Lochner
- Department of Physics, Florida State University, Tallahassee, Florida 32312, United States
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Geoffrey F Strouse
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32312, United States
| | - Gregory B Dudley
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - A E Stiegman
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32312, United States
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16
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Heller WT. A small-angle neutron scattering study of the physical mechanism that drives the action of a viral fusion peptide. Chem Phys Lipids 2020; 234:105022. [PMID: 33253755 DOI: 10.1016/j.chemphyslip.2020.105022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 10/22/2022]
Abstract
Viruses have evolved a variety of ways for delivering their genetic cargo to a target cell. One mechanism relies on a short sequence from a protein of the virus that is referred to as a fusion peptide. In some cases, the isolated fusion peptide is also capable of causing membranes to fuse. Infection by HIV-1 involves the 23 amino acid N-terminal sequence of its gp41 envelope protein, which is capable of causing membranes to fuse by itself, but the mechanism by which it does so is not fully understood. Here, a variant of the gp41 fusion peptide that does not strongly promote fusion was studied in the presence of vesicles composed of a mixture of unsaturated lipids and cholesterol by small-angle neutron scattering and circular dichroism spectroscopy to improve the understanding of the mechanism that drives vesicle fusion. The peptide concentration and cholesterol content govern both the peptide conformation and its impact on the bilayer structure. The results indicate that the mechanism that drives vesicle fusion by the peptide is a strong distortion of the bilayer structure by the peptide when it adopts the β-sheet conformation.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States.
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17
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Li M, Heller WT, Liu CH, Gao CY, Cai Y, Hou Y, Nieh MP. Effects of fluidity and charge density on the morphology of a bicellar mixture - A SANS study. Biochim Biophys Acta Biomembr 2020; 1862:183315. [PMID: 32304755 DOI: 10.1016/j.bbamem.2020.183315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 01/28/2023]
Abstract
The spontaneously formed structures of physiologically relevant lipid model membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1,2-hexanoyl-sn-glycero-3-phosphocholine have been evaluated in depth using small angle neutron scattering. Although a common molar ratio of long- to short- chain phospholipids (~4) as reported in many bicellar mixtures was used, discoidal bicelles were not found as the major phase throughout the range of lipid concentration and temperature studied, indicating that the required condition for the formation of bicelle is the immiscibility between the long- and short- chain lipids, which were in the gel and Lα phases, respectively, in previous reports. In this study, all lipids are in the Lα phase. The characterization outcome suggests that the spontaneous structures tie strongly with the physical parameters of the system such as melting transition temperature of the long-chain lipid, total lipid concentration and charge density of the system. Multilamellar vesicles, unilamellar vesicles, ribbons and perforated lamellae can be obtained based on the analysis of the small angle neutron scattering results, leading to the construction of structural diagrams. This report provides the important map to choose suitable lipid systems for the structural study of membrane-associated proteins, design of theranostic nanocarriers or other related research fields.
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Affiliation(s)
- Ming Li
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chung-Hao Liu
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - Carrie Y Gao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yutian Cai
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Yiming Hou
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Mu-Ping Nieh
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA; Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs 06269, USA; Department of Biomedical Engineering, University of Connecticut, Storrs 06269, USA.
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18
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Jafta CJ, Bridges CA, Bai Y, Geng L, Thapaliya BP, Meyer HM, Essehli R, Heller WT, Belharouak I. Probing the Li 4 Ti 5 O 12 Interface Upon Lithium Uptake by Operando Small Angle Neutron Scattering. ChemSusChem 2020; 13:3654-3661. [PMID: 32356937 DOI: 10.1002/cssc.202000802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/28/2020] [Indexed: 06/11/2023]
Abstract
The formation of a solid-electrolyte interphase (SEI) on the surface of Li4 Ti5 O12 (LTO) has become a highly controversial topic, with arguments for it and against it. However, prior studies supporting the formation of an SEI layer have typically suggested that a layer forms upon cycling of a cell, although the layer is probed after disassembling. In this study, cubic mesostructured LTO is synthesized with crystallite domain sizes between 3 and 4 nm and uniform pores with diameters ≤8 nm. The mean pore size is controlled between 4-8 nm through the use of a triblock amphipathic copolymer with a tunable hydrophobic block as template and by thermal treatment. The LTO morphology obtained is spherical and evolves upon heat treatment. These materials show excellent electrochemical performance, including high rate capability and capacity retention. The LTO material is subjected to operando small-angle neutron scattering and X-ray photoelectron spectroscopy experiments, which reveal that the highly debated SEI forms at potentials as high as 2.2 V, first as a LiF-rich layer and subsequently by the growth of a carbonaceous layer. These SEI products form first on the smaller pores before forming on the mesopores.
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Affiliation(s)
- Charl J Jafta
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Craig A Bridges
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Yaocai Bai
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Linxiao Geng
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Bishnu P Thapaliya
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Harry M Meyer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Rachid Essehli
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Ilias Belharouak
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, 37996, USA
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19
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Archibald RK, Doucet M, Johnston T, Young SR, Yang E, Heller WT. Classifying and analyzing small-angle scattering data using weighted k nearest neighbors machine learning techniques. J Appl Crystallogr 2020. [DOI: 10.1107/s1600576720000552] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A consistent challenge for both new and expert practitioners of small-angle scattering (SAS) lies in determining how to analyze the data, given the limited information content of said data and the large number of models that can be employed. Machine learning (ML) methods are powerful tools for classifying data that have found diverse applications in many fields of science. Here, ML methods are applied to the problem of classifying SAS data for the most appropriate model to use for data analysis. The approach employed is built around the method of weighted k nearest neighbors (wKNN), and utilizes a subset of the models implemented in the SasView package (https://www.sasview.org/) for generating a well defined set of training and testing data. The prediction rate of the wKNN method implemented here using a subset of SasView models is reasonably good for many of the models, but has difficulty with others, notably those based on spherical structures. A novel expansion of the wKNN method was also developed, which uses Gaussian processes to produce local surrogate models for the classification, and this significantly improves the classification accuracy. Further, by integrating a stochastic gradient descent method during post-processing, it is possible to leverage the local surrogate model both to classify the SAS data with high accuracy and to predict the structural parameters that best describe the data. The linking of data classification and model fitting has the potential to facilitate the translation of measured data into results for both novice and expert practitioners of SAS.
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20
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Jafta CJ, Bridges CA, Sun XG, Meyer HM, Heller WT, Cunneo MJ, Paranthaman P, Dai S. Investigation of an in situ chemically formed SEI from bis(fluorosulfonyl)imide based electrolyte on ordered mesoporous carbons. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319096739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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21
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Bhattacharya S, Stanley CB, Heller WT, Friedman PA, Bu Z. Dynamic structure of the full-length scaffolding protein NHERF1 influences signaling complex assembly. J Biol Chem 2019; 294:11297-11310. [PMID: 31171716 PMCID: PMC6643037 DOI: 10.1074/jbc.ra119.008218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/05/2019] [Indexed: 01/14/2023] Open
Abstract
The Na+/H+ exchange regulatory cofactor 1 (NHERF1) protein modulates the assembly and intracellular trafficking of several transmembrane G protein-coupled receptors (GPCRs) and ion transport proteins with the membrane-cytoskeleton adapter protein ezrin. Here, we applied solution NMR and small-angle neutron scattering (SANS) to structurally characterize full-length NHERF1 and disease-associated variants that are implicated in impaired phosphate homeostasis. Using NMR, we mapped the modular architecture of NHERF1, which is composed of two structurally-independent PDZ domains that are connected by a flexible, disordered linker. We observed that the ultra-long and disordered C-terminal tail of NHERF1 has a type 1 PDZ-binding motif that interacts weakly with the proximal, second PDZ domain to form a dynamically autoinhibited structure. Using ensemble-optimized analysis of SANS data, we extracted the molecular size distribution of structures from the extensive conformational space sampled by the flexible chain. Our results revealed that NHERF1 is a diffuse ensemble of variable PDZ domain configurations and a disordered C-terminal tail. The joint NMR/SANS data analyses of three disease variants (L110V, R153Q, and E225K) revealed significant differences in the local PDZ domain structures and in the global conformations compared with the WT protein. Furthermore, we show that the substitutions affect the affinity and kinetics of NHERF1 binding to ezrin and to a C-terminal peptide from G protein-coupled receptor kinase 6A (GRK6A). These findings provide important insight into the modulation of the intrinsic flexibility of NHERF1 by disease-associated point mutations that alter the dynamic assembly of signaling complexes.
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Affiliation(s)
| | - Christopher B Stanley
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
| | - Peter A Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
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22
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Narita H, Nicolson RM, Motokawa R, Ito F, Morisaku K, Goto M, Tanaka M, Heller WT, Shiwaku H, Yaita T, Gordon RJ, Love JB, Tasker PA, Schofield ER, Antonio MR, Morrison CA. Proton Chelating Ligands Drive Improved Chemical Separations for Rhodium. Inorg Chem 2019; 58:8720-8734. [DOI: 10.1021/acs.inorgchem.9b01136] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Hirokazu Narita
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Rebecca M. Nicolson
- EaStCHEM School of Chemistry, University of Edinburgh, The King’s Buildings, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Ryuhei Motokawa
- Materials Sciences Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Fumiyuki Ito
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Kazuko Morisaku
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Midori Goto
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Mikiya Tanaka
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hideaki Shiwaku
- Materials Sciences Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Tsuyoshi Yaita
- Materials Sciences Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Ross J. Gordon
- Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, U.K
| | - Jason B. Love
- EaStCHEM School of Chemistry, University of Edinburgh, The King’s Buildings, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Peter A. Tasker
- EaStCHEM School of Chemistry, University of Edinburgh, The King’s Buildings, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Emma R. Schofield
- Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, U.K
| | - Mark R. Antonio
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Carole A. Morrison
- EaStCHEM School of Chemistry, University of Edinburgh, The King’s Buildings, David Brewster Road, Edinburgh EH9 3FJ, U.K
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23
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Motokawa R, Kobayashi T, Endo H, Mu J, Williams CD, Masters AJ, Antonio MR, Heller WT, Nagao M. A Telescoping View of Solute Architectures in a Complex Fluid System. ACS Cent Sci 2019; 5:85-96. [PMID: 30693328 PMCID: PMC6346384 DOI: 10.1021/acscentsci.8b00669] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Indexed: 05/28/2023]
Abstract
Short- and long-range correlations between solutes in solvents can influence the macroscopic chemistry and physical properties of solutions in ways that are not fully understood. The class of liquids known as complex (structured) fluids-containing multiscale aggregates resulting from weak self-assembly-are especially important in energy-relevant systems employed for a variety of chemical- and biological-based purification, separation, and catalytic processes. In these, solute (mass) transfer across liquid-liquid (water, oil) phase boundaries is the core function. Oftentimes the operational success of phase transfer chemistry is dependent upon the bulk fluid structures for which a common functional motif and an archetype aggregate is the micelle. In particular, there is an emerging consensus that mass transfer and bulk organic phase behaviors-notably the critical phenomenon of phase splitting-are impacted by the effects of micellar-like aggregates in water-in-oil microemulsions. In this study, we elucidate the microscopic structures and mesoscopic architectures of metal-, water-, and acid-loaded organic phases using a combination of X-ray and neutron experimentation as well as density functional theory and molecular dynamics simulations. The key conclusion is that the transfer of metal ions between an aqueous phase and an organic one involves the formation of small mononuclear clusters typical of metal-ligand coordination chemistry, at one extreme, in the organic phase, and their aggregation to multinuclear primary clusters that self-assemble to form even larger superclusters typical of supramolecular chemistry, at the other. Our metrical results add an orthogonal perspective to the energetics-based view of phase splitting in chemical separations known as the micellar model-founded upon the interpretation of small-angle neutron scattering data-with respect to a more general phase-space (gas-liquid) model of soft matter self-assembly and particle growth. The structure hierarchy observed in the aggregation of our quinary (zirconium nitrate-nitric acid-water-tri-n-butyl phosphate-n-octane) system is relevant to understanding solution phase transitions, in general, and the function of engineered fluids with metalloamphiphiles, in particular, for mass transfer applications, such as demixing in separation and synthesis in catalysis science.
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Affiliation(s)
- Ryuhei Motokawa
- Materials
Sciences Research Center, Japan Atomic Energy
Agency, Tokai, Ibaraki 319-1195, Japan
| | - Tohru Kobayashi
- Materials
Sciences Research Center, Japan Atomic Energy
Agency, Tokai, Ibaraki 319-1195, Japan
| | - Hitoshi Endo
- Materials
Sciences Research Center, Japan Atomic Energy
Agency, Tokai, Ibaraki 319-1195, Japan
- Neutron
Science Division, Institute of Materials Structure Science, and Materials
and Life Science Division, J-PARC Center, High Energy Accelerator Research Organization, 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
- Department
of Materials Structure Science, The Graduate
University for Advanced Studies (SOKENDAI), 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Junju Mu
- School
of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Christopher D. Williams
- School
of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Andrew J. Masters
- School
of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Mark R. Antonio
- Chemical
Sciences & Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - William T. Heller
- Neutron Scattering
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michihiro Nagao
- NIST
Center for Neutron Research, National Institute
of Standards and Technology, Gaithersburg, Maryland 20899-6102, United States
- Center
for Exploration of Energy and Matter, Department of Physics, Indiana University, Bloomington, Indiana 47408, United States
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24
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Cherpak V, Korolovych VF, Geryak R, Turiv T, Nepal D, Kelly J, Bunning TJ, Lavrentovich OD, Heller WT, Tsukruk VV. Robust Chiral Organization of Cellulose Nanocrystals in Capillary Confinement. Nano Lett 2018; 18:6770-6777. [PMID: 30351961 DOI: 10.1021/acs.nanolett.8b02522] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We showed large area uniformly aligned chiral photonic bioderived films from a liquid crystal phase formed by a cellulose nanocrystal (CNC) suspension placed in a thin capillary. As a result of the spatial confinement of the drying process, the interface between coexisting isotropic and chiral phases aligns perpendicular to the long axis of the capillary. This orientation facilitates a fast homogeneous growth of chiral pseudolayers parallel to the interface. Overall, the formation of organized solids takes hours vs weeks in contrast to the slow and heterogeneous process of drying from the traditional dish-cast approach. The saturation of water vapor in one end of the capillary causes anisotropic drying and promotes unidirectional propagation of the anisotropic phase in large regions that results in chiral CNC solid films with a uniformly oriented layered morphology. Corresponding ordering processes were monitored in situ at a nanoscale, mesoscale, and microscopic scale with complementary scattering and microscopic techniques. The resulting films show high orientation order at a multilength scale over large regions and preserved chiral handedness causing a narrower optical reflectance band and uniform birefringence over macroscopic regions in contrast to traditional dish-cast CNC films and those assembled in a magnetic field and on porous substrates. These thin films with a controllable and well-identified uniform morphology, structural colors, and handedness open up interesting possibilities for broad applications in bioderived photonic nanomaterials.
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Affiliation(s)
- V Cherpak
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - V F Korolovych
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - R Geryak
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - T Turiv
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program , Kent State University , Kent , Ohio 44240 , United States
| | - D Nepal
- Air Force Research Laboratory, Materials and Manufacturing Directorate , Wright Patterson Air Force Base , Ohio 45433 , United States
| | - J Kelly
- Air Force Research Laboratory, Materials and Manufacturing Directorate , Wright Patterson Air Force Base , Ohio 45433 , United States
| | - T J Bunning
- Air Force Research Laboratory, Materials and Manufacturing Directorate , Wright Patterson Air Force Base , Ohio 45433 , United States
| | - O D Lavrentovich
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program , Kent State University , Kent , Ohio 44240 , United States
- Department of Physics , Kent State University , Kent , Ohio 44240 , United States
| | - W T Heller
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - V V Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
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25
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Kang TH, Compton BG, Heller WT, Qian S, Smith GS, Urban VS, Duty CE, Do C. Potentials with small‐angle neutron scattering technique for understanding structure–property relation of 3D‐printed materials. POLYM ENG SCI 2018. [DOI: 10.1002/pen.24960] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tae Hui Kang
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Brett G. Compton
- Department of Mechanical, Aerospace and Biomedical Engineering University of Tennessee Knoxville Tennessee 37996
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Gregory S. Smith
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Volker S. Urban
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Chad E. Duty
- Department of Mechanical, Aerospace and Biomedical Engineering University of Tennessee Knoxville Tennessee 37996
- Manufacturing Demonstration Facility, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
| | - Changwoo Do
- Neutron Scattering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831
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26
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Callaway DJE, Matsui T, Weiss TM, Stingaciu LR, Stanley CB, Heller WT, Bu Z. Controllable activation of nanoscale dynamics in a disordered protein alters binding kinetics. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318099968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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27
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Nicholl ID, Matsui T, Weiss TM, Stanley CB, Heller WT, Callaway DJE, Bu Z. Alpha-catenin structure in solution and in complex with F-actin as revealed by small-angle X-ray and neutron scattering. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318095430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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28
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Nicholl ID, Matsui T, Weiss TM, Stanley CB, Heller WT, Martel A, Farago B, Callaway DJE, Bu Z. α-Catenin Structure and Nanoscale Dynamics in Solution and in Complex with F-Actin. Biophys J 2018; 115:642-654. [PMID: 30037495 DOI: 10.1016/j.bpj.2018.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/17/2018] [Accepted: 07/05/2018] [Indexed: 12/26/2022] Open
Abstract
As a core component of the adherens junction, α-catenin stabilizes the cadherin/catenin complexes to the actin cytoskeleton for the mechanical coupling of cell-cell adhesion. α-catenin also modulates actin dynamics, cell polarity, and cell-migration functions that are independent of the adherens junction. We have determined the solution structures of the α-catenin monomer and dimer using in-line size-exclusion chromatography small-angle X-ray scattering, as well as the structure of α-catenin dimer in complex to F-actin filament using selective deuteration and contrast-matching small angle neutron scattering. We further present the first observation, to our knowledge, of the nanoscale dynamics of α-catenin by neutron spin-echo spectroscopy, which explicitly reveals the mobile regions of α-catenin that are crucial for binding to F-actin. In solution, the α-catenin monomer is more expanded than either protomer shown in the crystal structure dimer, with the vinculin-binding M fragment and the actin-binding domain being able to adopt different configurations. The α-catenin dimer in solution is also significantly more expanded than the dimer crystal structure, with fewer interdomain and intersubunit contacts than the crystal structure. When in complex to F-actin, the α-catenin dimer has an even more open and extended conformation than in solution, with the actin-binding domain further separated from the main body of the dimer. The α-catenin-assembled F-actin bundle develops into an ordered filament packing arrangement at increasing α-catenin/F-actin molar ratios. Together, the structural and dynamic studies reveal that α-catenin possesses dynamic molecular conformations that prime this protein to function as a mechanosensor protein.
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Affiliation(s)
- Iain D Nicholl
- Department of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, United Kingdom
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | | | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | | | - David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
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Korolovych VF, Erwin A, Stryutsky A, Lee H, Heller WT, Shevchenko VV, Bulavin LA, Tsukruk VV. Thermally Responsive Hyperbranched Poly(ionic liquid)s: Assembly and Phase Transformations. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00845] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Volodymyr F. Korolovych
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Andrew Erwin
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alexandr Stryutsky
- Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kharkivske Shosse 48, Kyiv 02160, Ukraine
| | - Hansol Lee
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Valery V. Shevchenko
- Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kharkivske Shosse 48, Kyiv 02160, Ukraine
| | - Leonid A. Bulavin
- Taras Shevchenko
National University of Kyiv, Volodymyrska Str. 64, 01601 Kyiv, Ukraine
| | - Vladimir V. Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Heller WT, Cuneo M, Debeer-Schmitt L, Do C, He L, Heroux L, Littrell K, Pingali SV, Qian S, Stanley C, Urban VS, Wu B, Bras W. The suite of small-angle neutron scattering instruments at Oak Ridge National Laboratory. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718001231] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Oak Ridge National Laboratory is home to the High Flux Isotope Reactor (HFIR), a high-flux research reactor, and the Spallation Neutron Source (SNS), the world's most intense source of pulsed neutron beams. The unique co-localization of these two sources provided an opportunity to develop a suite of complementary small-angle neutron scattering instruments for studies of large-scale structures: the GP-SANS and Bio-SANS instruments at the HFIR and the EQ-SANS and TOF-USANS instruments at the SNS. This article provides an overview of the capabilities of the suite of instruments, with specific emphasis on how they complement each other. A description of the plans for future developments including greater integration of the suite into a single point of entry for neutron scattering studies of large-scale structures is also provided.
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Kang T, Qian S, Smith GS, Do C, Heller WT. Small-angle neutron scattering study of a dense microemulsion system formed with an ionic liquid. Soft Matter 2017; 13:7154-7160. [PMID: 28895963 DOI: 10.1039/c7sm01516j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mixtures of water, octane and 1-octanol with 1-tetradecyl-3-methylimidazolium chloride (C14MIM·Cl), often referred to as a surface active ionic liquid (SAIL), form water-in-oil microemulsions that have potential application as extraction media for various metal ions. Here, we present a structural study by small-angle neutron scattering (SANS) of dense microemulsions formed by surfactant-rich mixtures of these four compounds to understand how the SAIL can be used to tune the structures and properties of the microemulsions. The SANS experiments revealed that the microemulsions formed are composed of two phases, a water-in-oil microemulsion and a bicontinuous microemulsion, which becomes the dominant phase at high surfactant concentration. In this concentration regime, the surfactant film becomes more rigid, having a higher bending modulus that results from the parallel stacking of the imidazolium ring of the SAIL. At lower surfactant concentrations, the molecular packing of the SAIL does not change with the water content of the microemulsion. The results presented here correlate well with previously observed changes in the interaction between the IL cation and metal ions (Y. Tong, L. Han and Y. Yang, Ind. Eng. Chem. Res., 2012, 51, 16438-16443), while the capacity of the microemulsion system for water remains high enough for using the system as an extraction medium.
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Affiliation(s)
- T Kang
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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32
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Brown P, Sresht V, Eral BH, Fiore A, de la Fuente-Núñez C, O'Mahony M, Mendes GP, Heller WT, Doyle PS, Blankschtein D, Hatton TA. Correction to "CO 2-Reactive Ionic Liquid Surfactants for the Control of Colloidal Morphology". Langmuir 2017; 33:9244. [PMID: 28836795 DOI: 10.1021/acs.langmuir.7b02866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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Jang Y, Choi WT, Heller WT, Ke Z, Wright ER, Champion JA. Engineering Globular Protein Vesicles through Tunable Self-Assembly of Recombinant Fusion Proteins. Small 2017; 13. [PMID: 28748658 DOI: 10.1002/smll.201700399] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 06/01/2017] [Indexed: 05/16/2023]
Abstract
Vesicles assembled from folded, globular proteins have potential for functions different from traditional lipid or polymeric vesicles. However, they also present challenges in understanding the assembly process and controlling vesicle properties. From detailed investigation of the assembly behavior of recombinant fusion proteins, this work reports a simple strategy to engineer protein vesicles containing functional, globular domains. This is achieved through tunable self-assembly of recombinant globular fusion proteins containing leucine zippers and elastin-like polypeptides. The fusion proteins form complexes in solution via high affinity binding of the zippers, and transition through dynamic coacervates to stable hollow vesicles upon warming. The thermal driving force, which can be tuned by protein concentration or temperature, controls both vesicle size and whether vesicles are single or bi-layered. These results provide critical information to engineer globular protein vesicles via self-assembly with desired size and membrane structure.
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Affiliation(s)
- Yeongseon Jang
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
| | - Won Tae Choi
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6473, Oak Ridge, TN, 37831, USA
| | - Zunlong Ke
- Division of Infectious Diseases, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
- School of Biology, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
| | - Elizabeth R Wright
- Division of Infectious Diseases, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Julie A Champion
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, GA, 30332, USA
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34
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Brown P, Sresht V, Eral BH, Fiore A, de la Fuente-Núñez C, O'Mahony M, Mendes GP, Heller WT, Doyle PS, Blankschtein D, Hatton TA. CO 2-Reactive Ionic Liquid Surfactants for the Control of Colloidal Morphology. Langmuir 2017; 33:7633-7641. [PMID: 28699755 DOI: 10.1021/acs.langmuir.7b00679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This article reports on a new class of stimuli-responsive surfactant generated from commercially available amphiphiles such as dodecyltrimethylammmonium bromide (DTAB) by substitution of the halide counterion with counterions such as 2-cyanopyrrolide, 1,2,3-triazolide, and L-proline that complex reversibly with CO2. Through a combination of small-angle neutron scattering (SANS), electrical conductivity measurements, thermal gravimetric analysis, and molecular dynamics simulations, we show how small changes in charge reorganization and counterion shape and size induced by complexation with CO2 allow for fine-tunability of surfactant properties. We then use these findings to demonstrate a range of potential practical uses, from manipulating microemulsion droplet morphology to controlling micellar and vesicular aggregation. In particular, we focus on the binding of these surfactants to DNA and the reversible compaction of surfactant-DNA complexes upon alternate bubbling of the solution with CO2 and N2.
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Affiliation(s)
| | | | | | | | - César de la Fuente-Núñez
- Eli and Edythe L. Broad Institute of MIT and Harvard , 415 Main Street, Cambridge, Massachusetts 02142, United States
- Harvard Biophysics Program, Harvard University , Cambridge, Massachusetts 02138, United States
| | | | | | - William T Heller
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Callaway DJE, Matsui T, Weiss T, Stingaciu LR, Stanley CB, Heller WT, Bu Z. Controllable Activation of Nanoscale Dynamics in a Disordered Protein Alters Binding Kinetics. J Mol Biol 2017; 429:987-998. [PMID: 28285124 DOI: 10.1016/j.jmb.2017.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/04/2017] [Accepted: 03/02/2017] [Indexed: 01/03/2023]
Abstract
The phosphorylation of specific residues in a flexible disordered activation loop yields precise control of signal transduction. One paradigm is the phosphorylation of S339/S340 in the intrinsically disordered tail of the multi-domain scaffolding protein NHERF1, which affects the intracellular localization and trafficking of NHERF1 assembled signaling complexes. Using neutron spin echo spectroscopy (NSE), we show salt-concentration-dependent excitation of nanoscale motion at the tip of the C-terminal tail in the phosphomimic S339D/S340D mutant. The "tip of the whip" that is unleashed is near the S339/S340 phosphorylation site and flanks the hydrophobic Ezrin-binding motif. The kinetic association rate constant of the binding of the S339D/S340D mutant to the FERM domain of Ezrin is sensitive to buffer salt concentration, correlating with the excited nanoscale dynamics. The results suggest that electrostatics modulates the activation of nanoscale dynamics of an intrinsically disordered protein, controlling the binding kinetics of signaling partners. NSE can pinpoint the nanoscale dynamics changes in a highly specific manner.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Thomas Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Laura R Stingaciu
- Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher B Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
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36
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Srivastava S, Andreev M, Levi AE, Goldfeld DJ, Mao J, Heller WT, Prabhu VM, de Pablo JJ, Tirrell MV. Gel phase formation in dilute triblock copolyelectrolyte complexes. Nat Commun 2017; 8:14131. [PMID: 28230046 PMCID: PMC5331217 DOI: 10.1038/ncomms14131] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/01/2016] [Indexed: 01/03/2023] Open
Abstract
Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (<1% by mass) has been observed in scattering experiments and molecular dynamics simulations. Here we show that in contrast to uncharged, amphiphilic block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.
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Affiliation(s)
- Samanvaya Srivastava
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Marat Andreev
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
| | - Adam E. Levi
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
| | - David J. Goldfeld
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
| | - Jun Mao
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - William T. Heller
- Biology & Soft Matter Division, Oak Ridge National laboratory, Oak Ridge, Tennessee 37831, USA
| | - Vivek M. Prabhu
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Juan J. de Pablo
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Matthew V. Tirrell
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, USA
- Institute for Molecular Engineering, Argonne National Laboratory, Lemont, Illinois 60439, USA
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37
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Etampawala TN, Aryal D, Osti NC, He L, Heller WT, Willis CL, Grest GS, Perahia D. Association of a multifunctional ionic block copolymer in a selective solvent. J Chem Phys 2016; 145:184903. [DOI: 10.1063/1.4967291] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Dipak Aryal
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
| | - Naresh C. Osti
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
| | - Lilin He
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - William T. Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Carl L. Willis
- Kraton Polymers US LLC, 16400 Park Row, Houston, Texas 77084, USA
| | - Gary S. Grest
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Dvora Perahia
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
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Rai DK, Sharma VK, Anunciado D, O'Neill H, Mamontov E, Urban V, Heller WT, Qian S. Neutron Scattering Studies of the Interplay of Amyloid β Peptide(1-40) and An Anionic Lipid 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol. Sci Rep 2016; 6:30983. [PMID: 27503057 PMCID: PMC4995599 DOI: 10.1038/srep30983] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 07/05/2016] [Indexed: 12/19/2022] Open
Abstract
The interaction between lipid bilayers and Amyloid β peptide (Aβ) plays a critical role in proliferation of Alzheimer’s disease (AD). AD is expected to affect one in every 85 humans by 2050, and therefore, deciphering the interplay of Aβ and lipid bilayers at the molecular level is of profound importance. In this work, we applied an array of neutron scattering methods to study the structure and dynamics of Aβ(1–40) interacting 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) bilayers. In the structural investigations of lipid bilayer’s response to Aβ binding, Small Angle Neutron Scattering and Neutron Membrane Diffraction revealed that the Aβ anchors firmly to the highly charged DMPG bilayers in the interfacial region between water and hydrocarbon chain, and it doesn’t penetrate deeply into the bilayer. This association mode is substantiated by the dynamics studies with high resolution Quasi-Elastic Neutron Scattering experiments, showing that the addition of Aβ mainly affects the slower lateral motion of lipid molecules, especially in the fluid phase, but not the faster internal motion. The results revealed that Aβ associates with the highly charged membrane in surface with limited impact on the structure, but the altered membrane dynamics could have more influence on other membrane processes.
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Affiliation(s)
- Durgesh K Rai
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Veerendra K Sharma
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Divina Anunciado
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Hugh O'Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Volker Urban
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Motokawa R, Endo H, Nagao M, Heller WT. Neutron Polarization Analysis for Biphasic Solvent Extraction Systems. Solvent Extraction and Ion Exchange 2016. [DOI: 10.1080/07366299.2016.1201980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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40
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Osti NC, Naguib M, Ostadhossein A, Xie Y, Kent PRC, Dyatkin B, Rother G, Heller WT, van Duin ACT, Gogotsi Y, Mamontov E. Effect of Metal Ion Intercalation on the Structure of MXene and Water Dynamics on its Internal Surfaces. ACS Appl Mater Interfaces 2016; 8:8859-8863. [PMID: 27010763 DOI: 10.1021/acsami.6b01490] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
MXenes are a recently discovered class of 2D materials with an excellent potential for energy storage applications. Because MXene surfaces are hydrophilic and attractive interaction forces between the layers are relatively weak, water molecules can spontaneously intercalate at ambient humidity and significantly influence the key properties of this 2D material. Using complementary X-ray and neutron scattering techniques, we demonstrate that intercalation with potassium cations significantly improves structural homogeneity and water stability in MXenes. In agreement with molecular dynamics simulations, intercalated potassium ions reduce the water self-diffusion coefficient by 2 orders of magnitude, suggesting greater stability of hydrated MXene against changing environmental conditions.
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Affiliation(s)
- Naresh C Osti
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Michael Naguib
- Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Alireza Ostadhossein
- Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16801, United States
| | - Yu Xie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Paul R C Kent
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Computer Science and Mathematics Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Boris Dyatkin
- Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Gernot Rother
- Chemical Science Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Adri C T van Duin
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University , University Park, Pennsylvania 16801, United States
| | - Yury Gogotsi
- Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States
| | - Eugene Mamontov
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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41
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Vandavasi VG, Putnam DK, Zhang Q, Petridis L, Heller WT, Nixon BT, Haigler CH, Kalluri U, Coates L, Langan P, Smith JC, Meiler J, O'Neill H. Structural Studies of Plant CESA Support Eighteen CESAs in the Plant CSC. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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42
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Vandavasi VG, Putnam DK, Zhang Q, Petridis L, Heller WT, Nixon BT, Haigler CH, Kalluri U, Coates L, Langan P, Smith JC, Meiler J, O'Neill H. A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers. Plant Physiol 2016; 170:123-35. [PMID: 26556795 PMCID: PMC4704586 DOI: 10.1104/pp.15.01356] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/05/2015] [Indexed: 05/18/2023]
Abstract
A cellulose synthesis complex with a "rosette" shape is responsible for synthesis of cellulose chains and their assembly into microfibrils within the cell walls of land plants and their charophyte algal progenitors. The number of cellulose synthase proteins in this large multisubunit transmembrane protein complex and the number of cellulose chains in a microfibril have been debated for many years. This work reports a low resolution structure of the catalytic domain of CESA1 from Arabidopsis (Arabidopsis thaliana; AtCESA1CatD) determined by small-angle scattering techniques and provides the first experimental evidence for the self-assembly of CESA into a stable trimer in solution. The catalytic domain was overexpressed in Escherichia coli, and using a two-step procedure, it was possible to isolate monomeric and trimeric forms of AtCESA1CatD. The conformation of monomeric and trimeric AtCESA1CatD proteins were studied using small-angle neutron scattering and small-angle x-ray scattering. A series of AtCESA1CatD trimer computational models were compared with the small-angle x-ray scattering trimer profile to explore the possible arrangement of the monomers in the trimers. Several candidate trimers were identified with monomers oriented such that the newly synthesized cellulose chains project toward the cell membrane. In these models, the class-specific region is found at the periphery of the complex, and the plant-conserved region forms the base of the trimer. This study strongly supports the "hexamer of trimers" model for the rosette cellulose synthesis complex that synthesizes an 18-chain cellulose microfibril as its fundamental product.
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Affiliation(s)
- Venu Gopal Vandavasi
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Daniel K Putnam
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Qiu Zhang
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Loukas Petridis
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - William T Heller
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - B Tracy Nixon
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Candace H Haigler
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Udaya Kalluri
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Leighton Coates
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Paul Langan
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Jeremy C Smith
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Jens Meiler
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
| | - Hugh O'Neill
- Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.)
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43
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Das A, Gerlits O, Parks JM, Langan P, Kovalevsky A, Heller WT. Protein Kinase A Catalytic Subunit Primed for Action: Time-Lapse Crystallography of Michaelis Complex Formation. Structure 2015; 23:2331-2340. [PMID: 26585512 DOI: 10.1016/j.str.2015.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/31/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
Abstract
The catalytic subunit of the cyclic AMP-dependent protein kinase A (PKAc) catalyzes the transfer of the γ-phosphate of bound Mg2ATP to a serine or threonine residue of a protein substrate. Here, time-lapse X-ray crystallography was used to capture a series of complexes of PKAc with an oligopeptide substrate and unreacted Mg2ATP, including the Michaelis complex, that reveal important geometric rearrangements in and near the active site preceding the phosphoryl transfer reaction. Contrary to the prevailing view, Mg(2+) binds first to the M1 site as a complex with ATP and is followed by Mg(2+) binding to the M2 site. Concurrently, the target serine hydroxyl of the peptide substrate rotates away from the active site toward the bulk solvent, which breaks the hydrogen bond with D166. Lastly, the serine hydroxyl of the substrate rotates back toward D166 to form the Michaelis complex with the active site primed for phosphoryl transfer.
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Affiliation(s)
- Amit Das
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Oksana Gerlits
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jerry M Parks
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Paul Langan
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Andrey Kovalevsky
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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44
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Motokawa R, Kobayashi T, Endo H, Ikeda T, Yaita T, Suzuki S, Narita H, Akutsu K, Heller WT. Small-angle neutron scattering study of specific interaction and coordination structure formed by mono-acetyl-substituted dibenzo-20-crown-6-ether and cesium ions. J NUCL SCI TECHNOL 2015. [DOI: 10.1080/00223131.2015.1102100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ryuhei Motokawa
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Tohru Kobayashi
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Hitoshi Endo
- Neutron Science Division, Institute of Material Science, High Energy Accelerator Research Organization, 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
- Department of Material Structure Science, The Graduate University for Advanced Studies (SOKENDAI), 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Takashi Ikeda
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Tsuyoshi Yaita
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Shinichi Suzuki
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - Hirokazu Narita
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Kazuhiro Akutsu
- Quantum Beam Science Center (QuBS), Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
| | - William T. Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA
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45
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Qian S, Heller WT. Melittin-induced cholesterol reorganization in lipid bilayer membranes. Biochimica et Biophysica Acta (BBA) - Biomembranes 2015; 1848:2253-60. [DOI: 10.1016/j.bbamem.2015.06.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 06/05/2015] [Accepted: 06/10/2015] [Indexed: 11/27/2022]
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46
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Gerlits O, Tian J, Das A, Langan P, Heller WT, Kovalevsky A. Phosphoryl Transfer Reaction Snapshots in Crystals: INSIGHTS INTO THE MECHANISM OF PROTEIN KINASE A CATALYTIC SUBUNIT. J Biol Chem 2015; 290:15538-15548. [PMID: 25925954 DOI: 10.1074/jbc.m115.643213] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Indexed: 11/06/2022] Open
Abstract
To study the catalytic mechanism of phosphorylation catalyzed by cAMP-dependent protein kinase (PKA) a structure of the enzyme-substrate complex representing the Michaelis complex is of specific interest as it can shed light on the structure of the transition state. However, all previous crystal structures of the Michaelis complex mimics of the PKA catalytic subunit (PKAc) were obtained with either peptide inhibitors or ATP analogs. Here we utilized Ca(2+) ions and sulfur in place of the nucleophilic oxygen in a 20-residue pseudo-substrate peptide (CP20) and ATP to produce a close mimic of the Michaelis complex. In the ternary reactant complex, the thiol group of Cys-21 of the peptide is facing Asp-166 and the sulfur atom is positioned for an in-line phosphoryl transfer. Replacement of Ca(2+) cations with Mg(2+) ions resulted in a complex with trapped products of ATP hydrolysis: phosphate ion and ADP. The present structural results in combination with the previously reported structures of the transition state mimic and phosphorylated product complexes complete the snapshots of the phosphoryl transfer reaction by PKAc, providing us with the most thorough picture of the catalytic mechanism to date.
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Affiliation(s)
- Oksana Gerlits
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Jianhui Tian
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Amit Das
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Paul Langan
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - William T Heller
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831.
| | - Andrey Kovalevsky
- From the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831.
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47
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Chen X, Khajeh JA, Ju JH, Gupta YK, Stanley CB, Do C, Heller WT, Aggarwal AK, Callaway DJE, Bu Z. Phosphatidylinositol 4,5-bisphosphate clusters the cell adhesion molecule CD44 and assembles a specific CD44-Ezrin heterocomplex, as revealed by small angle neutron scattering. J Biol Chem 2015; 290:6639-52. [PMID: 25572402 PMCID: PMC4358296 DOI: 10.1074/jbc.m114.589523] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/30/2014] [Indexed: 01/02/2023] Open
Abstract
The cell adhesion molecule CD44 regulates diverse cellular functions, including cell-cell and cell-matrix interaction, cell motility, migration, differentiation, and growth. In cells, CD44 co-localizes with the membrane-cytoskeleton adapter protein Ezrin that links the CD44 assembled receptor signaling complexes to the cytoskeletal actin network, which organizes the spatial and temporal localization of signaling events. Here we report that the cytoplasmic tail of CD44 (CD44ct) is largely disordered. Upon binding to the signaling lipid phosphatidylinositol 4,5-bisphosphate (PIP2), CD44ct clusters into aggregates. Further, contrary to the generally accepted model, CD44ct does not bind directly to the FERM domain of Ezrin or to the full-length Ezrin but only forms a complex with FERM or with the full-length Ezrin in the presence of PIP2. Using contrast variation small angle neutron scattering, we show that PIP2 mediates the assembly of a specific heterotetramer complex of CD44ct with Ezrin. This study reveals the role of PIP2 in clustering CD44 and in assembling multimeric CD44-Ezrin complexes. We hypothesize that polyvalent electrostatic interactions are responsible for the assembly of CD44 clusters and the multimeric PIP2-CD44-Ezrin complexes.
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Affiliation(s)
- Xiaodong Chen
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031, the School of Pharmacy, Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi 330004, China
| | - Jahan Ali Khajeh
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Jeong Ho Ju
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Yogesh K Gupta
- the Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, and
| | - Christopher B Stanley
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Changwoo Do
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - William T Heller
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Aneel K Aggarwal
- the Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, and
| | - David J E Callaway
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031
| | - Zimei Bu
- From the Department of Chemistry and Biochemistry, City College of New York, New York, New York 10031,
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48
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Kumar R, Lokitz BS, Sides SW, Chen J, Heller WT, Ankner JF, Browning JF, Kilbey II SM, Sumpter BG. Microphase separation in thin films of lamellar forming polydisperse di-block copolymers. RSC Adv 2015. [DOI: 10.1039/c5ra00974j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Effects of polydispersity in chain lengths on microphase separation in thin films of di-block copolymers are studied using self-consistent field theory (SCFT) and neutron reflectivity experiments.
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Affiliation(s)
- Rajeev Kumar
- Computer Science and Mathematics Division
- Oak Ridge National Lab
- Oak Ridge
- USA
- Center for Nanophase Materials Sciences
| | - Bradley S. Lokitz
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | - Jihua Chen
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | - John F. Ankner
- Spallation Neutron Source
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | | | - Bobby G. Sumpter
- Computer Science and Mathematics Division
- Oak Ridge National Lab
- Oak Ridge
- USA
- Center for Nanophase Materials Sciences
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49
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Qian S, Rai D, Heller WT. Alamethicin Disrupts the Cholesterol Distribution in Dimyristoyl Phosphatidylcholine–Cholesterol Lipid Bilayers. J Phys Chem B 2014; 118:11200-8. [DOI: 10.1021/jp504886u] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shuo Qian
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
| | - Durgesh Rai
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
| | - William T. Heller
- Center for Structural Molecular Biology and ‡Biology and Soft Matter Division; Oak Ridge National Laboratory; P.O. Box 2008, MS-6473; Oak Ridge, Tennessee 37831, United States
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50
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Blumenthal DK, Copps J, Smith-Nguyen EV, Zhang P, Heller WT, Taylor SS. The roles of the RIIβ linker and N-terminal cyclic nucleotide-binding domain in determining the unique structures of the type IIβ protein kinase A: a small angle x-ray and neutron scattering study. J Biol Chem 2014; 289:28505-12. [PMID: 25112875 DOI: 10.1074/jbc.m114.584177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase A (PKA) is ubiquitously expressed and is responsible for regulating many important cellular functions in response to changes in intracellular cAMP concentrations. The PKA holoenzyme is a tetramer (R2:C2), with a regulatory subunit homodimer (R2) that binds and inhibits two catalytic (C) subunits; binding of cAMP to the regulatory subunit homodimer causes activation of the catalytic subunits. Four different R subunit isoforms exist in mammalian cells, and these confer different structural features, subcellular localization, and biochemical properties upon the PKA holoenzymes they form. The holoenzyme containing RIIβ is structurally unique in that the type IIβ holoenzyme is much more compact than the free RIIβ homodimer. We have used small angle x-ray scattering and small angle neutron scattering to study the solution structure and subunit organization of a holoenzyme containing an RIIβ C-terminal deletion mutant (RIIβ(1-280)), which is missing the C-terminal cAMP-binding domain to better understand the structural organization of the type IIβ holoenzyme and the RIIβ domains that contribute to stabilizing the holoenzyme conformation. Our results demonstrate that compaction of the type IIβ holoenzyme does not require the C-terminal cAMP-binding domain but rather involves large structural rearrangements within the linker and N-terminal cyclic nucleotide-binding domain of the RIIβ homodimer. The structural rearrangements are significantly greater than seen previously with RIIα and are likely to be important in mediating short range and long range interdomain and intersubunit interactions that uniquely regulate the activity of the type IIβ isoform of PKA.
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Affiliation(s)
- Donald K Blumenthal
- From the Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112,
| | - Jeffrey Copps
- the Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0654
| | - Eric V Smith-Nguyen
- the Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0654
| | - Ping Zhang
- the Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0654
| | - William T Heller
- the Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and
| | - Susan S Taylor
- the Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0654, the Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0654
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