1
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Biswal S, Agmon N. Collagen Structured Hydration. Biomolecules 2023; 13:1744. [PMID: 38136615 PMCID: PMC10742079 DOI: 10.3390/biom13121744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023] Open
Abstract
Collagen is a triple-helical protein unique to the extracellular matrix, conferring rigidity and stability to tissues such as bone and tendon. For the [(PPG)10]3 collagen-mimetic peptide at room temperature, our molecular dynamics simulations show that these properties result in a remarkably ordered first hydration layer of water molecules hydrogen bonded to the backbone carbonyl (bb-CO) oxygen atoms. This originates from the following observations. The radius of gyration attests that the PPG triplets are organized along a straight line, so that all triplets (excepting the ends) are equivalent. The solvent-accessible surface area (SASA) for the bb-CO oxygens shows a repetitive regularity for every triplet. This leads to water occupancy of the bb-CO sites following a similar regularity. In the crystal-phase X-ray data, as well as in our 100 K simulations, we observe a 0-2-1 water occupancy in the P-P-G triplet. Surprisingly, a similar (0-1.7-1) regularity is maintained in the liquid phase, in spite of the sub-nsec water exchange rates, because the bb-CO sites rarely remain vacant. The manifested ordered first-shell water molecules are expected to produce a cylindrical electrostatic potential around the peptide, to be investigated in future work.
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Affiliation(s)
| | - Noam Agmon
- The Fritz Haber Research Center, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel;
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2
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Wieske LHE, Atilaw Y, Poongavanam V, Erdélyi M, Kihlberg J. Going Viral: An Investigation into the Chameleonic Behaviour of Antiviral Compounds. Chemistry 2023; 29:e202202798. [PMID: 36286339 PMCID: PMC10107787 DOI: 10.1002/chem.202202798] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/23/2022] [Accepted: 10/25/2022] [Indexed: 12/15/2022]
Abstract
The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6 ) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as "partial molecular chameleons" and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.
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Affiliation(s)
- Lianne H E Wieske
- Department of Chemistry - BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
| | - Yoseph Atilaw
- Department of Chemistry - BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
| | | | - Máté Erdélyi
- Department of Chemistry - BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
| | - Jan Kihlberg
- Department of Chemistry - BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
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3
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Poongavanam V, Atilaw Y, Siegel S, Giese A, Lehmann L, Meibom D, Erdelyi M, Kihlberg J. Linker-Dependent Folding Rationalizes PROTAC Cell Permeability. J Med Chem 2022; 65:13029-13040. [PMID: 36170570 PMCID: PMC9574858 DOI: 10.1021/acs.jmedchem.2c00877] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proteolysis-targeting chimeras (PROTACs) must be cell permeable to reach their target proteins. This is challenging as the bivalent structure of PROTACs puts them in chemical space at, or beyond, the outer limits of oral druggable space. We used NMR spectroscopy and molecular dynamics (MD) simulations independently to gain insights into the origin of the differences in cell permeability displayed by three flexible cereblon PROTACs having closely related structures. Both methods revealed that the propensity of the PROTACs to adopt folded conformations with a low solvent-accessible 3D polar surface area in an apolar environment is correlated to high cell permeability. The chemical nature and the flexibility of the linker were essential for the PROTACs to populate folded conformations stabilized by intramolecular hydrogen bonds, π-π interactions, and van der Waals interactions. We conclude that MD simulations may be used for the prospective ranking of cell permeability in the design of cereblon PROTACs.
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Affiliation(s)
| | - Yoseph Atilaw
- Department of Chemistry─BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | - Stephan Siegel
- Drug Discovery Sciences, Bayer AG, 13342 Berlin, Germany
| | - Anja Giese
- Drug Discovery Sciences, Bayer AG, 13342 Berlin, Germany
| | - Lutz Lehmann
- Drug Discovery Sciences, Bayer AG, 42113 Wuppertal, Germany
| | - Daniel Meibom
- Drug Discovery Sciences, Bayer AG, 42113 Wuppertal, Germany
| | - Mate Erdelyi
- Department of Chemistry─BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | - Jan Kihlberg
- Department of Chemistry─BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
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4
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Olawale F, Ogunyemi O, Folorunso IM. Repurposing clinically approved drugs as Wee1 checkpoint kinase inhibitors: an in silico investigation integrating molecular docking, ensemble QSAR modelling and molecular dynamics simulation. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2101673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Femi Olawale
- Nano-Gene and Drug Delivery Group, Department of Biochemistry, School of life science, University of KwaZulu Natal, Durban, South Africa
| | - Oludare Ogunyemi
- Human Nutraceuticals and Bioinformatics Research Unit, Department of Biochemistry, Salem University, Lokoja, Nigeria
| | - Ibukun Mary Folorunso
- Bioinformatics and Molecular Biology Unit, Department of Biochemistry, Federal University of Technology Akure, Akure, Nigeria
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5
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Begnini F, Poongavanam V, Atilaw Y, Erdelyi M, Schiesser S, Kihlberg J. Cell Permeability of Isomeric Macrocycles: Predictions and NMR Studies. ACS Med Chem Lett 2021; 12:983-990. [PMID: 34136079 PMCID: PMC8201747 DOI: 10.1021/acsmedchemlett.1c00126] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
![]()
Conformation-dependent 3D descriptors
have been shown to provide
better predictions of the physicochemical properties of macrocycles
than 2D descriptors. However, the computational identification of
relevant conformations for macrocycles is nontrivial. Herein, we report
that the Caco-2 cell permeability difference between a pair of diastereomeric
macrocycles correlated with their solvent accessible 3D polar surface
area and radius of gyration. The descriptors were calculated from
the macrocycles’ solution-phase conformational ensembles and
independently from ensembles obtained by conformational sampling.
Calculation of the two descriptors for three other stereo- and regioisomeric
macrocycles also allowed the correct ranking of their cell permeability.
Methods for conformational sampling may thus allow ranking of passive
permeability for moderately flexible macrocycles, thereby contributing
to the prioritization of macrocycles for synthesis in lead optimization.
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Affiliation(s)
- Fabio Begnini
- Department of Chemistry - BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | | | - Yoseph Atilaw
- Department of Chemistry - BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | - Mate Erdelyi
- Department of Chemistry - BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | - Stefan Schiesser
- Department of Medicinal Chemistry, Research and Early Development, Respiratory and Immunology (R&I), BioPharmaceuticals R&D, AstraZeneca, Pepparedsleden 1, 43183 Mölndal, Sweden
| | - Jan Kihlberg
- Department of Chemistry - BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
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6
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Atilaw Y, Poongavanam V, Svensson Nilsson C, Nguyen D, Giese A, Meibom D, Erdelyi M, Kihlberg J. Solution Conformations Shed Light on PROTAC Cell Permeability. ACS Med Chem Lett 2021; 12:107-114. [PMID: 33488971 PMCID: PMC7812666 DOI: 10.1021/acsmedchemlett.0c00556] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/18/2020] [Indexed: 12/18/2022] Open
Abstract
![]()
Proteolysis
targeting chimeras (PROTACs) induce intracellular degradation
of target proteins. Their bifunctional structure puts degraders in
a chemical space where ADME properties often complicate drug discovery.
Herein we provide the first structural insight into PROTAC cell permeability
obtained by NMR studies of a VHL-based PROTAC (1), which
is cell permeable despite having a high molecular weight and polarity
and a large number of rotatable bonds. We found that 1 populates elongated and polar conformations in solutions that mimic
extra- and intracellular compartments. Conformations were folded and
had a smaller polar surface area in chloroform, mimicking a cell membrane
interior. Formation of intramolecular and nonclassical hydrogen bonds,
π–π interactions, and shielding of amide groups
from solvent all facilitate cell permeability by minimization of size
and polarity. We conclude that molecular chameleonicity appears to
be of major importance for 1 to enter into target cells.
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Affiliation(s)
- Yoseph Atilaw
- Department of Chemistry - BMC, Uppsala University, SE-75123 Uppsala, Sweden
| | | | | | - Duy Nguyen
- Nuvisan Innovation Campus Berlin GmbH, Muellerstrasse 178, 13353 Berlin, Germany
| | - Anja Giese
- Drug Discovery Sciences, Bayer AG, 13342 Berlin, Germany
| | - Daniel Meibom
- Drug Discovery Sciences, Bayer AG, 42113 Wuppertal, Germany
| | - Mate Erdelyi
- Department of Chemistry - BMC, Uppsala University, SE-75123 Uppsala, Sweden
| | - Jan Kihlberg
- Department of Chemistry - BMC, Uppsala University, SE-75123 Uppsala, Sweden
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7
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Pechmann S. Programmed Trade-offs in Protein Folding Networks. Structure 2020; 28:1361-1375.e4. [PMID: 33053320 DOI: 10.1016/j.str.2020.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/25/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022]
Abstract
Molecular chaperones as specialized protein quality control enzymes form the core of cellular protein homeostasis. How chaperones selectively interact with their substrate proteins thus allocate their overall limited capacity remains poorly understood. Here, I present an integrated analysis of sequence and structural determinants that define interactions of protein domains as the basic protein folding unit with the Saccharomyces cerevisiae Hsp70 Ssb. Structural homologs of single-domain proteins that differentially interact with Ssb for de novo folding were found to systematically differ in complexity of their folding landscapes, selective use of nonoptimal codons, and presence of short discriminative sequences, thus highlighting pervasive trade-offs in chaperone-assisted protein folding landscapes. However, short discriminative sequences were found to contribute by far the strongest signal toward explaining Ssb interactions. This observation suggested that some chaperone interactions may be directly programmed in the amino acid sequences rather than responding to folding challenges, possibly for regulatory advantages.
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Affiliation(s)
- Sebastian Pechmann
- Département de biochimie, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada.
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8
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Bhat R, Kaushik R, Singh A, DasGupta D, Jayaraj A, Soni A, Shandilya A, Shekhar V, Shekhar S, Jayaram B. A comprehensive automated computer-aided discovery pipeline from genomes to hit molecules. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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9
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Danelius E, Poongavanam V, Peintner S, Wieske LHE, Erdélyi M, Kihlberg J. Solution Conformations Explain the Chameleonic Behaviour of Macrocyclic Drugs. Chemistry 2020; 26:5231-5244. [DOI: 10.1002/chem.201905599] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Indexed: 02/02/2023]
Affiliation(s)
- Emma Danelius
- Department of Chemistry-BMCUppsala University 75123 Uppsala Sweden
| | | | - Stefan Peintner
- Department of Chemistry-BMCUppsala University 75123 Uppsala Sweden
| | | | - Máté Erdélyi
- Department of Chemistry-BMCUppsala University 75123 Uppsala Sweden
| | - Jan Kihlberg
- Department of Chemistry-BMCUppsala University 75123 Uppsala Sweden
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10
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Panteli JT, Van Dessel N, Forbes NS. Detection of tumors with fluoromarker-releasing bacteria. Int J Cancer 2020; 146:137-149. [PMID: 31093970 PMCID: PMC10411319 DOI: 10.1002/ijc.32414] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 03/14/2019] [Accepted: 03/25/2019] [Indexed: 01/21/2023]
Abstract
Combining the specificity of tumor-targeting bacteria with the sensitivity of biomarker detection would create a screening method able to detect small tumors and metastases. To create this system, we genetically modified an attenuated strain of Salmonella enterica to release a recombinant fluorescent biomarker (or fluoromarker). Salmonella expressing ZsGreen were intravenously administered to tumor-bearing mice and fluoromarker production was induced after 48 hr. The quantities and locations of bacteria and ZsGreen were measured in tumors, livers and spleens by immunofluorescence, and the plasma concentration of ZsGreen was measured using single-layer ELISA. In the plasma, the ZsGreen concentration was in the range of 0.5-1.5 ng/ml and was dependent on tumor mass (with a proportion of 0.81 ± 0.32 ng·ml-1 ·g-1 ). No adverse reaction to ZsGreen or bacteria was observed in any mice. ZsGreen was released at an average rate of 4.3 fg·CFU-1 ·hr-1 and cleared from the plasma with a rate constant of 0.259 hr-1 . ZsGreen production was highest in viable tissue (7.6 fg·CFU-1 ·hr-1 ) and lowest in necrotic tissue (0.47 fg·CFU-1 ·hr-1 ). The mass transfer rate constant from tumor to blood was 0.0125 hr-1 . Based on these measurements, this system has the capability to detect tumors as small as 0.12 g. These results demonstrate four essential mechanisms of this method: (i) preferential tumor colonization by bacteria, (ii) fluoromarker release in vivo, (iii) fluoromarker transport through tumor tissue and (iv) slow enough systemic clearance to enable measurement. This bacteria-based blood test would be minimally invasive and has the potential to identify previously undetectable microscopic tumors.
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Affiliation(s)
- Jan T Panteli
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA
| | - Nele Van Dessel
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA
| | - Neil S Forbes
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA
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11
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Thirumal Kumar D, Jerushah Emerald L, George Priya Doss C, Sneha P, Siva R, Charles Emmanuel Jebaraj W, Zayed H. Computational approach to unravel the impact of missense mutations of proteins (D2HGDH and IDH2) causing D-2-hydroxyglutaric aciduria 2. Metab Brain Dis 2018; 33:1699-1710. [PMID: 29987523 DOI: 10.1007/s11011-018-0278-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/20/2018] [Indexed: 01/28/2023]
Abstract
The 2-hydroxyglutaric aciduria (2-HGA) is a rare neurometabolic disorder that leads to the development of brain damage. It is classified into three categories: D-2-HGA, L-2-HGA, and combined D,L-2-HGA. The D-2-HGA includes two subtypes: type I and type II caused by the mutations in D2HGDH and IDH2 proteins, respectively. In this study, we studied six mutations, four in the D2HGDH (I147S, D375Y, N439D, and V444A) and two in the IDH2 proteins (R140G, R140Q). We performed in silico analysis to investigate the pathogenicity and stability changes of the mutant proteins using pathogenicity (PANTHER, PhD-SNP, SIFT, SNAP, and META-SNP) and stability (i-Mutant, MUpro, and iStable) predictors. All the mutations of both D2HGDH and IDH2 proteins were predicted as disease causing except V444A, which was predicted as neutral by SIFT. All the mutants were also predicted to be destabilizing the protein except the mutants D375Y and N439D. DSSP plugin of the PyMOL and Molecular Dynamics Simulations (MDS) were used to study the structural changes in the mutant proteins. In the case of D2HGDH protein, the mutations I147S and V444A that are positioned in the beta sheet region exhibited higher Root Mean Square Deviation (RMSD), decrease in compactness and number of intramolecular hydrogen bonds compared to the mutations N439D and D375Y that are positioned in the turn and loop region, respectively. While the mutants R140Q and R140QG that are positioned in the alpha helix region of the protein. MDS results revealed the mutation R140Q to be more destabilizing (higher RMSD values, decrease in compactness and number of intramolecular hydrogen bonds) compared to the mutation R140G of the IDH2 protein. This study is expected to serve as a platform for drug development against 2-HGA and pave the way for more accurate variant assessment and classification for patients with genetic diseases.
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Affiliation(s)
- D Thirumal Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - L Jerushah Emerald
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - C George Priya Doss
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| | - P Sneha
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - R Siva
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India
| | - W Charles Emmanuel Jebaraj
- Faculty of Biomedical Sciences, Technology and Research, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, 600116, India
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health and Sciences, Qatar University, Doha, Qatar.
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12
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Singh V, Biswas P. Estimating the mean first passage time of protein misfolding. Phys Chem Chem Phys 2018; 20:5692-5698. [PMID: 29410980 DOI: 10.1039/c7cp06918a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Most theoretical and experimental studies confirm that proteins fold in the time scale of microseconds to milliseconds, but the kinetics of the protein misfolding remains largely unexplored. The kinetics of unfolding-folding-misfolding equilibrium in proteins is formulated in the analytical framework of the Master equation. The folded, unfolded and the misfolded state are characterized in terms of their respective contacts. The Mean First Passage Time (MFPT) to acquire the misfolded conformation from the native or folded state is derived from this equation with different boundary conditions. The MFPT is found to be practically independent of the length of the protein, the number of native contacts and the rate constant for the misfolded to the folded state. The results obtained from the survival probability are directly correlated to the age of onset and appearance of misfolding diseases in humans.
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Affiliation(s)
- Vishal Singh
- Department of Chemistry, University of Delhi, Delhi-110007, India.
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13
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Li X, Tao Y, Murphy JW, Scherer AN, Lam TT, Marshall AG, Koleske AJ, Boggon TJ. The repeat region of cortactin is intrinsically disordered in solution. Sci Rep 2017; 7:16696. [PMID: 29196701 PMCID: PMC5711941 DOI: 10.1038/s41598-017-16959-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/19/2017] [Indexed: 01/14/2023] Open
Abstract
The multi-domain protein, cortactin, contains a 37-residue repeating motif that binds to actin filaments. This cortactin repeat region comprises 6½ similar copies of the motif and binds actin filaments. To better understand this region of cortactin, and its fold, we conducted extensive biophysical analysis. Size exclusion chromatography with multi-angle light scattering (SEC-MALS) reveals that neither constructs of the cortactin repeats alone or together with the adjacent helical region homo-oligomerize. Using circular dichroism (CD) we find that in solution the cortactin repeats resemble a coil-like intrinsically disordered protein. Small-angle X-ray scattering (SAXS) also indicates that the cortactin repeats are intrinsically unfolded, and the experimentally observed radius of gyration (Rg) is coincidental to that calculated by the program Flexible-Meccano for an unfolded peptide of this length. Finally, hydrogen-deuterium exchange mass spectrometry (HDX-MS) indicates that the domain contains limited hydrophobic core regions. These experiments therefore provide evidence that in solution the cortactin repeat region of cortactin is intrinsically disordered.
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Affiliation(s)
- Xiaofeng Li
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06520, USA.,Department of Pathology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Yeqing Tao
- Department of Chemistry, Florida State University, 600 W., College Avenue, Tallahassee, FL, 32306, USA.,Biopharmaceutical Analytical Sciences, Biopharm R&D, GlaxoSmithKline, 709 Swedeland Road, King of Prussia, PA, 19406, USA
| | - James W Murphy
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Alexander N Scherer
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - TuKiet T Lam
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.,Yale MS & Proteomics Resource, Yale University, New Haven, CT, 06520, USA
| | - Alan G Marshall
- Department of Chemistry, Florida State University, 600 W., College Avenue, Tallahassee, FL, 32306, USA.,Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL, 32310, USA
| | - Anthony J Koleske
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, 06520, USA. .,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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14
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Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering. Sci Rep 2017; 7:14865. [PMID: 29093501 PMCID: PMC5665942 DOI: 10.1038/s41598-017-14448-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/10/2017] [Indexed: 12/21/2022] Open
Abstract
The phosphoprotein (P) is the main and essential cofactor of the RNA polymerase (L) of non-segmented, negative‐strand RNA viruses. P positions the viral polymerase onto its nucleoprotein–RNA template and acts as a chaperone of the nucleoprotein (N), thereby preventing nonspecific encapsidation of cellular RNAs. The phosphoprotein of human metapneumovirus (HMPV) forms homotetramers composed of a stable oligomerization domain (Pcore) flanked by large intrinsically disordered regions (IDRs). Here we combined x-ray crystallography of Pcore with small angle x-ray scattering (SAXS)-based ensemble modeling of the full-length P protein and several of its fragments to provide a structural description of P that captures its dynamic character, and highlights the presence of varyingly stable structural elements within the IDRs. We discuss the implications of the structural properties of HMPV P for the assembly and functioning of the viral transcription/replication machinery.
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15
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Benny B, George Priya Doss C, Thirumal Kumar D, Asha Devi S. Assessing reproductive toxicity and antioxidant enzymes on beta asarone induced male Wistar albino rats: In vivo and computational analysis. Life Sci 2017; 173:150-160. [DOI: 10.1016/j.lfs.2016.08.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/07/2016] [Accepted: 08/23/2016] [Indexed: 01/14/2023]
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16
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Azim M, Malekpourkoupaei A, Ye W, Jemere AB, Harrison DJ. Evaluation of protein separation mechanism and pore size distribution in colloidal self-assembled nanoparticle sieves for on-chip protein sizing. Electrophoresis 2016; 38:342-349. [DOI: 10.1002/elps.201600339] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/30/2016] [Accepted: 10/01/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Mohammad Azim
- Department of Chemistry; University of Alberta; Edmonton Alberta Canada
| | | | - Wenmin Ye
- Department of Chemistry; University of Alberta; Edmonton Alberta Canada
| | - Abebaw B. Jemere
- National Institute for Nanotechnology; NRC; Edmonton Alberta Canada
| | - D. Jed Harrison
- Department of Chemistry; University of Alberta; Edmonton Alberta Canada
- National Institute for Nanotechnology; NRC; Edmonton Alberta Canada
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17
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Ranganathan S, Maji SK, Padinhateeri R. Defining a Physical Basis for Diversity in Protein Self-Assemblies Using a Minimal Model. J Am Chem Soc 2016; 138:13911-13922. [DOI: 10.1021/jacs.6b06433] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Srivastav Ranganathan
- Department of Biosciences
and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Samir K. Maji
- Department of Biosciences
and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Ranjith Padinhateeri
- Department of Biosciences
and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
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18
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Mendes LFS, Garcia AF, Kumagai PS, de Morais FR, Melo FA, Kmetzsch L, Vainstein MH, Rodrigues ML, Costa-Filho AJ. New structural insights into Golgi Reassembly and Stacking Protein (GRASP) in solution. Sci Rep 2016; 6:29976. [PMID: 27436376 PMCID: PMC4951691 DOI: 10.1038/srep29976] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 06/27/2016] [Indexed: 12/21/2022] Open
Abstract
Among all proteins localized in the Golgi apparatus, a two-PDZ (PSD95/DlgA/Zo-1) domain protein plays an important role in the assembly of the cisternae. This Golgi Reassembly and Stacking Protein (GRASP) has puzzled researchers due to its large array of functions and relevance in Golgi functionality. We report here a biochemical and biophysical study of the GRASP55/65 homologue in Cryptococcus neoformans (CnGRASP). Bioinformatic analysis, static fluorescence and circular dichroism spectroscopies, calorimetry, small angle X-ray scattering, solution nuclear magnetic resonance, size exclusion chromatography and proteolysis assays were used to unravel structural features of the full-length CnGRASP. We detected the coexistence of regular secondary structures and large amounts of disordered regions. The overall structure is less compact than a regular globular protein and the high structural flexibility makes its hydrophobic core more accessible to solvent. Our results indicate an unusual behavior of CnGRASP in solution, closely resembling a class of intrinsically disordered proteins called molten globule proteins. To the best of our knowledge, this is the first structural characterization of a full-length GRASP and observation of a molten globule-like behavior in the GRASP family. The possible implications of this and how it could explain the multiple facets of this intriguing class of proteins are discussed.
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Affiliation(s)
- Luís F. S. Mendes
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Assuero F. Garcia
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Patricia S. Kumagai
- Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Fabio R. de Morais
- Departamento de Física, Centro Multiusuário de Inovação Biomolecular, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Júlio Mesquita, São José do Rio Preto, Brazil
| | - Fernando A. Melo
- Departamento de Física, Centro Multiusuário de Inovação Biomolecular, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista Júlio Mesquita, São José do Rio Preto, Brazil
| | - Livia Kmetzsch
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Marilene H. Vainstein
- Centro de Biotecnologia, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Marcio L. Rodrigues
- Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Antonio J. Costa-Filho
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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19
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Karpowicz P, Osmulski PA, Witkowska J, Sikorska E, Giżyńska M, Belczyk-Ciesielska A, Gaczynska ME, Jankowska E. Interplay between Structure and Charge as a Key to Allosteric Modulation of Human 20S Proteasome by the Basic Fragment of HIV-1 Tat Protein. PLoS One 2015; 10:e0143038. [PMID: 26575189 PMCID: PMC4648528 DOI: 10.1371/journal.pone.0143038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/29/2015] [Indexed: 12/25/2022] Open
Abstract
The proteasome is a giant protease responsible for degradation of the majority of cytosolic proteins. Competitive inhibitors of the proteasome are used against aggressive blood cancers. However, broadening the use of proteasome-targeting drugs requires new mechanistic approaches to the enzyme's inhibition. In our previous studies we described Tat1 peptide, an allosteric inhibitor of the proteasome derived from a fragment of the basic domain of HIV-Tat1 protein. Here, we attempted to dissect the structural determinants of the proteasome inhibition by Tat1. Single- and multiple- alanine walking scans were performed. Tat1 analogs with stabilized beta-turn conformation at positions 4-5 and 8-9, pointed out by the molecular dynamics modeling and the alanine scan, were synthesized. Structure of Tat1 analogs were analyzed by circular dichroism, Fourier transform infrared and nuclear magnetic resonance spectroscopy studies, supplemented by molecular dynamics simulations. Biological activity tests and structural studies revealed that high flexibility and exposed positive charge are hallmarks of Tat1 peptide. Interestingly, stabilization of a beta-turn at the 8-9 position was necessary to significantly improve the inhibitory potency.
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Affiliation(s)
- Przemysław Karpowicz
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Paweł A. Osmulski
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Julia Witkowska
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Emilia Sikorska
- Department of Organic Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | - Małgorzata Giżyńska
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | | | - Maria E. Gaczynska
- Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Elżbieta Jankowska
- Department of Biomedical Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
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20
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ProTSAV: A protein tertiary structure analysis and validation server. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1864:11-9. [PMID: 26478257 DOI: 10.1016/j.bbapap.2015.10.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/26/2015] [Accepted: 10/14/2015] [Indexed: 01/06/2023]
Abstract
Quality assessment of predicted model structures of proteins is as important as the protein tertiary structure prediction. A highly efficient quality assessment of predicted model structures directs further research on function. Here we present a new server ProTSAV, capable of evaluating predicted model structures based on some popular online servers and standalone tools. ProTSAV furnishes the user with a single quality score in case of individual protein structure along with a graphical representation and ranking in case of multiple protein structure assessment. The server is validated on ~64,446 protein structures including experimental structures from RCSB and predicted model structures for CASP targets and from public decoy sets. ProTSAV succeeds in predicting quality of protein structures with a specificity of 100% and a sensitivity of 98% on experimentally solved structures and achieves a specificity of 88%and a sensitivity of 91% on predicted protein structures of CASP11 targets under 2Å.The server overcomes the limitations of any single server/method and is seen to be robust in helping in quality assessment. ProTSAV is freely available at http://www.scfbio-iitd.res.in/software/proteomics/protsav.jsp.
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21
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DasGupta D, Kaushik R, Jayaram B. From Ramachandran Maps to Tertiary Structures of Proteins. J Phys Chem B 2015; 119:11136-45. [DOI: 10.1021/acs.jpcb.5b02999] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Debarati DasGupta
- Department of Chemistry, ‡Supercomputing Facility for Bioinformatics & Computational Biology, and §Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India
| | - Rahul Kaushik
- Department of Chemistry, ‡Supercomputing Facility for Bioinformatics & Computational Biology, and §Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India
| | - B. Jayaram
- Department of Chemistry, ‡Supercomputing Facility for Bioinformatics & Computational Biology, and §Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India
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22
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Wicker-Planquart C, Ceres N, Jault JM. The C-terminal α-helix of YsxC is essential for its binding to 50S ribosome and rRNAs. FEBS Lett 2015; 589:2080-6. [PMID: 26103561 DOI: 10.1016/j.febslet.2015.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/01/2015] [Accepted: 06/09/2015] [Indexed: 11/28/2022]
Abstract
YsxC is an essential P-loop GTPase that interacts with the 50S subunit of the ribosome. The putative implication in ribosome binding of two basic clusters of YsxC, a conserved positively charged patch including R31, R116, H117 and K146 lying adjacent to the nucleotide-binding site, and the C-terminal alpha helix, was investigated. C-terminal truncation variants of YsxC were unable to bind to both ribosome and rRNAs, whereas mutations in the other cluster did not affect YsxC binding. Our results indicate that the basic C-terminal region of YsxC is required for its binding to the 50S ribosomal subunit.
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Affiliation(s)
- Catherine Wicker-Planquart
- CNRS, IBS, 6 rue Jules Horowitz, 38000 Grenoble, France; Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; CNRS, IBS, F-38027 Grenoble, France; CEA, DSV, IBS, F-38027 Grenoble, France.
| | - Nicoletta Ceres
- BMSSI, UMR 5086 CNRS/Université Claude Bernard Lyon I, France
| | - Jean-Michel Jault
- CNRS, IBS, 6 rue Jules Horowitz, 38000 Grenoble, France; Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; CNRS, IBS, F-38027 Grenoble, France; CEA, DSV, IBS, F-38027 Grenoble, France.
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23
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Balu R, Knott R, Cowieson NP, Elvin CM, Hill AJ, Choudhury NR, Dutta NK. Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin. Sci Rep 2015; 5:10896. [PMID: 26042819 PMCID: PMC4455251 DOI: 10.1038/srep10896] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 04/21/2015] [Indexed: 01/08/2023] Open
Abstract
Rec1-resilin is the first recombinant resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-resilin in aqueous solution. The structure of Rec1-resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-resilin in solution.
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Affiliation(s)
- Rajkamal Balu
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
| | - Robert Knott
- ANSTO, Private Mail Bag, Kirrawee, New South Wales 2232, Australia
| | - Nathan P. Cowieson
- Centre for Synchrotron Science, Monash University, Victoria 3800, Australia
| | - Christopher M. Elvin
- CSIRO Agriculture, Level 6, Queensland Bioscience Precinct, St Lucia, Queensland 4067, Australia
| | - Anita J. Hill
- CSIRO Manufacturing, Clayton, Victoria 3168, Australia
| | - Namita R. Choudhury
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
| | - Naba K. Dutta
- Ian Wark Research Institute, University of South Australia, Mawson Lakes campus, Mawson lakes, South Australia 5095, Australia
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24
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Jayaram B, Dhingra P, Mishra A, Kaushik R, Mukherjee G, Singh A, Shekhar S. Bhageerath-H: a homology/ab initio hybrid server for predicting tertiary structures of monomeric soluble proteins. BMC Bioinformatics 2014; 15 Suppl 16:S7. [PMID: 25521245 PMCID: PMC4290660 DOI: 10.1186/1471-2105-15-s16-s7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The advent of human genome sequencing project has led to a spurt in the number of protein sequences in the databanks. Success of structure based drug discovery severely hinges on the availability of structures. Despite significant progresses in the area of experimental protein structure determination, the sequence-structure gap is continually widening. Data driven homology based computational methods have proved successful in predicting tertiary structures for sequences sharing medium to high sequence similarities. With dwindling similarities of query sequences, advanced homology/ ab initio hybrid approaches are being explored to solve structure prediction problem. Here we describe Bhageerath-H, a homology/ ab initio hybrid software/server for predicting protein tertiary structures with advancing drug design attempts as one of the goals. RESULTS Bhageerath-H web-server was validated on 75 CASP10 targets which showed TM-scores ≥ 0.5 in 91% of the cases and Cα RMSDs ≤ 5 Å from the native in 58% of the targets, which is well above the CASP10 water mark. Comparison with some leading servers demonstrated the uniqueness of the hybrid methodology in effectively sampling conformational space, scoring best decoys and refining low resolution models to high and medium resolution. CONCLUSION Bhageerath-H methodology is web enabled for the scientific community as a freely accessible web server. The methodology is fielded in the on-going CASP11 experiment.
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25
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An16-resilin: an advanced multi-stimuli-responsive resilin-mimetic protein polymer. Acta Biomater 2014; 10:4768-4777. [PMID: 25107894 DOI: 10.1016/j.actbio.2014.07.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 07/21/2014] [Accepted: 07/29/2014] [Indexed: 11/21/2022]
Abstract
Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a resilin-mimetic protein, An16-resilin (An16), derived from the consensus sequence of resilin gene in the mosquito Anopheles gambiae. We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
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26
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Naqvi MA, Rauscher S, Pomès R, Rousseau D. The Conformational Ensemble of the β-Casein Phosphopeptide Reveals Two Independent Intrinsically Disordered Segments. Biochemistry 2014; 53:6402-8. [DOI: 10.1021/bi500107u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Muhammad Ali Naqvi
- Department
of Chemistry and Biology, Ryerson University, Toronto, Ontario M5B 2K3, Canada
| | - Sarah Rauscher
- Max Plank Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Régis Pomès
- Department
of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Molecular
Structure and Function, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Dérick Rousseau
- Department
of Chemistry and Biology, Ryerson University, Toronto, Ontario M5B 2K3, Canada
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27
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Mishra A, Rana PS, Mittal A, Jayaram B. D2N: Distance to the native. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1798-807. [DOI: 10.1016/j.bbapap.2014.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/03/2014] [Accepted: 07/15/2014] [Indexed: 12/26/2022]
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28
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Ahmed MH, Kellogg GE, Selley DE, Safo MK, Zhang Y. Predicting the molecular interactions of CRIP1a-cannabinoid 1 receptor with integrated molecular modeling approaches. Bioorg Med Chem Lett 2014; 24:1158-65. [PMID: 24461351 PMCID: PMC4353595 DOI: 10.1016/j.bmcl.2013.12.119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/26/2013] [Accepted: 12/29/2013] [Indexed: 12/14/2022]
Abstract
Cannabinoid receptors are a family of G-protein coupled receptors that are involved in a wide variety of physiological processes and diseases. One of the key regulators that are unique to cannabinoid receptors is the cannabinoid receptor interacting proteins (CRIPs). Among them CRIP1a was found to decrease the constitutive activity of the cannabinoid type-1 receptor (CB1R). The aim of this study is to gain an understanding of the interaction between CRIP1a and CB1R through using different computational techniques. The generated model demonstrated several key putative interactions between CRIP1a and CB1R, including the critical involvement of Lys130 in CRIP1a.
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Affiliation(s)
- Mostafa H Ahmed
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA; Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Dana E Selley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Martin K Safo
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Yan Zhang
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA.
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29
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Dhingra P, Jayaram B. A homology/ab initio hybrid algorithm for sampling near-native protein conformations. J Comput Chem 2013; 34:1925-36. [PMID: 23728619 DOI: 10.1002/jcc.23339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/09/2013] [Accepted: 04/21/2013] [Indexed: 12/19/2022]
Abstract
One of the major challenges for protein tertiary structure prediction strategies is the quality of conformational sampling algorithms, which can effectively and readily search the protein fold space to generate near-native conformations. In an effort to advance the field by making the best use of available homology as well as fold recognition approaches along with ab initio folding methods, we have developed Bhageerath-H Strgen, a homology/ab initio hybrid algorithm for protein conformational sampling. The methodology is tested on the benchmark CASP9 dataset of 116 targets. In 93% of the cases, a structure with TM-score ≥ 0.5 is generated in the pool of decoys. Further, the performance of Bhageerath-H Strgen was seen to be efficient in comparison with different decoy generation methods. The algorithm is web enabled as Bhageerath-H Strgen web tool which is made freely accessible for protein decoy generation (http://www.scfbio-iitd.res.in/software/Bhageerath-HStrgen1.jsp).
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Affiliation(s)
- Priyanka Dhingra
- Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
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30
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Capturing native/native like structures with a physico-chemical metric (pcSM) in protein folding. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1520-31. [PMID: 23665455 DOI: 10.1016/j.bbapap.2013.04.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/12/2013] [Accepted: 04/15/2013] [Indexed: 12/15/2022]
Abstract
Specification of the three dimensional structure of a protein from its amino acid sequence, also called a "Grand Challenge" problem, has eluded a solution for over six decades. A modestly successful strategy has evolved over the last couple of decades based on development of scoring functions (e.g. mimicking free energy) that can capture native or native-like structures from an ensemble of decoys generated as plausible candidates for the native structure. A scoring function must be fast enough in discriminating the native from unfolded/misfolded structures, and requires validation on a large data set(s) to generate sufficient confidence in the score. Here we develop a scoring function called pcSM that detects true native structure in the top 5 with 93% accuracy from an ensemble of candidate structures. If we eliminate the native from ensemble of decoys then pcSM is able to capture near native structure (RMSD<=5Ǻ) in top 10 with 86% accuracy. The parameters considered in pcSM are a C-alpha Euclidean metric, secondary structural propensity, surface areas and an intramolecular energy function. pcSM has been tested on 415 systems consisting 142,698 decoys (public and CASP-largest reported hitherto in literature). The average rank for the native is 2.38, a significant improvement over that existing in literature. In-silico protein structure prediction requires robust scoring technique(s). Therefore, pcSM is easily amenable to integration into a successful protein structure prediction strategy. The tool is freely available at http://www.scfbio-iitd.res.in/software/pcsm.jsp.
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31
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Birdsall RE, Koshel BM, Hua Y, Ratnayaka SN, Wirth MJ. Modeling of protein electrophoresis in silica colloidal crystals having brush layers of polyacrylamide. Electrophoresis 2013; 34:753-60. [PMID: 23229163 DOI: 10.1002/elps.201200413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/21/2012] [Indexed: 12/28/2022]
Abstract
Sieving of proteins in silica colloidal crystals of millimeter dimensions is characterized for particle diameters of nominally 350 and 500 nm, where the colloidal crystals are chemically modified with a brush layer of polyacrylamide. A model is developed that relates the reduced electrophoretic mobility to the experimentally measurable porosity. The model fits the data with no adjustable parameters for the case of silica colloidal crystals packed in capillaries, for which independent measurements of the pore radii were made from flow data. The model also fits the data for electrophoresis in a highly ordered colloidal crystal formed in a channel, where the unknown pore radius was used as a fitting parameter. Plate heights as small as 0.4 μm point to the potential for miniaturized separations. Band broadening increases as the pore radius approaches the protein radius, indicating that the main contribution to broadening is the spatial heterogeneity of the pore radius. The results quantitatively support the notion that sieving occurs for proteins in silica colloidal crystals, and facilitate design of new separations that would benefit from miniaturization.
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Affiliation(s)
- Robert E Birdsall
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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32
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Soni A, Pandey KM, Ray P, Jayaram B. Genomes to hits in silico - a country path today, a highway tomorrow: a case study of chikungunya. Curr Pharm Des 2013; 19:4687-700. [PMID: 23260020 PMCID: PMC3831887 DOI: 10.2174/13816128113199990379] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 12/17/2012] [Indexed: 12/11/2022]
Abstract
These are exciting times for bioinformaticians, computational biologists and drug designers with the genome and proteome sequences and related structural databases growing at an accelerated pace. The post-genomic era has triggered high expectations for a rapid and successful treatment of diseases. However, in this biological information rich and functional knowledge poor scenario, the challenges are indeed grand, no less than the assembly of the genome of the whole organism. These include functional annotation of genes, identification of druggable targets, prediction of three-dimensional structures of protein targets from their amino acid sequences, arriving at lead compounds for these targets followed by a transition from bench to bedside. We propose here a "Genome to Hits In Silico" strategy (called Dhanvantari) and illustrate it on Chikungunya virus (CHIKV). "Genome to hits" is a novel pathway incorporating a series of steps such as gene prediction, protein tertiary structure determination, active site identification, hit molecule generation, docking and scoring of hits to arrive at lead compounds. The current state of the art for each of the steps in the pathway is high-lighted and the feasibility of creating an automated genome to hits assembly line is discussed.
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Affiliation(s)
- Anjali Soni
- Department of Chemistry, Supercomputing Facility for Bioinformatics & Computational Biology, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India.
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33
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Pasi M, Lavery R, Ceres N. PaLaCe: A Coarse-Grain Protein Model for Studying Mechanical Properties. J Chem Theory Comput 2012; 9:785-93. [DOI: 10.1021/ct3007925] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Marco Pasi
- Bases Moléculaires
et Structurales des Systèmes
Infectieux, Univ. Lyon I/CNRS UMR 5086, IBCP, 7 Passage du Vercors,
69367 Lyon, France
| | - Richard Lavery
- Bases Moléculaires
et Structurales des Systèmes
Infectieux, Univ. Lyon I/CNRS UMR 5086, IBCP, 7 Passage du Vercors,
69367 Lyon, France
| | - Nicoletta Ceres
- Bases Moléculaires
et Structurales des Systèmes
Infectieux, Univ. Lyon I/CNRS UMR 5086, IBCP, 7 Passage du Vercors,
69367 Lyon, France
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34
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Sikorska E, Kwiatkowska A. Micelle-bound conformations of neurohypophyseal hormone analogues modified with a Cα-disubstituted residue: NMR and molecular modelling studies. J Biomol Struct Dyn 2012; 31:748-64. [PMID: 22908889 DOI: 10.1080/07391102.2012.709459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In this study, by applying a combined approach of NMR measurements and molecular modelling, the conformations and the interactions with membrane-like environment of five arginine vasopressin (AVP) or oxytocin (OT) analogues modified with Cα-disubstituted cis-1-amino-4-phenylcyclohexane-1-carboxylic acid in position 2 have been determined. In addition, the AVP analogues were prepared in N-acylated forms with various bulky acyl groups. All of the peptides studied interacted with the mixed dodecylphosphocholine:sodium dodecyl sulphate micelle, providing a model of biological membrane. A different polarities of the AVP- and OT-like peptides resulted in their different position relative to the micelle surface. Thus, the arrangement of the former was nearly perpendicular, whereas the latter was rather parallel to the micelle's surface. Moreover, the results of our studies have shown that the binding sites for antagonists may be overlapped with that for agonists, as well as it may be quite different. Nevertheless, the aromatic-aromatic contacts represent the most important interactions for antagonists, whereas the hydrophilic interactions seem to be crucial for agonists.
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Affiliation(s)
- Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952, Gdańsk, Poland.
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35
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Bhageerath—Targeting the near impossible: Pushing the frontiers of atomic models for protein tertiary structure prediction#. J CHEM SCI 2012. [DOI: 10.1007/s12039-011-0189-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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36
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Guimarães CRW, Mathiowetz AM, Shalaeva M, Goetz G, Liras S. Use of 3D Properties to Characterize Beyond Rule-of-5 Property Space for Passive Permeation. J Chem Inf Model 2012; 52:882-90. [DOI: 10.1021/ci300010y] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cristiano R. W. Guimarães
- Worldwide Medicinal Chemistry Department, Pfizer Global Research and Development, Eastern Point
Road, Groton, Connecticut 06340, United States
| | - Alan M. Mathiowetz
- Worldwide Medicinal Chemistry Department, Pfizer Global Research and Development, Eastern Point
Road, Groton, Connecticut 06340, United States
| | - Marina Shalaeva
- Worldwide Medicinal Chemistry Department, Pfizer Global Research and Development, Eastern Point
Road, Groton, Connecticut 06340, United States
| | - Gilles Goetz
- Worldwide Medicinal Chemistry Department, Pfizer Global Research and Development, Eastern Point
Road, Groton, Connecticut 06340, United States
| | - Spiros Liras
- Worldwide Medicinal Chemistry Department, Pfizer Global Research and Development, Eastern Point
Road, Groton, Connecticut 06340, United States
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37
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Mayer C, Slater L, Erat MC, Konrat R, Vakonakis I. Structural analysis of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) intracellular domain reveals a conserved interaction epitope. J Biol Chem 2012; 287:7182-9. [PMID: 22249178 PMCID: PMC3293552 DOI: 10.1074/jbc.m111.330779] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmodium falciparum-infected red blood cells adhere to endothelial cells, thereby obstructing the microvasculature. Erythrocyte adherence is directly associated with severe malaria and increased disease lethality, and it is mediated by the PfEMP1 family. PfEMP1 clustering in knob-like protrusions on the erythrocyte membrane is critical for cytoadherence, however the molecular mechanisms behind this system remain elusive. Here, we show that the intracellular domains of the PfEMP1 family (ATS) share a unique molecular architecture, which comprises a minimal folded core and extensive flexible elements. A conserved flexible segment at the ATS center is minimally restrained by the folded core. Yeast-two-hybrid data and a novel sequence analysis method suggest that this central segment contains a conserved protein interaction epitope. Interestingly, ATS in solution fails to bind the parasite knob-associated histidine-rich protein (KAHRP), an essential cytoadherence component. Instead, we demonstrate that ATS associates with PFI1780w, a member of the Plasmodium helical interspersed sub-telomeric (PHIST) family. PHIST domains are widespread in exported parasite proteins, however this is the first specific molecular function assigned to any variant of this family. We propose that PHIST domains facilitate protein interactions, and that the conserved ATS epitope may be targeted to disrupt the parasite cytoadherence system.
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Affiliation(s)
- Christina Mayer
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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38
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Sikorska E, Sobolewski D, Kwiatkowska A. Conformational preferences of proline derivatives incorporated into vasopressin analogues: NMR and molecular modelling studies. Chem Biol Drug Des 2012; 79:535-47. [PMID: 22226070 DOI: 10.1111/j.1747-0285.2012.01318.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this study, arginine vasopressin analogues modified with proline derivatives - indoline-2-carboxylic acid (Ica), (2S,4R)-4-(naphthalene-2-ylmethyl)pyrrolidine-2-carboxylic acid (Nmp), (2S,4S)-4-aminopyroglutamic acid (APy) and (2R,4S)-4-aminopyroglutamic acid, (Apy) - were examined using NMR spectroscopy and molecular modelling methods. The results have shown that Ica is involved in the formation of the cis peptide bond. Moreover, it reduces to a great extent the conformational flexibility of the peptide. In turn, incorporation of (2S,4R)-Nmp stabilizes the backbone conformation, which is heavily influenced by the pyrrolidine ring. However, the aromatic part of the Nmp side chain exhibits a high degree of conformational freedom. With analogues IV and V, introduction of the 4-aminopyroglumatic acid reduces locally conformational space of the peptides, but it also results in weaker interactions with the dodecylphosphocholine/sodium dodecyl sulphate micelle. Admittedly, both analogues are adsorbed on the micelle's surface but they do not penetrate into its core. With analogue V, the interactions between the peptide and the micelle seem to be so weak that conformational equilibrium is established between different bound states.
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Affiliation(s)
- Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland.
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39
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Singh T, Biswas D, Jayaram B. AADS--an automated active site identification, docking, and scoring protocol for protein targets based on physicochemical descriptors. J Chem Inf Model 2011; 51:2515-27. [PMID: 21877713 DOI: 10.1021/ci200193z] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here a robust automated active site detection, docking, and scoring (AADS) protocol for proteins with known structures. The active site finder identifies all cavities in a protein and scores them based on the physicochemical properties of functional groups lining the cavities in the protein. The accuracy realized on 620 proteins with sizes ranging from 100 to 600 amino acids with known drug active sites is 100% when the top ten cavity points are considered. These top ten cavity points identified are then submitted for an automated docking of an input ligand/candidate molecule. The docking protocol uses an all atom energy based Monte Carlo method. Eight low energy docked structures corresponding to different locations and orientations of the candidate molecule are stored at each cavity point giving 80 docked structures overall which are then ranked using an effective free energy function and top five structures are selected. The predicted structure and energetics of the complexes agree quite well with experiment when tested on a data set of 170 protein-ligand complexes with known structures and binding affinities. The AADS methodology is implemented on an 80 processor cluster and presented as a freely accessible, easy to use tool at http://www.scfbio-iitd.res.in/dock/ActiveSite_new.jsp .
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Affiliation(s)
- Tanya Singh
- Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
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40
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Cao B, Elber R. Computational exploration of the network of sequence flow between protein structures. Proteins 2010; 78:985-1003. [PMID: 19899165 DOI: 10.1002/prot.22622] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We investigate small sequence adjustments (of one or a few amino acids) that induce large conformational transitions between distinct and stable folds of proteins. Such transitions are intriguing from evolutionary and protein-design perspectives. They make it possible to search for ancient protein structures or to design protein switches that flip between folds and functions. A network of sequence flow between protein folds is computed for representative structures of the Protein Data Bank. The computed network is dense, on an average each structure is connected to tens of other folds. Proteins that attract sequences from a higher than expected number of neighboring folds are more likely to be enzymes and alpha/beta fold. The large number of connections between folds may reflect the need of enzymes to adjust their structures for alternative substrates. The network of the Cro family is discussed, and we speculate that capacity is an important factor (but not the only one) that determines protein evolution. The experimentally observed flip from all alpha to alpha + beta fold is examined by the network tools. A kinetic model for the transition of sequences between the folds (with only protein stability in mind) is proposed. Proteins 2010. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Baoqiang Cao
- Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, USA
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41
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Májek P, Elber R. A coarse-grained potential for fold recognition and molecular dynamics simulations of proteins. Proteins 2009; 76:822-36. [PMID: 19291741 DOI: 10.1002/prot.22388] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A coarse-grained potential for protein simulations and fold ranking is presented. The potential is based on a two-point model of individual amino acids and a specific implementation of hydrogen bonding. Parameters are determined for distance dependent pair interactions, pseudo bonds, angles, and torsions. A scaling factor for a hydrogen bonding term is also determined. Iterative sampling for 4867 proteins reproduces distributions of internal coordinates and distances observed in the Protein Data Bank. The adjustment of the potential and resampling are in the spirit of the generalized ensemble approach. No native structure information (e.g., secondary structure) is used in the calculation of the potential or in the simulation of a particular protein. The potential is subject to two tests as follows: (i) simulations of 956 globular proteins in the neighborhood of their native folds (these proteins were not used in the training set) and (ii) discrimination between native and decoy structures for 2470 proteins with 305,000 decoys and the "Decoys 'R' Us" dataset. In the first test, 58% of tested proteins stay within 5 A from the native fold in Molecular Dynamics simulations of more than 20 nanoseconds using the new potential. The potential is also useful in differentiating between correct and approximate folds providing significant signal for structure prediction algorithms. Sampling with the potential consistently regenerates the distribution of distances and internal coordinates it learned. Nevertheless, during Molecular Dynamics simulations structures are found that reproduce the learned distributions but are far from the native fold.
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Affiliation(s)
- Peter Májek
- Department of Computer Science, Upson Hall 4130, Cornell University, Ithaca, New York 14853-7501, USA
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42
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Pechmann S, Levy ED, Tartaglia GG, Vendruscolo M. Physicochemical principles that regulate the competition between functional and dysfunctional association of proteins. Proc Natl Acad Sci U S A 2009; 106:10159-64. [PMID: 19502422 PMCID: PMC2700930 DOI: 10.1073/pnas.0812414106] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Indexed: 01/31/2023] Open
Abstract
To maintain protein homeostasis, a variety of quality control mechanisms, such as the unfolded protein response and the heat shock response, enable proteins to fold and to assemble into functional complexes while avoiding the formation of aberrant and potentially harmful aggregates. We show here that a complementary contribution to the regulation of the interactions between proteins is provided by the physicochemical properties of their amino acid sequences. The results of a systematic analysis of the protein-protein complexes in the Protein Data Bank (PDB) show that interface regions are more prone to aggregate than other surface regions, indicating that many of the interactions that promote the formation of functional complexes, including hydrophobic and electrostatic forces, can potentially also cause abnormal intermolecular association. We also show, however, that aggregation-prone interfaces are prevented from triggering uncontrolled assembly by being stabilized into their functional conformations by disulfide bonds and salt bridges. These results indicate that functional and dysfunctional association of proteins are promoted by similar forces but also that they are closely regulated by the presence of specific interactions that stabilize native states.
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Affiliation(s)
- Sebastian Pechmann
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - Emmanuel D. Levy
- Laboratory of Molecular Biology, Medical Research Council, Hills Road, Cambridge CB2 0QH, United Kingdom
| | - Gian Gaetano Tartaglia
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; and
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Madhusmita S, Singh H, Karlapalem K, Mitra A. A real valued Genetic Algorithm for generating native like structure of small globular protein. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:1359-62. [PMID: 19162920 DOI: 10.1109/iembs.2008.4649417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Predicting the 3D native conformation of a protein given the amino acid sequence is known as protein structure prediction (PSP) problem and is one of the greatest challenges of computational biology. The current work uses a real valued Genetic Algorithm (GA), a powerful variate of GA to simulate the PSP problem. This algorithm consists of basic evolutionary operators and a fitness vector. The fitness vector is designed by combining a set of knowledge based biophysical filters viz. persistence length, radius of gyration, packing fraction, hydrophobicity ratio and irregularity index of phi and psi. This vector converts all these biophysical measures into a real value by using specific weights or factors. The algorithm has been validated on six known globular proteins, with their length varying from 17-61 residues and total number of helices and strands in the range of 2-4. For all the test protein the algorithm converges rapidly and the converged structure shows a backbone RMSD (root mean square deviation) of 3-6A as compared to the native structure.
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Affiliation(s)
- S Madhusmita
- Centre for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad-500032, India
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44
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Nairn KM, Lyons RE, Mulder RJ, Mudie ST, Cookson DJ, Lesieur E, Kim M, Lau D, Scholes FH, Elvin CM. A synthetic resilin is largely unstructured. Biophys J 2008; 95:3358-3365. [PMID: 18586853 PMCID: PMC2547447 DOI: 10.1529/biophysj.107.119107] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023] Open
Abstract
Proresilin is the precursor protein for resilin, an extremely elastic, hydrated, cross-linked insoluble protein found in insects. We investigated the secondary-structure distribution in solution of a synthetic proresilin (AN16), based on 16 units of the consensus proresilin repeat from Anopheles gambiae. Raman spectroscopy was used to verify that the secondary-structure distributions in cross-linked AN16 resilin and in AN16 proresilin are similar, and hence that solution techniques (such as NMR and circular dichroism) may be used to gain information about the structure of the cross-linked solid. The synthetic proresilin AN16 is an intrinsically unstructured protein, displaying under native conditions many of the characteristics normally observed in denatured proteins. There are no apparent alpha-helical or beta-sheet features in the NMR spectra, and the majority of backbone protons and carbons exhibit chemical shifts characteristic of random-coil configurations. Relatively few peaks are observed in the nuclear Overhauser effect spectra, indicating that overall the protein is dynamic and unstructured. The radius of gyration of AN16 corresponds to the value expected for a denatured protein of similar chain length. This high degree of disorder is also consistent with observed circular dichroism and Raman spectra. The temperature dependences of the NH proton chemical shifts were also measured. Most values were indicative of protons exposed to water, although smaller dependences were observed for glycine and alanine within the Tyr-Gly-Ala-Pro sequence conserved in all resilins found to date, which is the site of dityrosine cross-link formation. This result implies that these residues are involved in hydrogen bonds, possibly to enable efficient self-association and subsequent cross-linking. The beta-spiral model for elastic proteins, where the protein is itself shaped like a spring, is not supported by the results for AN16. Both the random-network elastomer model and the sliding beta-turn model are consistent with the data. The results indicate a flat energy landscape for AN16, with very little energy required to switch between conformations. This ease of switching is likely to lead to the extremely low energy loss on deformation of resilin.
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Affiliation(s)
- Kate M Nairn
- CSIRO Materials Science and Engineering, Clayton, Victoria, Australia.
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45
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Wu GA, Coutsias EA, Dill KA. Iterative assembly of helical proteins by optimal hydrophobic packing. Structure 2008; 16:1257-66. [PMID: 18682227 PMCID: PMC2629734 DOI: 10.1016/j.str.2008.04.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 03/26/2008] [Accepted: 04/06/2008] [Indexed: 11/21/2022]
Abstract
We present a method for the computer-based iterative assembly of native-like tertiary structures of helical proteins from alpha-helical fragments. For any pair of helices, our method, called MATCHSTIX, first generates an ensemble of possible relative orientations of the helices with various ways to form hydrophobic contacts between them. Those conformations having steric clashes, or a large radius of gyration of hydrophobic residues, or with helices too far separated to be connected by the intervening linking region, are discarded. Then, we attempt to connect the two helical fragments by using a robotics-based loop-closure algorithm. When loop closure is feasible, the algorithm generates an ensemble of viable interconnecting loops. After energy minimization and clustering, we use a representative set of conformations for further assembly with the remaining helices, adding one helix at a time. To efficiently sample the conformational space, the order of assembly generally proceeds from the pair of helices connected by the shortest loop, followed by joining one of its adjacent helices, always proceeding with the shorter connecting loop. We tested MATCHSTIX on 28 helical proteins each containing up to 5 helices and found it to heavily sample native-like conformations. The average rmsd of the best conformations for the 17 helix-bundle proteins that have 2 or 3 helices is less than 2 A; errors increase somewhat for proteins containing more helices. Native-like states are even more densely sampled when disulfide bonds are known and imposed as restraints. We conclude that, at least for helical proteins, if the secondary structures are known, this rapid rigid-body maximization of hydrophobic interactions can lead to small ensembles of highly native-like structures. It may be useful for protein structure prediction.
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Affiliation(s)
- G. Albert Wu
- Department of Pharmaceutical Chemistry, University of California in San Francisco, San Francisco, California 94143-2240
| | - Evangelos A. Coutsias
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico 87131
| | - Ken A. Dill
- Department of Pharmaceutical Chemistry, University of California in San Francisco, San Francisco, California 94143-2240
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46
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Thukral L, Shenoy SR, Bhushan K, Jayaram B. ProRegIn: A regularity index for the selection of native-like tertiary structures of proteins. J Biosci 2007; 32:71-81. [PMID: 17426381 DOI: 10.1007/s12038-007-0007-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Automated protein tertiary structure prediction from sequence information alone remains an elusive goal to computational prescriptions. Dividing the problem into three stages viz. secondary structure prediction, generation of plausible main chain loop dihedrals and side chain dihedral optimization, considerable progress has been achieved in our laboratory (http://www.scfbio-iitd.res.in/bhageerath/index.jsp) and elsewhere for proteins with less than 100 amino acids. As a part of our on-going efforts in this direction and to facilitate tertiary structure selection/rejection in containing the combinatorial explosion of trial structures for a specified amino acid sequence, we describe here a web-enabled tool ProRegIn (Protein Regularity Index) developed based on the regularity in the Phi, Psi dihedral angles of the amino acids that constitute loop regions. We have analysed the dihedrals in loop regions in a non-redundant dataset of 7351 proteins drawn from the Protein Data Bank and categorized them as helix-like or sheet-like (regular) or irregular. We noticed that the regularity thus defined exceeds 86% for Phi barring glycine and 70% for Psi for all the amino acid side chains including glycine, compelling us to reexamine the conventional view that loops are irregular regions structurally. The regularity index is presented here as a simple tool that finds its application in protein structure analysis as a discriminatory scoring function for rapid screening before the more compute intensive atomic level energy calculations could be undertaken. The tool is made freely accessible over the internet at www.scfbio-iitd.res.in/software/proregin.jsp.
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Affiliation(s)
- Lipi Thukral
- Department of Chemistry and Supercomputing Facility for Bioinformatics and Computational Biology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016, India
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47
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Jayaram B, Bhushan K, Shenoy SR, Narang P, Bose S, Agrawal P, Sahu D, Pandey V. Bhageerath: an energy based web enabled computer software suite for limiting the search space of tertiary structures of small globular proteins. Nucleic Acids Res 2006; 34:6195-204. [PMID: 17090600 PMCID: PMC1693886 DOI: 10.1093/nar/gkl789] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We describe here an energy based computer software suite for narrowing down the search space of tertiary structures of small globular proteins. The protocol comprises eight different computational modules that form an automated pipeline. It combines physics based potentials with biophysical filters to arrive at 10 plausible candidate structures starting from sequence and secondary structure information. The methodology has been validated here on 50 small globular proteins consisting of 2–3 helices and strands with known tertiary structures. For each of these proteins, a structure within 3–6 Å RMSD (root mean square deviation) of the native has been obtained in the 10 lowest energy structures. The protocol has been web enabled and is accessible at .
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Affiliation(s)
- B Jayaram
- Department of Chemistry and Supercomputing Facility for Bioinformatics and Computational Biology, Indian Institute of Technology Delhi Hauz Khas, New Delhi 110 016, India.
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Narang P, Bhushan K, Bose S, Jayaram B. Protein Structure Evaluation using an All-Atom Energy Based Empirical Scoring Function. J Biomol Struct Dyn 2006; 23:385-406. [PMID: 16363875 DOI: 10.1080/07391102.2006.10531234] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Arriving at the native conformation of a polypeptide chain characterized by minimum most free energy is a problem of long standing interest in protein structure prediction endeavors. Owing to the computational requirements in developing free energy estimates, scoring functions--energy based or statistical--have received considerable renewed attention in recent years for distinguishing native structures of proteins from non-native like structures. Several cleverly designed decoy sets, CASP (Critical Assessment of Techniques for Protein Structure Prediction) structures and homology based internet accessible three dimensional model builders are now available for validating the scoring functions. We describe here an all-atom energy based empirical scoring function and examine its performance on a wide series of publicly available decoys. Barring two protein sequences where native structure is ranked second and seventh, native is identified as the lowest energy structure in 67 protein sequences from among 61,659 decoys belonging to 12 different decoy sets. We further illustrate a potential application of the scoring function in bracketing native-like structures of two small mixed alpha/beta globular proteins starting from sequence and secondary structural information. The scoring function has been web enabled at www.scfbio-iitd.res.in/utility/proteomics/energy.jsp.
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Affiliation(s)
- Pooja Narang
- Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi - 110016, India.
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