1
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Gul SS, Zardawi FM, Abdulkareem AA, Shaikh MS, Al-Rawi NH, Zafar MS. Efficacy of MMP-8 Level in Gingival Crevicular Fluid to Predict the Outcome of Nonsurgical Periodontal Treatment: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19053131. [PMID: 35270821 PMCID: PMC8910039 DOI: 10.3390/ijerph19053131] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 02/01/2023]
Abstract
Purpose: To explore whether baseline matrix metalloproteinase (MMP)-8 level in gingival crevicular fluid (GCF) (exposure) can predict the outcome (reduction in probing pocket depth (PPD) (outcome)) of nonsurgical periodontal therapy (NSPT) (manual or ultrasonic or both) in patients with periodontitis (population/problem) after 3 months. Methods: Six databases (PubMed, Cochrane library, ProQuest, Ovid, Scopus, EBSCO) were searched for relevant articles published until 30 July 2021. Retrieved articles were passed through a three-phase filtration process on the basis of the eligibility criteria. The primary outcome was the change in PPD after 3 months. Quality of the selected articles was assessed using Cochrane Risk of Bias tool (RoB2) and Risk of Bias In Non-Randomized Studies of Interventions (ROBINS-I) tools. Results: From 1306 articles, five were selected for analysis. The results showed high variations in the level of GCF MMP-8 level at baseline. The average amount of reduction in PPD was 1.20 and 2.30 mm for pockets with initial depth of 4−6 mm and >6 mm, respectively. Conclusion: On the basis of available evidence, it was not possible to reach a consensus on the ability of baseline GCF MMP-8 to forecast the outcome of NSPT. This could have been due to variation in clinical and laboratory techniques used. However, consistency in mean PPD reduction after 3 months was shown.
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Affiliation(s)
- Sarhang Sarwat Gul
- Department of Periodontics, College of Dentistry, University of Sulaimani, Sulaymaniyah 46001, Iraq;
- Correspondence:
| | - Faraedon Mostafa Zardawi
- Department of Periodontics, College of Dentistry, University of Sulaimani, Sulaymaniyah 46001, Iraq;
| | - Ali Abbas Abdulkareem
- Department of Periodontics, College of Dentistry, University of Baghdad, Baghdad 10011, Iraq;
| | - Muhammad Saad Shaikh
- Department of Oral Biology, Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University, Karachi 75510, Pakistan;
| | - Natheer Hashim Al-Rawi
- Department of Oral & Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates;
| | - Muhammad Sohail Zafar
- Department of Restorative Dentistry, College of Dentistry, Taibah University, Al Madina, Al Munawwarra 41311, Saudi Arabia;
- Department of Dental Materials, Islamic International Dental College, Riphah International University, Islamabad 44000, Pakistan
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2
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Harnden KA, Roy A, Hosseinzadeh P. Overview of Methods for Purification and Characterization of Metalloproteins. Curr Protoc 2021; 1:e234. [PMID: 34436821 DOI: 10.1002/cpz1.234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metalloproteins make up one third of all proteins and perform some of the most essential reactions on earth. The unique properties of the metal ions within these proteins, and in particular of redox-active metal ions, enables the use of a number of characterization techniques. It also necessitates unique considerations in terms of purification and characterization. In this overview, we describe the considerations and methods used for metalloprotein purification and characterization. © 2021 Wiley Periodicals LLC.
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Affiliation(s)
| | - Anindya Roy
- University of Washington, Department of Biochemistry, Institute for Protein Design, Seattle, Washington
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3
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Veselý L, Susrisweta B, Heger D. Making good's buffers good for freezing: The acidity changes and their elimination via mixing with sodium phosphate. Int J Pharm 2021; 593:120128. [PMID: 33271311 DOI: 10.1016/j.ijpharm.2020.120128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
Solutions of three Good's buffers (HEPES, MOPS, and MES), both pure and mixed with sodium phosphate buffers (Na-P), are investigated in terms of the freezing-induced acidity changes in their operational pH ranges. The Good's buffers have the tendency to basify upon freezing and, more intensively, at lower pHs. The acidity varies most prominently in MES, where the change may reach the value of two. Importantly, the Good's buffers are shown to mitigate the strong acidification in the Na-P buffer. Diverse concentrations of the Good's buffers are added to cancel out the strong, freezing-induced acidity drop in 50 mM Na-P that markedly contributes to the solution's acidity; the relevant values are 3 mM HEPES, 10 mM MOPS, and 80 mM MES. These buffer blends are therefore proposed to be applied in maintaining approximately the acidity of solutions even after the freezing process and, as such, should limit the stresses for frozen chemicals and biochemicals.
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Affiliation(s)
- Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Behera Susrisweta
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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4
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Sardar S, Weitz A, Hendrich MP, Pierce BS. Outer-Sphere Tyrosine 159 within the 3-Mercaptopropionic Acid Dioxygenase S-H-Y Motif Gates Substrate-Coordination Denticity at the Non-Heme Iron Active Site. Biochemistry 2019; 58:5135-5150. [PMID: 31750652 PMCID: PMC10071547 DOI: 10.1021/acs.biochem.9b00674] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thiol dioxygenases are non-heme mononuclear iron enzymes that catalyze the O2-dependent oxidation of free thiols (-SH) to produce the corresponding sulfinic acid (-SO2-). Regardless of the phylogenic domain, the active site for this enzyme class is typically comprised of two major features: (1) a mononuclear ferrous iron coordinated by three protein-derived histidines and (2) a conserved sequence of outer Fe-coordination-sphere amino acids (Ser-His-Tyr) spatially adjacent to the iron site (∼3 Å). Here, we utilize a promiscuous 3-mercaptopropionic acid dioxygenase cloned from Azotobacter vinelandii (Av MDO) to explore the function of the conserved S-H-Y motif. This enzyme exhibits activity with 3-mercaptopropionic acid (3mpa), l-cysteine (cys), as well as several other thiol-bearing substrates, thus making it an ideal system to study the influence of residues within the highly conserved S-H-Y motif (H157 and Y159) on substrate specificity and reactivity. The pKa values for these residues were determined by pH-dependent steady-state kinetics, and their assignments verified by comparison to H157N and Y159F variants. Complementary electron paramagnetic resonance and Mössbauer studies demonstrate a network of hydrogen bonds connecting H157-Y159 and Fe-bound ligands within the enzymatic Fe site. Crucially, these experiments suggest that the hydroxyl group of Y159 hydrogen bonds to Fe-bound NO and, by extension, Fe-bound oxygen during native catalysis. This interaction alters both the NO binding affinity and rhombicity of the 3mpa-bound iron-nitrosyl site. In addition, Fe coordination of cys is switched from thiolate only to bidentate (thiolate/amine) for the Y159F variant, indicating that perturbations within the S-H-Y proton relay network also influence cys Fe binding denticity.
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Affiliation(s)
- Sinjinee Sardar
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , 700 Planetarium Place , Arlington , Texas 76019 , United States
| | - Andrew Weitz
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Michael P Hendrich
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Brad S Pierce
- Department of Chemistry and Biochemistry , University of Alabama , 250 Hackberry Lane , Tuscaloosa , Alabama 35487 , United States
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5
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Padhiar AA, Chanda W, Joseph TP, Guo X, Liu M, Sha L, Batool S, Gao Y, Zhang W, Huang M, Zhong M. Comparative study to develop a single method for retrieving wide class of recombinant proteins from classical inclusion bodies. Appl Microbiol Biotechnol 2018; 102:2363-2377. [PMID: 29387954 DOI: 10.1007/s00253-018-8754-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/28/2017] [Accepted: 12/30/2017] [Indexed: 11/30/2022]
Abstract
The formation of inclusion bodies (IBs) is considered as an Achilles heel of heterologous protein expression in bacterial hosts. Wide array of techniques has been developed to recover biochemically challenging proteins from IBs. However, acquiring the active state even from the same protein family was found to be an independent of single established method. Here, we present a new strategy for the recovery of wide sub-classes of recombinant protein from harsh IBs. We found that numerous methods and their combinations for reducing IB formation and producing soluble proteins were not effective, if the inclusion bodies were harsh in nature. On the other hand, different practices with mild solubilization buffers were able to solubilize IBs completely, yet the recovery of active protein requires large screening of refolding buffers. With the integration of previously reported mild solubilization techniques, we proposed an improved method, which comprised low sarkosyl concentration, ranging from 0.05 to 0.1% coupled with slow freezing (- 1 °C/min) and fast thaw (room temperature), resulting in greater solubility and the integrity of solubilized protein. Dilution method was employed with single buffer to restore activity for every sub-class of recombinant protein. Results showed that the recovered protein's activity was significantly higher compared with traditional solubilization/refolding approach. Solubilization of IBs by the described method was proved milder in nature, which restored native-like conformation of proteins within IBs.
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Affiliation(s)
- Arshad Ahmed Padhiar
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China.,Department of Biosciences, Faculty of Science, Barrett Hodgson University, Karachi, Pakistan
| | - Warren Chanda
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Thomson Patrick Joseph
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Xuefang Guo
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Min Liu
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Li Sha
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Samana Batool
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Yifan Gao
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Wei Zhang
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China
| | - Min Huang
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China.
| | - Mintao Zhong
- Department of Microbiology, Basic Medical Sciences, Dalian Medical University, 9 Western Section, Lvshun South Road, Lvshunkou District, Dalian, 116044, China.
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6
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Yu Y, Petrik ID, Chacón KN, Hosseinzadeh P, Chen H, Blackburn NJ, Lu Y. Effect of circular permutation on the structure and function of type 1 blue copper center in azurin. Protein Sci 2017; 26:218-226. [PMID: 27759897 PMCID: PMC5275729 DOI: 10.1002/pro.3071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/13/2016] [Accepted: 10/14/2016] [Indexed: 11/10/2022]
Abstract
Type 1 copper (T1Cu) proteins are electron transfer (ET) proteins involved in many important biological processes. While the effects of changing primary and secondary coordination spheres in the T1Cu ET function have been extensively studied, few report has explored the effect of the overall protein structural perturbation on active site configuration or reduction potential of the protein, even though the protein scaffold has been proposed to play a critical role in enforcing the entatic or "rack-induced" state for ET functions. We herein report circular permutation of azurin by linking the N- and C-termini and creating new termini in the loops between 1st and 2nd β strands or between 3rd and 4th β strands. Characterization by electronic absorption, electron paramagnetic spectroscopies, as well as crystallography and cyclic voltammetry revealed that, while the overall structure and the primary coordination sphere of the circular permutated azurins remain the same as those of native azurin, their reduction potentials increased by 18 and 124 mV over that of WTAz. Such increases in reduction potentials can be attributed to subtle differences in the hydrogen-bonding network in secondary coordination sphere around the T1Cu center.
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Affiliation(s)
- Yang Yu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin300308China
| | - Igor D. Petrik
- Department of Chemistry, University of Illinois at Urbana‐ChampaignUrbanaIllinois61801
| | | | - Parisa Hosseinzadeh
- Department of BiochemistryUniversity of Illinois at Urbana‐ChampaignUrbanaIllinois61801
| | - Honghui Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of SciencesTianjin300308China
- Tianjin University of Science and TechnologyTianjin300457China
| | - Ninian J. Blackburn
- Institute of Environmental Health, Oregon Health and Science UniversityPortlandOregon97239
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana‐ChampaignUrbanaIllinois61801
- Department of BiochemistryUniversity of Illinois at Urbana‐ChampaignUrbanaIllinois61801
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7
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Zbacnik TJ, Holcomb RE, Katayama DS, Murphy BM, Payne RW, Coccaro RC, Evans GJ, Matsuura JE, Henry CS, Manning MC. Role of Buffers in Protein Formulations. J Pharm Sci 2016; 106:713-733. [PMID: 27894967 DOI: 10.1016/j.xphs.2016.11.014] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/25/2016] [Accepted: 11/17/2016] [Indexed: 12/19/2022]
Abstract
Buffers comprise an integral component of protein formulations. Not only do they function to regulate shifts in pH, they also can stabilize proteins by a variety of mechanisms. The ability of buffers to stabilize therapeutic proteins whether in liquid formulations, frozen solutions, or the solid state is highlighted in this review. Addition of buffers can result in increased conformational stability of proteins, whether by ligand binding or by an excluded solute mechanism. In addition, they can alter the colloidal stability of proteins and modulate interfacial damage. Buffers can also lead to destabilization of proteins, and the stability of buffers themselves is presented. Furthermore, the potential safety and toxicity issues of buffers are discussed, with a special emphasis on the influence of buffers on the perceived pain upon injection. Finally, the interaction of buffers with other excipients is examined.
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Affiliation(s)
| | - Ryan E Holcomb
- LegacyBioDesign LLC, Johnstown, Colorado 80534; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
| | - Derrick S Katayama
- LegacyBioDesign LLC, Johnstown, Colorado 80534; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
| | - Brian M Murphy
- LegacyBioDesign LLC, Johnstown, Colorado 80534; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
| | - Robert W Payne
- LegacyBioDesign LLC, Johnstown, Colorado 80534; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
| | | | | | | | - Charles S Henry
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523
| | - Mark Cornell Manning
- LegacyBioDesign LLC, Johnstown, Colorado 80534; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523.
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8
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Wright JJ, Salvadori E, Bridges HR, Hirst J, Roessler MM. Small-volume potentiometric titrations: EPR investigations of Fe-S cluster N2 in mitochondrial complex I. J Inorg Biochem 2016; 162:201-206. [DOI: 10.1016/j.jinorgbio.2016.04.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
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9
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Krausková Ľ, Procházková J, Klašková M, Filipová L, Chaloupková R, Malý S, Damborský J, Heger D. Suppression of protein inactivation during freezing by minimizing pH changes using ionic cryoprotectants. Int J Pharm 2016; 509:41-49. [PMID: 27224008 DOI: 10.1016/j.ijpharm.2016.05.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
Freezing and lyophilization are often used for stabilization of biomolecules; however, this sometimes results in partial degradation and loss of biological function in these molecules. In this study we examined the effect of freezing-induced acidity changes on denaturation of the model enzyme haloalkane dehalogenase under various experimental conditions. The effective local pH of frozen solutions is shown to be the key causal factor in protein stability. To preserve the activity of frozen-thawed enzymes, acidity changes were prevented by the addition of an ionic cryoprotectant, a compound which counteracts pH changes during freezing due to selective incorporation of its ions into the ice. This approach resulted in complete recovery of enzyme activity after multiple freeze-thaw cycles. We propose the utilization of ionic cryoprotectants as a new and effective cryopreservation method in research laboratories as well as in industrial processes.
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Affiliation(s)
- Ľubica Krausková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Jitka Procházková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Martina Klašková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Lenka Filipová
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Radka Chaloupková
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Stanislav Malý
- Central Institute for Supervising and Testing in Agriculture, Hroznová 2, CZ-656 06, Czech Republic
| | - Jiří Damborský
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic.
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10
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Stanyon HF, Patel K, Begum N, Viles JH. Copper(II) sequentially loads onto the N-terminal amino group of the cellular prion protein before the individual octarepeats. Biochemistry 2014; 53:3934-99. [PMID: 24878028 DOI: 10.1021/bi500643b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cellular prion protein (PrPC) binds to Cu2+ ions in vivo, and a misfolded form of PrPC is responsible for a range of transmissible spongiform encephalopathies. Recently, disruption of Cu2+ homeostasis in mice has been shown to impart resistance to scrapie infection. Using full-length PrPC and model peptide fragments, we monitor the sequential loading of Cu2+ ions onto PrPC using visible circular dichroism. We show the N-terminal amino group of PrPC is not the principal binding site for Cu2+; however, surprisingly, it has an affinity for Cu2+ tighter than that of the individual octarepeat binding sites present within PrPC. We re-evaluate what is understood about the sequential loading of Cu2+ onto the full-length protein and show for the first time that Cu2+ loads onto the N-terminal amino group before the single octarepeat binding sites.
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11
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Ullrich SJ, Glaubitz C. Perspectives in enzymology of membrane proteins by solid-state NMR. Acc Chem Res 2013; 46:2164-71. [PMID: 23745719 DOI: 10.1021/ar4000289] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Membrane proteins catalyze reactions at the cell membrane and facilitate thetransport of molecules or signals across the membrane. Recently researchers have made great progress in understanding the structural biology of membrane proteins, mainly based on X-ray crystallography. In addition, the application of complementary spectroscopic techniques has allowed researchers to develop a functional understanding of these proteins. Solid-state NMR has become an indispensable tool for the structure-function analysis of insoluble proteins and protein complexes. It offers the possibility of investigating membrane proteins directly in their environment, which provides essential information about the intrinsic coupling of protein structure and functional dynamics within the lipid bilayer. However, to date, researchers have hardly explored the enzymology of mem-brane proteins. In this Account, we review the perspectives for investigating membrane-bound enzymes by solid-state NMR. Understanding enzyme mechanisms requires access to kinetic parameters, structural analysis of the catalytic center, knowledge of the 3D structure and methods to follow the structural dynamics of the enzyme during the catalytic cycle. In principle, solid-state NMR can address all of these issues. Researchers can characterize the enzyme kinetics by observing substrate turnover within the membrane or at the membrane interphase in a time-resolved fashion as shown for diacylglycerol kinase. Solid-state NMR has also provided a mechanistic understanding of soluble enzymes including triosephosphate isomerase (TIM) and different metal-binding proteins, which demonstrates a promising perspective also for membrane proteins. The increasing availability of high magnetic fields and the development of new experimental schemes and computational protocols have made it easier to determine 3D structure using solid-state NMR. Dynamic nuclear polarization, a key technique to boost sensitivity of solid-state NMR at low temperatures, can help with the analysis of thermally trapped catalytic intermediates, while methods to improve signal-to-noise per time unit enable the real-time measurement of kinetics of conformational changes during the catalytic cycle.
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Affiliation(s)
- Sandra J. Ullrich
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, Max von Laue Str. 9, 60438 Frankfurt am Main, Germany
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12
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Clark NA, Swain JE. Oocyte cryopreservation: searching for novel improvement strategies. J Assist Reprod Genet 2013; 30:865-75. [PMID: 23779099 DOI: 10.1007/s10815-013-0028-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/31/2013] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To highlight emerging techniques aimed at improving oocyte cryopreservation. METHODS Review of available and relevant literature through Pubmed and Medline searches. RESULTS Oocyte cryopreservation is an increasingly common procedure utilized for assisted reproduction and may benefit several patient populations. Therefore, improving efficiency is paramount in realizing the tremendous promise of this approach. However, in addition to numerous studies looking to improve oocyte cryopreservation efficacy via examination of variables involved with protocol methodology, such as type/concentration of cryoprotectant (CPA), type of storage device, or cooling/warming rates, there are more novel approaches for improvement. These alternate approaches include utilizing different the stages of oocytes, examining alteration of basal media and buffer composition, optimizing CPA exchange protocols and device loading through use of automated technology, as well as examination/manipulation of oocyte cellular composition to improve cryotolerance. Finally, elucidating more accurate or insightful indicators of "success" is crucial for continued improvement of oocyte cryopreservation. CONCLUSION Oocyte cryopreservation has improved dramatically in recent years and is receiving widespread clinical use. Novel approaches to further improve success, as well as improved methods to assess this success will aid in continued improvement.
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Affiliation(s)
- Natalie A Clark
- Department of OB/GYN, University of Michigan, Ann Arbor, MI 48108, USA
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13
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da Silva GFZ, Shinkarev VP, Kamensky YA, Palmer G. Spectroscopic Evidence of the Role of an Axial Ligand Histidinate in the Mechanism of Adrenal Cytochrome b561. Biochemistry 2012; 51:8730-42. [DOI: 10.1021/bi301127k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giordano F. Z. da Silva
- Department
of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, United States
| | - Vladimir P. Shinkarev
- Department
of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, United States
| | - Yury A. Kamensky
- Department
of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, United States
| | - Graham Palmer
- Department
of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, United States
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14
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Cryoradiolysis and cryospectroscopy for studies of heme-oxygen intermediates in cytochromes p450. Methods Mol Biol 2012; 875:375-91. [PMID: 22573452 DOI: 10.1007/978-1-61779-806-1_20] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cryogenic radiolytic reduction is one of the most straightforward and convenient methods of generation and stabilization of reactive iron-oxygen intermediates for mechanistic studies in chemistry and biochemistry. The method is based on one-electron reduction of the precursor complex in frozen solution via exposure to the ionizing radiation at cryogenic temperatures. Such approach allows for accumulation of the fleeting reactive complexes which otherwise could not be generated at sufficient amount for structural and mechanistic studies. Application of this method allowed for characterizing of peroxo-ferric and hydroperoxo-ferric intermediates, which are common for the oxygen activation mechanism in cytochromes P450, heme oxygenases, and nitric oxide synthases, as well as for the peroxide metabolism by peroxidases and catalases.
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15
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New SY, Marshall NM, Hor TSA, Xue F, Lu Y. Redox tuning of two biological copper centers through non-covalent interactions: same trend but different magnitude. Chem Commun (Camb) 2012; 48:4217-9. [DOI: 10.1039/c2cc30901g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wilson TD, Savelieff MG, Nilges MJ, Marshall NM, Lu Y. Kinetics of Copper Incorporation into a Biosynthetic Purple CuA Azurin: Characterization of Red, Blue, and a New Intermediate Species. J Am Chem Soc 2011; 133:20778-92. [DOI: 10.1021/ja205281t] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Tiffany D. Wilson
- Department of Chemistry, University of Illinois at Urbana—Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Masha G. Savelieff
- Department of Chemistry, University of Illinois at Urbana—Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Mark J. Nilges
- Department of Chemistry, University of Illinois at Urbana—Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Nicholas M. Marshall
- Department of Chemistry, University of Illinois at Urbana—Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana—Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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Reineke K, Mathys A, Knorr D. Shift of pH-Value During Thermal Treatments in Buffer Solutions and Selected Foods. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2011. [DOI: 10.1080/10942910903456978] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Will MA, Clark NA, Swain JE. Biological pH buffers in IVF: help or hindrance to success. J Assist Reprod Genet 2011; 28:711-24. [PMID: 21614519 DOI: 10.1007/s10815-011-9582-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022] Open
Abstract
PURPOSE Minimizing environmental stress helps maintain cellular homeostasis and is a crucial component in optimizing embryo development in vitro and resulting ART success. One stressor of particular interest is pH. Biologic buffers, such as HEPES and MOPS, are valuable tools for stabilizing pH. The objective of this manuscript is to summarize efficacy and impact of various pH buffers used during IVF lab procedures METHODS Keyword searches were performed using Pubmed and Medline and relevant literature reviewed. RESULTS Various pH buffers have been used with varying degrees of success for gamete and embryo processing in a variety of animal species, as well as in human. CONCLUSION Though biologic buffers off a means to improve pH stability, not all buffers may be appropriate for use with gametes and embryos. Specific buffers may have undesired effects, and these may be buffer, species, cell type or concentration dependent. Continued research is needed to further refine and improve the use of biologic buffers for use in human ART.
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Affiliation(s)
- Matthew A Will
- Department of Obstetrics & Gynecology, University of Michigan, Ann Arbor, MI 48108, USA
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Ewing GW, Parvez SH. The multi-systemic nature of diabetes mellitus: Genotype or phenotype? NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2010; 2:444-56. [PMID: 22558546 PMCID: PMC3339106 DOI: 10.4297/najms.2010.2444] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND This article discusses factors which materially influence the diagnosis, prevention and treatment of diabetes mellitus but which may be overlooked by the prevailing biomedical paradigm. That cognition can be mathematically linked to the function of the autonomic nervous system and physiological systems casts new light upon the mechanisms responsible for homeostasis and origins of disease. In particular, it highlights the limitations of the reductionist biomedical approach which considers mainly the biochemistry of single pathologies rather than considering the neural mechanisms which regulate the function of physiological systems, and inherent visceral organs; and which are subsequently manifest as biochemistries of varying degrees of complexity and severity. As a consequence, histopathological tests are fraught with inherent limitations and many categories of drugs are significantly ineffective. AIMS Such limitations may be explained if disease (in particular diabetes mellitus) has multiple origins, is multi-systemic in nature and, depending upon the characteristics of each pathology, is influenced by genotype and/or phenotype. RESULTS This article highlights the influence of factors which are not yet considered re. the aetiology of diabetes mellitus e.g. the influence of light and sensory input upon the stability of the autonomic nervous system; the influence of raised plasma viscosity upon rates of reaction; the influence of viruses and/or of modified live viruses given in vaccinations; systemic instability, in particular the adverse influence of drinks and lack of exercise upon the body's prevailing pH and its subsequent influence upon levels of magnesium and other essential trace elements. CONCLUSIONS This application of the top-down systems biology approach may provide a plausible and inclusive explanation for the nature and occurrence of diabetes mellitus.
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Affiliation(s)
- Graham Wilfred Ewing
- Montague Healthcare, Mulberry House, 6 Vine Farm Close, Cotgrave, Nottingham NG12 3TU, United Kingdom
| | - Syed Hasan Parvez
- CNRS Neuroendocrine Unit, Institute Alfred Fessard of Neurosciences, Bât 5, Parc Chateau CNRS, 91190 Gif Sur Yvette, France
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Swain JE. Optimizing the culture environment in the IVF laboratory: impact of pH and buffer capacity on gamete and embryo quality. Reprod Biomed Online 2010; 21:6-16. [PMID: 20570214 DOI: 10.1016/j.rbmo.2010.03.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 03/09/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
Supplying and maintaining appropriate culture conditions is critical to minimize stress imposed upon gametes and embryos and to optimize the in-vitro environment. One parameter that requires close scrutiny in this endeavour is pH. Though embryos have a limited ability to regulate their internal pH (pH(i)), oocytes lack robust mechanisms. Thus, careful attention to external pH (pH(e)) of culture media is imperative in IVF. Ability to withstand deviations in hydrogen ion concentration varies depending on culture conditions, as well as laboratory procedures. Cryopreserved--thaw--thawed embryos, as well as denuded oocytes, are especially susceptible to perturbations in pH(e). Therefore, proper setting, monitoring and stabilizing of pH(e) during IVF laboratory procedures is a crucial component of a rigorous quality control programme. Here, importance of both pH(i) and pH(e) in respect to gamete and embryo quality are discussed. Furthermore, factors influencing selection of pH(e), as well as emerging methods to stabilize pH(e) in the IVF laboratory are detailed.
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Affiliation(s)
- Jason E Swain
- University of Michigan, OB GYN, Ann Arbor, MI 48108, USA.
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21
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Impact of freezing on pH of buffered solutions and consequences for monoclonal antibody aggregation. Biotechnol Prog 2009; 26:727-33. [DOI: 10.1002/btpr.377] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Ewing GW, Ewing EN. Computer diagnosis in cardiology. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2009; 1:152-9. [PMID: 22666689 PMCID: PMC3364659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This article reports upon the emergence of a novel cognitive, computer-based technology which may lead to significantly improved methods of cardiological diagnosis and a rapid and inexpensive method of cardiological screening.The technology 'Virtual Scanning' illustrates how, in blood, the reaction of proteins and their reactive substrates releases light; that the colour and intensity of this bioluminescence is unique to each reaction and it's rate; and that the development of pathologies influence cognition and visual perception. This illustrates that the function of the autonomic nervous system is linked to that of the physiological systems and that the rate of biochemical reactions, and the progression of disease, can be measured by a cognitive test procedure and used as an indication of the disease(s) affecting heart function.The article discusses the limitations of the conventional biomarker technique, and the potential value of non-invasive cognitive techniques, such as Virtual Scanning, to the medical practitioner. Finally, it discusses how the ability of Virtual Scanning to diagnose disease from its presymptomatic origins may lead to improved diagnostic accuracy and significantly reduced costs.
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Affiliation(s)
- Graham Wilfred Ewing
- Montague Healthcare, Mulberry House, Vine Farm Close, Cotgrave, Nottingham, United Kingdom,Correspondence to: Graham Wilfred Ewing, Montague Healthcare, Mulberry House, 6 Vine Farm Close, Cotgrave, Nottingham NG12 3TU, England. Tel.: 0115-9890304/9899618, Fax: 0115-9899826.
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Sarell CJ, Syme CD, Rigby SEJ, Viles JH. Copper(II) binding to amyloid-beta fibrils of Alzheimer's disease reveals a picomolar affinity: stoichiometry and coordination geometry are independent of Abeta oligomeric form. Biochemistry 2009; 48:4388-402. [PMID: 19338344 DOI: 10.1021/bi900254n] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cu(2+) ions are found concentrated within senile plaques of Alzheimer's disease patients directly bound to amyloid-beta peptide (Abeta) and are linked to the neurotoxicity and self-association of Abeta. The affinity of Cu(2+) for monomeric Abeta is highly disputed, and there have been no reports of affinity of Cu(2+) for fibrillar Abeta. We therefore measured the affinity of Cu(2+) for both monomeric and fibrillar Abeta(1-42) using two independent methods: fluorescence quenching and circular dichroism. The binding curves were almost identical for both fibrillar and monomeric forms. Competition studies with free glycine, l-histidine, and nitrilotriacetic acid (NTA) indicate an apparent (conditional) dissociation constant of 10(-11) M, at pH 7.4. Previous studies of Cu-Abeta have typically found the affinity 2 or more orders of magnitude weaker, largely because the affinity of competing ligands or buffers has been underestimated. Abeta fibers are able to bind a full stoichiometric complement of Cu(2+) ions with little change in their secondary structure and have coordination geometry identical to that of monomeric Abeta. Electron paramagnetic resonance studies (EPR) with Abeta His/Ala analogues suggest a dynamic view of the tetragonal Cu(2+) complex, with axial as well as equatorial coordination of imidazole nitrogens creating an ensemble of coordination geometries in exchange between each other. Furthermore, the N-terminal amino group is essential for the formation of high-pH complex II. The Abeta(1-28) fragment binds an additional Cu(2+) ion compared to full-length Abeta, with appreciable affinity. This second binding site is revealed in Abeta(1-42) upon addition of methanol, indicating hydrophobic interactions block the formation of this weaker carboxylate-rich complex. A Cu(2+) affinity for Abeta of 10(11) M(-1) supports a modified amyloid cascade hypothesis in which Cu(2+) is central to Abeta neurotoxicity.
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Affiliation(s)
- Claire J Sarell
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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Thermodynamic equilibrium between blue and green copper sites and the role of the protein in controlling function. Proc Natl Acad Sci U S A 2009; 106:4969-74. [PMID: 19282479 DOI: 10.1073/pnas.0900995106] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A combination of spectroscopies and density functional theory calculations indicate that there are large temperature-dependent absorption spectral changes present in green nitrite reductases (NiRs) due to a thermodynamic equilibrium between a green and a blue type 1 (T1) copper site. The axial methionine (Met) ligand is unconstrained in the oxidized NiRs, which results in an enthalpically favored (DeltaH approximately 4.6 kcal/mol) Met-bound green copper site at low temperatures, and an entropically favored (TDeltaS approximately 4.5 kcal/mol, at room temperature) Met-elongated blue copper site at elevated temperatures. In contrast to the NiRs, the classic blue copper sites in plastocyanin and azurin show no temperature-dependent behavior, indicating that a single species is present at all temperatures. For these blue copper proteins, the polypeptide matrix opposes the gain in entropy that would be associated with the loss of the weak axial Met ligand at physiological temperatures by constraining its coordination to copper. The potential energy surfaces of Met binding indicate that it stabilizes the oxidized state more than the reduced state. This provides a mechanism to tune down the reduction potential of blue copper sites by >200 mV.
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Lipton AS, Heck RW, Hernick M, Fierke CA, Ellis PD. Residue ionization in LpxC directly observed by 67Zn NMR spectroscopy. J Am Chem Soc 2008; 130:12671-9. [PMID: 18761443 DOI: 10.1021/ja801776c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The pH dependence of the solid-state (67)Zn NMR lineshapes has been measured for both the wild type (WT) and the H265A mutant of Aquifex aeolicus LpxC, each in the absence of substrate (resting state). The (67)Zn NMR spectrum of WT LpxC at pH 6 (prepared at 0 degrees C) contains two overlapping quadrupole lineshapes with C q values of 10 and 12.9 MHz, while the spectrum measured for the sample prepared at a pH near 9 (at 0 degrees C) is dominated by the appearance of a third species with a C q of 14.3 MHz. These findings are consistent with the two p K a values previously observed by the bell-shaped dependence of the LpxC-catalyzed reaction. On the basis of comparison of the experimental results with predictions from quantum mechanical/molecular mechanical (QM/MM) modeling, we suggest that p K a1 (low pH) represents the ionization of Glu78 and p K a2 (high pH) reflects the ionization of another active site residue located near the zinc ion, such as His265. These results are also consistent with water being bound to the Zn (2+) ion throughout this pH range. The (67)Zn NMR spectra of the H265A mutant appear to be pH independent, with a C q of 9.55 MHz being sufficient to describe both low- and high-pH data. The QM/MM models of the H265A mutant suggest that over this pH range water is bound to the zinc ion while Glu78 is protonated.
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Affiliation(s)
- Andrew S Lipton
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352, USA
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