1
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Chan KK, Sundaram V, Tan J, Ho YK, Ramanan RN, Ooi CW. Enhanced activity of Candida antarctica lipase B in cholinium aminoate ionic liquids: a combined experimental and computational analysis. J Biomol Struct Dyn 2023:1-15. [PMID: 37787564 DOI: 10.1080/07391102.2023.2262590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/16/2023] [Indexed: 10/04/2023]
Abstract
As a class of ionic liquids with higher biocompatibility, cholinium aminoates ([Cho][AA]) hold potential as solvation media for enzymatic bioprocessing. Herein, solvation effect of [Cho][AA] on structural stability and enzymatic activity of Candida antarctica lipase B (CALB) was evaluated using experimental and computational approaches. Influence of [Cho][AA] on CALB stability was investigated using amino acid anions ([AA]-) with varying hydrophobicity levels. Choline phenylalaninate ([Cho][Phe]) resulted in 109.1% and 110.4% of relative CALB activity to buffer medium at 25 °C and 50 °C, respectively. Simulation results revealed the improvement of CALB's enzymatic activities by [AA]- with a strong hydrophobic character. Shielding of CALB from water molecules by [AA]- was observed. The level of CALB activity was governed by accumulation level of [AA]- at CALB's first hydration layer. The stronger interaction between His224 and Asp187 was postulated to be driven by [Cho][AA], resulting in the activity enhancement of CALB. The slight improvement of CALB activity in 0.05 M [Cho][Phe] at 50 °C could be due to the larger size of entrance to the catalytic site and the stronger interaction between the catalytic residues. The promising effect of [Cho][Phe] on CALB activation may stimulate research efforts in designing a 'fully green' bioreaction for various industrial applications.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kam Khong Chan
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Vidya Sundaram
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
- Biological Engineering Discipline, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Jully Tan
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Yong Kuen Ho
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Ramakrishnan Nagasundara Ramanan
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
| | - Chien Wei Ooi
- Chemical Engineering Department, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
- Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor, Malaysia
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2
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Wang Y, Zhang JY, Teng JY, Xiong HF, Li QF. Biochemical characteristics of point mutated Capra hircus lysosome α-mannosidase. J Vet Med Sci 2023; 85:244-251. [PMID: 36596563 PMCID: PMC10017285 DOI: 10.1292/jvms.22-0222] [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: 01/02/2023] Open
Abstract
Locoweeds, a type of poisonous weedare, are widely distributed throughout the world and have a significant impact on the development of herbivore animal husbandry. Swainsonine (SW), the main toxin in locoweeds, can competitively inhibit lysosomes α-mannosidase (LAM) in animal cells, resulting in α-mannosidosis. However, the specifics of the interaction between SW and LAM are still unclear. Here, we used molecular docking to predicte the interaction points between SW and LAM, built mutated lysosomes α-mannosidase (LAMM), and analyzed its biochemical properties changes in presumption points. The Trp at the 28th position and the Tyr at the 599th position of the LAM were interaction point candidates, and the above two amino acids in Capra hircus LAM (chLAM), were successfully mutated to glycine by constructing recombinant yeast GS115/PIC9K- LAMM. The results showed that the sensitivity of Capra hircus LAMM (chLAMM), to SW decreased significantly compared with wild-type LAM, the enzyme activity of LAM decreased approximately threefold, the optimum temperature of LAMM decreased from 55°C to 50°C, the optimum pH value increased from 4.5 to 5.0, and the effects of Mn2+, Fe3+, Al3+, Co2+, Cr3+, and ethylenediaminetetraacetic acid (EDTA) on LAM enzyme activity before and after point mutation changed significantly. These findings help us better understanding the molecular mechanism of the interaction mechanism between SW and chLAM, and provide new reference for solving locoweeds poisoning.
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Affiliation(s)
- Yan Wang
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jiang-Ye Zhang
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jun-Yang Teng
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Hao-Fei Xiong
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Qin-Fan Li
- Department of Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
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3
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China H, Ogino H. Effect of attaching hydrophilic oligopeptides to the C-terminus of organic solvent-tolerant metal-free bromoperoxidase BPO-A1 from Streptomyces aureofaciens on organic solvent-stability. Biochem Biophys Res Commun 2023; 640:142-149. [PMID: 36508927 DOI: 10.1016/j.bbrc.2022.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022]
Abstract
Metal-free bromoperoxidase BPO-A1 from Streptomyces aureofacience was selected among several similar enzymes exhibiting brominating activity as the most stable haloperoxidase against 70%(v/v) methanol. A comparison of the BPO-A1 and octahistidine-tagged BPO-A1 at the C-terminus (BPO-A1-His8) revealed that the His-tag enhanced the organic solvent-stability of BPO-A1 with pH- and heat-stabilities. Additionally, the contribution of the hydrophilicity at the C-terminal of BPO-A1 to the organic solvent-stability was confirmed employing several mutants bearing hydrophilic oligopeptides. Fortunately, two excellent mutants, BPO-A1-Lys8 and BPO-A1-Arg8, with high stabilities against various water-miscible organic solvents were obtained. In conclusion, the enhancing effect of the hydrophilic oligopeptides on the organic solvent-stability was associated with a decrease in the hydrophobic surface area near the C-terminus.
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Affiliation(s)
- Hideyasu China
- Department of Medical Bioscience, Nagahama Institute of Bio-Science and Technology, 1266, Tamuracho Nagahama-shi, Shiga, 526-0829, Japan.
| | - Hiroyasu Ogino
- Department of Chemical Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka, 599-8531, Japan.
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4
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Heat-induced unfolding facilitates plant protein digestibility during in vitro static infant digestion. Food Chem 2021; 375:131878. [PMID: 34952386 DOI: 10.1016/j.foodchem.2021.131878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 11/22/2022]
Abstract
Soy protein is the main protein source for plant-based infant formula, whereas pea protein is considered as a potential alternative plant protein source. This study assessed the structural changes of soy and pea proteins after heating between 65 °C and 100 °C, and its effects on the in vitro digestibility in the context of infant digestion. We found that with increased heating intensity, both soy and pea proteins unfolded, manifested as the increased surface hydrophobicity, thereby potentially improving the accessibility to digestive enzymes. Their final in vitro digestibility increased from ∼ 30% of non-treated samples to ∼ 60% of 100 °C-heated samples for soy protein, and from ∼ 52% to ∼ 65% for pea protein. Surface hydrophobicity was strongly positively correlated to the overall digestibility. Therefore, the heating temperatures that enabled protein unfolding promoted the digestibility of soy and pea proteins under infant digestion conditions.
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5
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Zhao VY, Rodrigues JV, Lozovsky ER, Hartl DL, Shakhnovich EI. Switching an active site helix in dihydrofolate reductase reveals limits to subdomain modularity. Biophys J 2021; 120:4738-4750. [PMID: 34571014 PMCID: PMC8595743 DOI: 10.1016/j.bpj.2021.09.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 11/23/2022] Open
Abstract
To what degree are individual structural elements within proteins modular such that similar structures from unrelated proteins can be interchanged? We study subdomain modularity by creating 20 chimeras of an enzyme, Escherichia coli dihydrofolate reductase (DHFR), in which a catalytically important, 10-residue α-helical sequence is replaced by α-helical sequences from a diverse set of proteins. The chimeras stably fold but have a range of diminished thermal stabilities and catalytic activities. Evolutionary coupling analysis indicates that the residues of this α-helix are under selection pressure to maintain catalytic activity in DHFR. Reversion to phenylalanine at key position 31 was found to partially restore catalytic activity, which could be explained by evolutionary coupling values. We performed molecular dynamics simulations using replica exchange with solute tempering. Chimeras with low catalytic activity exhibit nonhelical conformations that block the binding site and disrupt the positioning of the catalytically essential residue D27. Simulation observables and in vitro measurements of thermal stability and substrate-binding affinity are strongly correlated. Several E. coli strains with chromosomally integrated chimeric DHFRs can grow, with growth rates that follow predictions from a kinetic flux model that depends on the intracellular abundance and catalytic activity of DHFR. Our findings show that although α-helices are not universally substitutable, the molecular and fitness effects of modular segments can be predicted by the biophysical compatibility of the replacement segment.
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Affiliation(s)
- Victor Y Zhao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - João V Rodrigues
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Elena R Lozovsky
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts.
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Starr TN, Greaney AJ, Hilton SK, Ellis D, Crawford KHD, Dingens AS, Navarro MJ, Bowen JE, Tortorici MA, Walls AC, King NP, Veesler D, Bloom JD. Deep Mutational Scanning of SARS-CoV-2 Receptor Binding Domain Reveals Constraints on Folding and ACE2 Binding. Cell 2020; 182:1295-1310.e20. [PMID: 32841599 PMCID: PMC7418704 DOI: 10.1016/j.cell.2020.08.012] [Citation(s) in RCA: 1372] [Impact Index Per Article: 343.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 02/07/2023]
Abstract
The receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein mediates viral attachment to ACE2 receptor and is a major determinant of host range and a dominant target of neutralizing antibodies. Here, we experimentally measure how all amino acid mutations to the RBD affect expression of folded protein and its affinity for ACE2. Most mutations are deleterious for RBD expression and ACE2 binding, and we identify constrained regions on the RBD's surface that may be desirable targets for vaccines and antibody-based therapeutics. But a substantial number of mutations are well tolerated or even enhance ACE2 binding, including at ACE2 interface residues that vary across SARS-related coronaviruses. However, we find no evidence that these ACE2-affinity-enhancing mutations have been selected in current SARS-CoV-2 pandemic isolates. We present an interactive visualization and open analysis pipeline to facilitate use of our dataset for vaccine design and functional annotation of mutations observed during viral surveillance.
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Affiliation(s)
- Tyler N Starr
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Allison J Greaney
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Medical Scientist Training Program, University of Washington, Seattle, WA 98195, USA
| | - Sarah K Hilton
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Daniel Ellis
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195, USA
| | - Katharine H D Crawford
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Medical Scientist Training Program, University of Washington, Seattle, WA 98195, USA
| | - Adam S Dingens
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Mary Jane Navarro
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - John E Bowen
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Alexandra C Walls
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Neil P King
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jesse D Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, Seattle, WA 98109, USA.
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7
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Starr TN, Greaney AJ, Hilton SK, Crawford KH, Navarro MJ, Bowen JE, Tortorici MA, Walls AC, Veesler D, Bloom JD. Deep mutational scanning of SARS-CoV-2 receptor binding domain reveals constraints on folding and ACE2 binding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.06.17.157982. [PMID: 32587970 PMCID: PMC7310626 DOI: 10.1101/2020.06.17.157982] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein mediates viral attachment to ACE2 receptor, and is a major determinant of host range and a dominant target of neutralizing antibodies. Here we experimentally measure how all amino-acid mutations to the RBD affect expression of folded protein and its affinity for ACE2. Most mutations are deleterious for RBD expression and ACE2 binding, and we identify constrained regions on the RBD's surface that may be desirable targets for vaccines and antibody-based therapeutics. But a substantial number of mutations are well tolerated or even enhance ACE2 binding, including at ACE2 interface residues that vary across SARS-related coronaviruses. However, we find no evidence that these ACE2-affinity enhancing mutations have been selected in current SARS-CoV-2 pandemic isolates. We present an interactive visualization and open analysis pipeline to facilitate use of our dataset for vaccine design and functional annotation of mutations observed during viral surveillance.
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Affiliation(s)
- Tyler N. Starr
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Co-first authors
| | - Allison J. Greaney
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA 98195, USA
- Co-first authors
| | - Sarah K. Hilton
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Katharine H.D. Crawford
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA 98195, USA
| | - Mary Jane Navarro
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - John E. Bowen
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Alexandra C. Walls
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jesse D. Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, Seattle, WA 98109, USA
- Lead Contact
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8
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Abstract
A Monte Carlo simulation based sequence design method is proposed to explore the effect of correlated pair mutations in proteins. In the designed sequences, the most correlated residue pairs are identified and mutated with all possible amino acid pairs except those already present. The cumulative correlated pair mutations generated an array of mutated sequences. Results show a significant increase in the probability of misfolding for correlated pair mutations as compared to that of the random pair mutations. The pair mutations of correlated residues that are in contact record a higher probability of misfolding as compared to the correlated residues that are not in contact. The probability of misfolding increases on pair mutation of nonlocally correlated residue pairs as compared to that of the locally correlated residue pairs. The choice of a compact or expanded conformation does not depend on the type of correlated pair mutations. Pair mutation of the most correlated residue pairs at the surface with hydrophobic amino acids results in higher misfolding probability as compared to that in the core. An exactly opposite behavior is observed on pair mutation with hydrophilic and charged amino acid pairs. The neutral amino acid pairs do not differentiate between core and surface sites. This study may be used for targeted mutation experiments to predict complex mutation patterns, reengineer the existing proteins, and design new proteins with reduced misfolding propensity.
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Affiliation(s)
- Adesh Kumar
- Department of Chemistry , University of Delhi , Delhi 110007 , India
| | - Parbati Biswas
- Department of Chemistry , University of Delhi , Delhi 110007 , India
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9
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Islam MM, Kobayashi K, Kidokoro S, Kuroda Y. Hydrophobic surface residues can stabilize a protein through improved water–protein interactions. FEBS J 2019; 286:4122-4134. [DOI: 10.1111/febs.14941] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/19/2019] [Accepted: 05/28/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Mohammad M. Islam
- Department of Biochemistry and Molecular Biology University of Chittagong Chittagong Bangladesh
- Department of Biotechnology and Life Science Tokyo University of Agriculture and Technology Tokyo Japan
| | - Kei Kobayashi
- Department of Biotechnology and Life Science Tokyo University of Agriculture and Technology Tokyo Japan
| | - Shun‐Ichi Kidokoro
- Department of Bioengineering Nagaoka University of Technology Niigata Japan
| | - Yutaka Kuroda
- Department of Biotechnology and Life Science Tokyo University of Agriculture and Technology Tokyo Japan
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10
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Kumar A, Biswas P. Effect of site-directed point mutations on protein misfolding: A simulation study. Proteins 2019; 87:760-773. [PMID: 31017329 DOI: 10.1002/prot.25702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 03/19/2019] [Accepted: 04/22/2019] [Indexed: 11/09/2022]
Abstract
A Monte Carlo simulation based sequence design method is proposed to investigate the role of site-directed point mutations in protein misfolding. Site-directed point mutations are incorporated in the designed sequences of selected proteins. While most mutated sequences correctly fold to their native conformation, some of them stabilize in other nonnative conformations and thus misfold/unfold. The results suggest that a critical number of hydrophobic amino acid residues must be present in the core of the correctly folded proteins, whereas proteins misfold/unfold if this number of hydrophobic residues falls below the critical limit. A protein can accommodate only a particular number of hydrophobic residues at the surface, provided a large number of hydrophilic residues are present at the surface and critical hydrophobicity of the core is preserved. Some surface sites are observed to be equally sensitive toward site-directed point mutations as the core sites. Point mutations with highly polar and charged amino acids increases the misfold/unfold propensity of proteins. Substitution of natural amino acids at sites with different number of nonbonded contacts suggests that both amino acid identity and its respective site-specificity determine the stability of a protein. A clash-match method is developed to calculate the number of matching and clashing interactions in the mutated protein sequences. While misfolded/unfolded sequences have a higher number of clashing and a lower number of matching interactions, the correctly folded sequences have a lower number of clashing and a higher number of matching interactions. These results are valid for different SCOP classes of proteins.
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Affiliation(s)
- Adesh Kumar
- Department of Chemistry, University of Delhi, Delhi, India
| | - Parbati Biswas
- Department of Chemistry, University of Delhi, Delhi, India
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11
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Whittington AC, Rokyta DR. Biophysical Spandrels form a Hot-Spot for Kosmotropic Mutations in Bacteriophage Thermal Adaptation. J Mol Evol 2018; 87:27-36. [PMID: 30564861 DOI: 10.1007/s00239-018-9882-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/15/2018] [Indexed: 12/18/2022]
Abstract
Temperature plays a dominating role in protein structure and function, and life has evolved myriad strategies to adapt proteins to environmental thermal stress. Cellular systems can utilize kosmotropic osmolytes, the products of complex biochemical pathways, to act as chemical chaperones. These extrinsic molecules, e.g., trehalose, alter local water structure to modulate the strength of the hydrophobic effect and increase protein stability. In contrast, simpler genetic systems must rely on intrinsic mutation to affect protein stability. In naturally occurring microvirid bacteriophages of the subfamily Bullavirinae, capsid stability is randomly distributed across the phylogeny, suggesting it is not phylogenetically linked and could be altered through adaptive mutation. We hypothesized that these phages could utilize an adaptive mechanism that mimics the stabilizing effects of the kosmotrope trehalose through mutation. Kinetic stability of wild-type ID8, a relative of ΦX174, displays a saturable response to trehalose. Thermal adaptation mutations in ID8 improve capsid stability and reduce responsiveness to trehalose suggesting the mutations move stability closer to the kosmotropic saturation point, mimicking the kosmotropic effect of trehalose. These mutations localize to and modulate the hydrophobicity of a cavern formation at the interface of phage coat and spike proteins-an evolutionary spandrel. Across a series of genetically distinct phages, responsiveness to trehalose correlates positively with cavern hydrophobicity suggesting that the level of hydrophobicity of the cavern may provide a biophysical gating mechanism constraining or permitting adaptation in a lineage-specific manner. Our results demonstrate that a single mutation can exploit pre-existing, non-adaptive structural features to mimic the adaptive effects of complex biochemical pathways.
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Affiliation(s)
- A Carl Whittington
- Department of Biological Science, Florida State University, 319 Stadium Dr., Tallahassee, FL, 32306, USA.
| | - Darin R Rokyta
- Department of Biological Science, Florida State University, 319 Stadium Dr., Tallahassee, FL, 32306, USA
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12
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Xu Z, Cai T, Xiong N, Zou SP, Xue YP, Zheng YG. Engineering the residues on “A” surface and C-terminal region to improve thermostability of nitrilase. Enzyme Microb Technol 2018; 113:52-58. [DOI: 10.1016/j.enzmictec.2018.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/28/2018] [Accepted: 03/04/2018] [Indexed: 12/29/2022]
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13
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Michael E, Polydorides S, Simonson T, Archontis G. Simple models for nonpolar solvation: Parameterization and testing. J Comput Chem 2017; 38:2509-2519. [PMID: 28786118 DOI: 10.1002/jcc.24910] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 12/13/2022]
Abstract
Implicit solvent models are important for many biomolecular simulations. The polarity of aqueous solvent is essential and qualitatively captured by continuum electrostatics methods like Generalized Born (GB). However, GB does not account for the solvent-induced interactions between exposed hydrophobic sidechains or solute-solvent dispersion interactions. These "nonpolar" effects are often modeled through surface area (SA) energy terms, which lack realism, create mathematical singularities, and have a many-body character. We have explored an alternate, Lazaridis-Karplus (LK) gaussian energy density for nonpolar effects and a dispersion (DI) energy term proposed earlier, associated with GB electrostatics. We parameterized several combinations of GB, SA, LK, and DI energy terms, to reproduce 62 small molecule solvation free energies, 387 protein stability changes due to point mutations, and the structures of 8 protein loops. With optimized parameters, the models all gave similar results, with GBLK and GBDILK giving no performance loss compared to GBSA, and mean errors of 1.7 kcal/mol for the stability changes and 2 Å deviations for the loop conformations. The optimized GBLK model gave poor results in MD of the Trpcage mini-protein, but parameters optimized specifically for MD performed well for Trpcage and three other small proteins. Overall, the LK and DI nonpolar terms are valid alternatives to SA treatments for a range of applications. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Eleni Michael
- Department of Physics, University of Cyprus, PO20537, Nicosia, CY1678, Cyprus
| | - Savvas Polydorides
- Department of Physics, University of Cyprus, PO20537, Nicosia, CY1678, Cyprus.,Laboratoire de Biochimie (CNRS UMR7654), Ecole Polytechnique, Palaiseau, France
| | - Thomas Simonson
- Laboratoire de Biochimie (CNRS UMR7654), Ecole Polytechnique, Palaiseau, France
| | - Georgios Archontis
- Department of Physics, University of Cyprus, PO20537, Nicosia, CY1678, Cyprus
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14
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Diao H, Zhang C, Wang S, Lu F, Lu Z. Enhanced Thermostability of Lipoxygenase from Anabaena sp. PCC 7120 by Site-Directed Mutagenesis Based on Computer-Aided Rational Design. Appl Biochem Biotechnol 2015; 178:1339-50. [DOI: 10.1007/s12010-015-1950-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 12/07/2015] [Indexed: 01/23/2023]
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15
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Reddy B, Kelawala DN, Shah T, Patel AB, Patil DB, Parikh PV, Patel N, Parmar N, Mohapatra AB, Singh KM, Menon R, Pandya D, Jakhesara SJ, Koringa PG, Rao MV, Joshi CG. Identification of putative SNPs in progressive retinal atrophy affected Canis lupus familiaris using exome sequencing. Mamm Genome 2015; 26:638-49. [PMID: 26515695 DOI: 10.1007/s00335-015-9607-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/08/2015] [Indexed: 11/30/2022]
Abstract
Progressive retinal atrophy (PRA) is one of the major causes of retinal photoreceptor cell degeneration in canines. The inheritance pattern of PRA is autosomal recessive and genetically heterogeneous. Here, using targeted sequencing technology, we have performed exome sequencing of 10 PRA-affected (Spitz=7, Cocker Spaniel=1, Lhasa Aphso=1 and Spitz-Labrador cross breed=1) and 6 normal (Spitz=5, Cocker Spaniel=1) dogs. The high-throughput sequencing using 454-Roche Titanium sequencer generated about 2.16 Giga bases of raw data. Initially, we have successfully identified 25,619 single nucleotide polymorphisms (SNPs) that passed the stringent SNP calling parameters. Further, we performed association study on the cohort, and the highly significant (0.001) associations were short-listed and investigated in-depth. Out of the 171 significant SNPs, 113 were previously unreported. Interestingly, six among them were non-synonymous coding (NSC) SNPs, which includes CPPED1 A>G (p.M307V), PITRM1 T>G (p.S715A), APP G>A (p.T266M), RNF213 A>G (p.V1482A), C>A (p.V1456L), and SLC46A3 G>A (p.R168Q). On the other hand, 35 out of 113 unreported SNPs were falling in regulatory regions such as 3'-UTR, 5'-UTR, etc. In-depth bioinformatics analysis revealed that majority of NSC SNPs have damaging effect and alter protein stability. This study highlighted the genetic markers associated with PRA, which will help to develop genetic assay-based screening in effective breeding.
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Affiliation(s)
- Bhaskar Reddy
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India.,Department of Zoology, Genetic Diagnostic Centre, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Divyesh N Kelawala
- Department of Veterinary Surgery & Radiology, College of Veterinary Science & Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Tejas Shah
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Anand B Patel
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Deepak B Patil
- Department of Veterinary Surgery & Radiology, College of Veterinary Science & Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Pinesh V Parikh
- Department of Veterinary Surgery & Radiology, College of Veterinary Science & Animal Husbandry, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Namrata Patel
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Nidhi Parmar
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Amit B Mohapatra
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Krishna M Singh
- Datar Genetics Ltd, F-8, D Road, Ambad, Nasik, Maharashtra, 422010, India
| | - Ramesh Menon
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Dipal Pandya
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Subhash J Jakhesara
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Prakash G Koringa
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India
| | - Mandava V Rao
- Department of Zoology, Genetic Diagnostic Centre, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Chaitanya G Joshi
- Ome Research Facility, Department of Animal Biotechnology, Anand Agricultural University, Anand, Gujarat, 388001, India.
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Shen W, Liang XH, Sun H, Crooke ST. 2'-Fluoro-modified phosphorothioate oligonucleotide can cause rapid degradation of P54nrb and PSF. Nucleic Acids Res 2015; 43:4569-78. [PMID: 25855809 PMCID: PMC4482069 DOI: 10.1093/nar/gkv298] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 03/26/2015] [Indexed: 12/14/2022] Open
Abstract
Synthetic oligonucleotides are used to regulate gene expression through different mechanisms. Chemical modifications of the backbone of the nucleic acid and/or of the 2′ moiety of the ribose can increase nuclease stability and/or binding affinity of oligonucleotides to target molecules. Here we report that transfection of 2′-F-modified phosphorothioate oligonucleotides into cells can reduce the levels of P54nrb and PSF proteins through proteasome-mediated degradation. Such deleterious effects of 2′-F-modified oligonucleotides were observed in different cell types from different species, and were independent of oligonucleotide sequence, positions of the 2′-F-modified nucleotides in the oligonucleotides, method of delivery or mechanism of action of the oligonucleotides. Four 2′-F-modified nucleotides were sufficient to cause the protein reduction. P54nrb and PSF belong to Drosophila behavior/human splicing (DBHS) family. The third member of the family, PSPC1, was also reduced by the 2′-F-modified oligonucleotides. Preferential association of 2′-F-modified oligonucleotides with P54nrb was observed, which is partially responsible for the protein reduction. Consistent with the role of DBHS proteins in double-strand DNA break (DSB) repair, elevated DSBs were observed in cells treated with 2′-F-modified oligonucleotides, which contributed to severe impairment in cell proliferation. These results suggest that oligonucleotides with 2′-F modifications can cause non-specific loss of cellular protein(s).
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Affiliation(s)
- Wen Shen
- Department of Core Antisense Research, ISIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Xue-Hai Liang
- Department of Core Antisense Research, ISIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Hong Sun
- Department of Core Antisense Research, ISIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Stanley T Crooke
- Department of Core Antisense Research, ISIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
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17
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Baruah A, Biswas P. The role of site-directed point mutations in protein misfolding. Phys Chem Chem Phys 2014; 16:13964-73. [PMID: 24898496 DOI: 10.1039/c3cp55367a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mutations inducing higher clashing and lower matching residue pairs lead to misfolding.
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Affiliation(s)
- Anupaul Baruah
- Department of Chemistry
- University of Delhi
- Delhi-110007, India
| | - Parbati Biswas
- Department of Chemistry
- University of Delhi
- Delhi-110007, India
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18
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Simone PD, Struble LR, Kellezi A, Brown CA, Grabow CE, Khutsishvili I, Marky LA, Pavlov YI, Borgstahl GE. The human ITPA polymorphic variant P32T is destabilized by the unpacking of the hydrophobic core. J Struct Biol 2013; 182:197-208. [PMID: 23528839 PMCID: PMC4212276 DOI: 10.1016/j.jsb.2013.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 03/11/2013] [Accepted: 03/13/2013] [Indexed: 01/24/2023]
Abstract
Inosine triphosphate pyrophosphatase (ITPA), a key enzyme involved in maintaining the purity of cellular nucleoside triphosphate pools, specifically recognizes inosine triphosphate and xanthosine triphosphate (including the deoxyribose forms) and detoxifies them by catalyzing the hydrolysis of a phosphoanhydride bond, releasing pyrophosphate. This prevents their inappropriate use as substrates in enzymatic reactions utilizing (d)ATP or (d)GTP. A human genetic polymorphism leads to the substitution of Thr for Pro32 (P32T) and causes ITPA deficiency in erythrocytes, with heterozygotes having on average 22.5% residual activity, and homozygotes having undetectable activity. This polymorphism has been implicated in modulating patients' response to mercaptopurines and ribavirin. Human fibroblasts containing this variant have elevated genomic instability upon treatment with base analogs. We find that the wild-type and P32T forms are dimeric in solution and in the crystal structure. This abolishes the previous speculation that the P32T change disrupts dimerization as a mechanism of inactivation. The only difference in structure from the wild-type protein is that the area surrounding Thr32 is disrupted. Phe31 is flipped from the hydrophobic core out into the solvent, leaving a hole in the hydrophobic core of the protein which likely accounts for the reduced thermal stability of P32T ITPA and ultimately leads to its susceptibility to degradation in human cells. Circular dichroism and thermal denaturation studies confirm these structural results. We propose that the dimer of P32T variant subunit with wild-type subunit is degraded in cells similarly to the P32T homodimer explaining the level of loss of ITPA activity in heterozygotes.
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Affiliation(s)
- Peter D. Simone
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
| | - Lucas R. Struble
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Admir Kellezi
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
| | - Carrie A. Brown
- Department of Chemistry, Wayne State College, Wayne, NE 68787, USA
| | - Corinn E. Grabow
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
| | - Irine Khutsishvili
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Luis A. Marky
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Youri I. Pavlov
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Genetics, St-Petersburg University, St-Petersburg 199034, Russia
| | - Gloria E.O. Borgstahl
- The Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 987696 Nebraska Medical Center, Omaha, NE 68198-7696, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
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19
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Yu B, Zhang Y. A simple method for predicting transmembrane proteins based on wavelet transform. Int J Biol Sci 2012; 9:22-33. [PMID: 23289014 PMCID: PMC3535531 DOI: 10.7150/ijbs.5371] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/02/2012] [Indexed: 11/05/2022] Open
Abstract
The increasing protein sequences from the genome project require theoretical methods to predict transmembrane helical segments (TMHs). So far, several prediction methods have been reported, but there are some deficiencies in prediction accuracy and adaptability in these methods. In this paper, a method based on discrete wavelet transform (DWT) has been developed to predict the number and location of TMHs in membrane proteins. PDB coded as 1KQG is chosen as an example to describe the prediction process by this method. 80 proteins with known 3D structure from Mptopo database are chosen at random as data sets (including 325 TMHs) and 80 sequences are divided into 13 groups according to their function and type. TMHs prediction is carried out for each group of membrane protein sequences and obtain satisfactory result. To verify the feasibility of this method, 80 membrane protein sequences are treated as test sets, 308 TMHs can be predicted and the prediction accuracy is 96.3%. Compared with the main prediction results of seven popular prediction methods, the obtained results indicate that the proposed method in this paper has higher prediction accuracy.
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Affiliation(s)
- Bin Yu
- College of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao, Shandong, China.
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20
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Eijsink VGH, Vriend G, Van Den Burg B. Engineering a Hyperstable Enzyme by Manipulation of Early Steps in the Unfolding Process. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.3109/10242420108992029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Mora P, Carbajo RJ, Pineda-Lucena A, Sánchez del Pino MM, Pérez-Payá E. Solvent-exposed residues located in the β-sheet modulate the stability of the tetramerization domain of p53-A structural and combinatorial approach. Proteins 2007; 71:1670-85. [DOI: 10.1002/prot.21854] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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Pál G, Kouadio JLK, Artis DR, Kossiakoff AA, Sidhu SS. Comprehensive and quantitative mapping of energy landscapes for protein-protein interactions by rapid combinatorial scanning. J Biol Chem 2006; 281:22378-22385. [PMID: 16762925 DOI: 10.1074/jbc.m603826200] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel, quantitative saturation (QS) scanning strategy was developed to obtain a comprehensive data base of the structural and functional effects of all possible mutations across a large protein-protein interface. The QS scan approach was applied to the high affinity site of human growth hormone (hGH) for binding to its receptor (hGHR). Although the published structure-function data base describing this system is probably the most extensive for any large protein-protein interface, it is nonetheless too sparse to accurately describe the nature of the energetics governing the interaction. Our comprehensive data base affords a complete view of the binding site and provides important new insights into the general principles underlying protein-protein interactions. The hGH binding interface is highly adaptable to mutations, but the nature of the tolerated mutations challenges generally accepted views about the evolutionary and biophysical pressures governing protein-protein interactions. Many substitutions that would be considered chemically conservative are not tolerated, while conversely, many non-conservative substitutions can be accommodated. Furthermore, conservation across species is a poor predictor of the chemical character of tolerated substitutions across the interface. Numerous deviations from generally accepted expectations indicate that mutational tolerance is highly context dependent and, furthermore, cannot be predicted by our current knowledge base. The type of data produced by the comprehensive QS scan can fill the gaps in the structure-function matrix. The compilation of analogous data bases from studies of other protein-protein interactions should greatly aid the development of computational methods for explaining and designing molecular recognition.
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Affiliation(s)
- Gábor Pál
- Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, Cummings Life Sciences Center, University of Chicago, Chicago, Illinois 60637
| | - Jean-Louis K Kouadio
- Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, Cummings Life Sciences Center, University of Chicago, Chicago, Illinois 60637
| | - Dean R Artis
- Department of Protein Engineering, Genentech Inc., South San Francisco, California 94080
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, Cummings Life Sciences Center, University of Chicago, Chicago, Illinois 60637.
| | - Sachdev S Sidhu
- Department of Protein Engineering, Genentech Inc., South San Francisco, California 94080.
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23
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Yue P, Li Z, Moult J. Loss of protein structure stability as a major causative factor in monogenic disease. J Mol Biol 2005; 353:459-73. [PMID: 16169011 DOI: 10.1016/j.jmb.2005.08.020] [Citation(s) in RCA: 366] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2005] [Revised: 08/08/2005] [Accepted: 08/10/2005] [Indexed: 12/18/2022]
Abstract
The most common cause of monogenic disease is a single base DNA variant resulting in an amino acid substitution. In a previous study, we observed that a high fraction of these substitutions appear to result in reduction of stability of the corresponding protein structure. We have now investigated this phenomenon more fully. A set of structural effects, such as reduction in hydrophobic area, overpacking, backbone strain, and loss of electrostatic interactions, is used to represent the impact of single residue mutations on protein stability. A support vector machine (SVM) was trained on a set of mutations causative of disease, and a control set of non-disease causing mutations. In jack-knifed testing, the method identifies 74% of disease mutations, with a false positive rate of 15%. Evaluation of a set of in vitro mutagenesis data with the SVM established that the majority of disease mutations affect protein stability by 1 to 3 kcal/mol. The method's effective distinction between disease and non-disease variants, strongly supports the hypothesis that loss of protein stability is a major factor contributing to monogenic disease.
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Affiliation(s)
- Peng Yue
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA
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24
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Bhuvanakantham R, Ng ML. Analysis of self-association of West Nile virus capsid protein and the crucial role played by Trp 69 in homodimerization. Biochem Biophys Res Commun 2005; 329:246-55. [PMID: 15721300 DOI: 10.1016/j.bbrc.2005.01.121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Indexed: 12/13/2022]
Abstract
The understanding of capsid (C) protein interactions with itself would provide important data on how the core is organized in flaviviruses during assembly. In this study, West Nile (WN) virus C protein was shown to form homodimers using yeast two-hybrid analysis in conjunction with mammalian two-hybrid and in vivo co-immunoprecipitation assays. To delineate the region on the C protein which mediates C-C dimerization, truncation studies were carried out. The results obtained clearly showed that the internal hydrophobic segment flanked by helix I and helix III of WN virus C protein is essential for the self-association of C protein. The crucial role played by Trp 69 in stabilizing the self-association of C protein was also demonstrated by mutating Trp to Gly/Arg/Phe. Substitution of the Trp residue with Gly/Arg abolished the dimerization, whereas substitution with Phe decreased the self-association significantly. The results of this study pinpoint a critical residue in the C protein that potentially plays a role in stabilizing the homotypic interaction.
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Affiliation(s)
- Raghavan Bhuvanakantham
- Flavivirology Laboratory, Department of Microbiology, 5 Science Drive 2, National University of Singapore, Singapore 117597, Singapore
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25
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Middaugh CR, Edwards KL. Recent advances in our understanding of protein conformational stability from a pharmaceutical perspective. Expert Opin Investig Drugs 2005; 7:1493-500. [PMID: 15992046 DOI: 10.1517/13543784.7.9.1493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The marginal conformational stability of proteins has made them in some cases less than ideal candidates for pharmaceutical agents. Recent progress in our understanding of protein structure and stability has provided the opportunity to design the desired degree of stability into protein drug candidates. Modifications such as the optimisation of interior side-chain packing, the introduction of new ion-pairs, as well as the design of stabilising disulfide bridges and ligand binding sites, all offer the opportunity to produce proteins with enhanced stability properties.
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Affiliation(s)
- C R Middaugh
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Avenue, Lawrence, KS 66047, USA
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26
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Eijsink VGH, Bjørk A, Gåseidnes S, Sirevåg R, Synstad B, van den Burg B, Vriend G. Rational engineering of enzyme stability. J Biotechnol 2004; 113:105-20. [PMID: 15380651 DOI: 10.1016/j.jbiotec.2004.03.026] [Citation(s) in RCA: 326] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 02/16/2004] [Accepted: 03/04/2004] [Indexed: 11/19/2022]
Abstract
During the past 15 years there has been a continuous flow of reports describing proteins stabilized by the introduction of mutations. These reports span a period from pioneering rational design work on small enzymes such as T4 lysozyme and barnase to protein design, and directed evolution. Concomitantly, the purification and characterization of naturally occurring hyperstable proteins has added to our understanding of protein stability. Along the way, many strategies for rational protein stabilization have been proposed, some of which (e.g. entropic stabilization by introduction of prolines or disulfide bridges) have reasonable success rates. On the other hand, comparative studies and efforts in directed evolution have revealed that there are many mutational strategies that lead to high stability, some of which are not easy to define and rationalize. Recent developments in the field include increasing awareness of the importance of the protein surface for stability, as well as the notion that normally a very limited number of mutations can yield a large increase in stability. Another development concerns the notion that there is a fundamental difference between the "laboratory stability" of small pure proteins that unfold reversibly and completely at high temperatures and "industrial stability", which is usually governed by partial unfolding processes followed by some kind of irreversible inactivation process (e.g. aggregation). Provided that one has sufficient knowledge of the mechanism of thermal inactivation, successful and efficient rational stabilization of enzymes can be achieved.
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Affiliation(s)
- Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Agricultural University of Norway, PO Box 5040, N-1432 As.
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Strub C, Alies C, Lougarre A, Ladurantie C, Czaplicki J, Fournier D. Mutation of exposed hydrophobic amino acids to arginine to increase protein stability. BMC BIOCHEMISTRY 2004; 5:9. [PMID: 15251041 PMCID: PMC479692 DOI: 10.1186/1471-2091-5-9] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Accepted: 07/13/2004] [Indexed: 11/10/2022]
Abstract
BACKGROUND One strategy to increase the stability of proteins is to reduce the area of water-accessible hydrophobic surface. RESULTS In order to test it, we replaced 14 solvent-exposed hydrophobic residues of acetylcholinesterase by arginine. The stabilities of the resulting proteins were tested using denaturation by high temperature, organic solvents, urea and by proteolytic digestion. CONCLUSION Although the mutational effects were rather small, this strategy proved to be successful since half of the mutants showed an increased stability. This stability may originate from the suppression of unfavorable interactions of nonpolar residues with water or from addition of new hydrogen bonds with the solvent. Other mechanisms may also contribute to the increased stability observed with some mutants. For example, introduction of a charge at the surface of the protein may provide a new coulombic interaction on the protein surface.
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Affiliation(s)
- Caroline Strub
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
| | - Carole Alies
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
| | - Andrée Lougarre
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
| | - Caroline Ladurantie
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
| | - Jerzy Czaplicki
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
| | - Didier Fournier
- Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, 31077 Toulouse, France
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28
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Bordner AJ, Abagyan RA. Large-scale prediction of protein geometry and stability changes for arbitrary single point mutations. Proteins 2004; 57:400-13. [PMID: 15340927 DOI: 10.1002/prot.20185] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have developed a method to both predict the geometry and the relative stability of point mutants that may be used for arbitrary mutations. The geometry optimization procedure was first tested on a new benchmark of 2141 ordered pairs of X-ray crystal structures of proteins that differ by a single point mutation, the largest data set to date. An empirical energy function, which includes terms representing the energy contributions of the folded and denatured proteins and uses the predicted mutant side chain conformation, was fit to a training set consisting of half of a diverse set of 1816 experimental stability values for single point mutations in 81 different proteins. The data included a substantial number of small to large residue mutations not considered by previous prediction studies. After removing 22 (approximately 2%) outliers, the stability calculation gave a standard deviation of 1.08 kcal/mol with a correlation coefficient of 0.82. The prediction method was then tested on the remaining half of the experimental data, giving a standard deviation of 1.10 kcal/mol and covariance of 0.66 for 97% of the test set. A regression fit of the energy function to a subset of 137 mutants, for which both native and mutant structures were available, gave a prediction error comparable to that for the complete training set with predicted side chain conformations. We found that about half of the variation is due to conformation-independent residue contributions. Finally, a fit to the experimental stability data using these residue parameters exclusively suggests guidelines for improving protein stability in the absence of detailed structure information.
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Affiliation(s)
- A J Bordner
- The Scripps Research Institute, 10550 North Torrey Pines Rd., Mail TPC-28, San Diego, California, USA.
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29
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Schwehm JM, Fitch CA, Dang BN, García-Moreno E B, Stites WE. Changes in stability upon charge reversal and neutralization substitution in staphylococcal nuclease are dominated by favorable electrostatic effects. Biochemistry 2003; 42:1118-28. [PMID: 12549934 DOI: 10.1021/bi0266434] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single site mutations that reverse or neutralize a surface charge were made at 22 ionizable residues in staphylococcal nuclease. Unfolding free energies were obtained by guanidine hydrochloride denaturation. These data, in conjunction with previously obtained stabilities of the corresponding alanine mutants, unequivocally show that the dominant contribution to stability for virtually all of the wild-type side chains examined is the electrostatic effect associated with each residue's charged group. With only a few exceptions, these charges stabilize the native state, with an average loss of 0.5 kcal/mol of stability upon neutralization of a charge. When the charge is reversed, the average destabilization is doubled. Structure-based calculations of electrostatic free energy with the continuum method based on the finite difference solution to the linearized Poisson-Boltzmann equation reproduce the observed energetics when the polarizability in the protein interior is represented with a dielectric constant of 20. However, in some cases, large differences are found, giving insight into possible areas for improvement of the calculations. In particular, it appears that the assumptions made in the calculations about the absence of electrostatic interactions in the denatured state and the energetic consequences of dynamic fluctuations in the native state will have to be further explored.
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Affiliation(s)
- Jeffery M Schwehm
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701-1201, USA
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Ojennus DD, Lehto SE, Wuttke DS. Electrostatic interactions in the reconstitution of an SH2 domain from constituent peptide fragments. Protein Sci 2003; 12:44-55. [PMID: 12493827 PMCID: PMC2312404 DOI: 10.1110/ps.0227903] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Fragment complementation has been used to delineate the essential recognition elements for stable folding in Src homology 2 (SH2) domains by using NMR spectroscopy, alanine scanning, and surface plasmon resonance. The unfolded 9-kD and 5-kD peptide fragments formed by limited proteolytic digestion of the N-terminal SH2 domain from the p85alpha subunit of phosphatidylinositol 3'-kinase fold into an active native-like structure on interaction with one another. The corresponding 5-kD fragment of the homologous Src protein, however, was not capable of structurally complementing the p85 9-kD fragment, indicating that fragment complementation among these SH2 domains is sensitive to the sequence differences between the Src and p85 domains. Partial complementation and folding activity could be recovered with hybrid sequences of these SH2 domains. Complete alanine scanning of the 5-kD p85 fragment was used to identify the sequence recognition elements required for complex formation. The alanine substitutions in the p85 5-kD fragment that abolished binding affinity with the cognate 9-kD fragment correlate well with highly conserved residues among SH2 domains that are either integrally involved in core packing or found at the interface between fragments. Surprisingly, however, mutation of a nonconserved surface-exposed aspartic acid to alanine was found to have a significant effect on complementation. A single additional mutation of arginine to aspartic acid allowed for recovery of native structure and increased the thermal stability of the designed Src-p85 chimera by 18 degrees C. This modification appears to relieve an unfavorable surface electrostatic interaction, demonstrating the importance of surface charge interactions in protein stability.
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Affiliation(s)
- Deanna Dahlke Ojennus
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309-0215, USA
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31
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Ermolenko DN, Thomas ST, Aurora R, Gronenborn AM, Makhatadze GI. Hydrophobic interactions at the Ccap position of the C-capping motif of alpha-helices. J Mol Biol 2002; 322:123-35. [PMID: 12215419 DOI: 10.1016/s0022-2836(02)00734-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We investigated the possible role of residues at the Ccap position in an alpha-helix on protein stability. A set of 431 protein alpha-helices containing a C'-Gly from the Protein Data Bank (PDB) was analyzed, and the normalized frequencies for finding particular residues at the Ccap position, the average fraction of buried surface area, and the hydrogen bonding patterns of the Ccap residue side-chain were calculated. We found that on average the Ccap position is 70% buried and noted a significant correlation (R=0.8) between the relative burial of this residue and its hydrophobicity as defined by the Gibbs energy of transfer from octanol or cyclohexane to water. Ccap residues with polar side-chains are commonly involved in hydrogen bonding. The hydrogen bonding pattern is such that, the longer side-chains of Glu, Gln, Arg, Lys, His form hydrogen bonds with residues distal (>+/-4) in sequence, while the shorter side-chains of Asp, Asn, Ser, Thr exhibit hydrogen bonds with residues close in sequence (<+/-4), mainly involving backbone atoms. Experimentally we determined the thermodynamic propensities of residues at the Ccap position using the protein ubiquitin as a model system. We observed a large variation in the stability of the ubiquitin variants depending on the nature of the Ccap residue. Furthermore, the measured changes in stability of the ubiquitin variants correlate with the hydrophobicity of the Ccap residue. The experimental results, together with the statistical analysis of protein structures from the PDB, indicate that the key hydrophobic capping interactions between a helical residue (C3 or C4) and a residue outside the helix (C", C3' or C4') are frequently enhanced by the hydrophobic interactions with Ccap residues.
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Affiliation(s)
- Dmitri N Ermolenko
- Department of Biochemistry and Molecular Biology H171, Penn State University College of Medicine, Hershey, PA 17033-2390, USA
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32
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Gromiha MM, Oobatake M, Kono H, Uedaira H, Sarai A. Importance of mutant position in Ramachandran plot for predicting protein stability of surface mutations. Biopolymers 2002; 64:210-20. [PMID: 12115138 DOI: 10.1002/bip.10125] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Understanding the mechanisms by which mutations affect protein stability is one of the most important problems in molecular biology. In this work, we analyzed the relationship between changes in protein stability caused by surface mutations and changes in 49 physicochemical, energetic, and conformational properties of amino acid residues. We found that the hydration entropy was the major contributor to the stability of surface mutations in helical segments; other properties responsible for size and volume of molecule also correlated significantly with stability. Classification of coil mutations based on their locations in the (phi-psi) map improved the correlation significantly, demonstrating the existence of a relationship between stability and strain energy, which indicates that the role of strain energy is very important for the stability of surface mutations. We observed that the inclusion of sequence and structural information raised the correlation, indicating the influence of surrounding residues on the stability of surface mutations. Further, we examined the previously reported "inverse relationship" between stability and hydrophobicity, and observed that the inverse hydrophobic effect was generally applicable only to coil mutations. The present study leads to a simple method for predicting protein stability changes caused by amino acid substitutions, which will be useful for protein engineering in designing novel proteins with increased stability and altered function.
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Affiliation(s)
- M Michael Gromiha
- RIKEN Tsukuba Institute, Institute of Physical and Chemical Research, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
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33
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Funahashi J, Takano K, Yamagata Y, Yutani K. Positive contribution of hydration structure on the surface of human lysozyme to the conformational stability. J Biol Chem 2002; 277:21792-800. [PMID: 11927576 DOI: 10.1074/jbc.m110728200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Water molecules make a hydration structure with the network of hydrogen bonds, covering on the surface of proteins. To quantitatively estimate the contribution of the hydration structure to protein stability, a series of hydrophilic mutant human lysozymes (Val to Ser, Tyr, Asp, Asn, and Arg) modified at three different positions on the surface, which are located in the alpha-helix (Val-110), the beta-sheet (Val-2), and the loop (Val-74), were constructed. Their thermodynamic parameters of denaturation and crystal structures were examined by calorimetry and by x-ray crystallography at 100 K, respectively. The introduced polar residues made hydrogen bonds with protein atoms and/or water molecules, sometimes changing the hydration structure around the mutation site. Changes in the stability of the mutant proteins can be evaluated by a unique equation that considers the conformational changes resulting from the substitutions. Using this analysis, the relationship between the changes in the stabilities and the hydration structures for mutant human lysozymes substituted on the surface could be quantitatively estimated. The analysis indicated that the hydration structure on protein surface plays an important role in determining the conformational stability of the protein.
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Affiliation(s)
- Jun Funahashi
- Institute for Protein Research, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan
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34
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Angrand I, Serrano L, Lacroix E. Computer-assisted re-design of spectrin SH3 residue clusters. BIOMOLECULAR ENGINEERING 2001; 18:125-34. [PMID: 11566604 DOI: 10.1016/s1389-0344(01)00093-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have developed a protein design computer program, called Perla, which performs searches in sequence space to uncover optimal amino acid sequences for desired protein three-dimensional structures. Optimal sequences are localised at the minima of a sequence-structure energy landscape defined using a complex scoring function (an all-atom molecular mechanics force field plus statistical terms including entropy and solvation) measured with respect to a reference state simulating a denatured protein. Sequence choices eventually optimise side chain packing, secondary structure propensities, and hydrogen bonding and electrostatics interactions. Perla was used to re-design clusters of residues of the SH3 domain of alpha-spectrin. Several mutant proteins were produced and characterised. Some of our designed proteins have significantly higher stabilities (stability enhancements about 0.25, 0.70 and 1.0 kcal mol(-1)) than the wild-type protein. These successful protein re-designs, and similar examples found in the literature, establish the quality of the structure-based computational approach to protein design.
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Affiliation(s)
- I Angrand
- European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117, Heidelberg, Germany
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35
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Pace CN, Horn G, Hebert EJ, Bechert J, Shaw K, Urbanikova L, Scholtz JM, Sevcik J. Tyrosine hydrogen bonds make a large contribution to protein stability. J Mol Biol 2001; 312:393-404. [PMID: 11554795 DOI: 10.1006/jmbi.2001.4956] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to gain a better understanding of the contribution of hydrogen bonds by tyrosine -OH groups to protein stability. The amino acid sequences of RNases Sa and Sa3 are 69 % identical and each contains eight Tyr residues with seven at equivalent structural positions. We have measured the stability of the 16 tyrosine to phenylalanine mutants. For two equivalent mutants, the stability increases by 0.3 kcal/mol (RNase Sa Y30F) and 0.5 kcal/mol (RNase Sa3 Y33F) (1 kcal=4.184 kJ). For all of the other mutants, the stability decreases with the greatest decrease being 3.6 kcal/mol for RNase Sa Y52F. Seven of the 16 tyrosine residues form intramolecular hydrogen bonds and the average decrease in stability for these is 2.0(+/-1.0) kcal/mol. For the nine tyrosine residues that do not form intramolecular hydrogen bonds, the average decrease in stability is 0.4(+/-0.6) kcal/mol. Thus, most tyrosine -OH groups contribute favorably to protein stability even if they do not form intramolecular hydrogen bonds. Generally, the stability changes for equivalent positions in the two proteins are remarkably similar. Crystal structures were determined for two of the tyrosine to phenylalanine mutants of RNase Sa: Y80F (1.2 A), and Y86F (1.7 A). The structures are very similar to that of wild-type RNase Sa, and the hydrogen bonding partners of the tyrosine residues always form intermolecular hydrogen bonds to water in the mutants. These results provide further evidence that the hydrogen bonding and van der Waals interactions of polar groups in the tightly packed interior of folded proteins are more favorable than similar interactions with water in the unfolded protein, and that polar group burial makes a substantial contribution to protein stability.
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Affiliation(s)
- C N Pace
- Department of Medical Biochemistry and Genetics, Texas A&M University, College Station, 77843-1114, USA.
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36
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Zavodszky M, Chen CW, Huang JK, Zolkiewski M, Wen L, Krishnamoorthi R. Disulfide bond effects on protein stability: designed variants of Cucurbita maxima trypsin inhibitor-V. Protein Sci 2001; 10:149-60. [PMID: 11266603 PMCID: PMC2249841 DOI: 10.1110/ps.26801] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Attempts to increase protein stability by insertion of novel disulfide bonds have not always been successful. According to the two current models, cross-links enhance stability mainly through denatured state effects. We have investigated the effects of removal and addition of disulfide cross-links, protein flexibility in the vicinity of a cross-link, and disulfide loop size on the stability of Cucurbita maxima trypsin inhibitor-V (CMTI-V; 7 kD) by differential scanning calorimetry. CMTI-V offers the advantage of a large, flexible, and solvent-exposed loop not involved in extensive intra-molecular interactions. We have uncovered a negative correlation between retention time in hydrophobic column chromatography, a measure of protein hydrophobicity, and melting temperature (T(m)), an indicator of native state stabilization, for CMTI-V and its variants. In conjunction with the complete set of thermodynamic parameters of denaturation, this has led to the following deductions: (1) In the less stable, disulfide-removed C3S/C48S (Delta Delta G(d)(50 degrees C) = -4 kcal/mole; Delta T(m) = -22 degrees C), the native state is destabilized more than the denatured state; this also applies to the less-stable CMTI-V* (Delta Delta G(d)(50 degrees C) = -3 kcal/mole; Delta T(m) = -11 degrees C), in which the disulfide-containing loop is opened by specific hydrolysis of the Lys(44)-Asp(45) peptide bond; (2) In the less stable, disulfide-inserted E38C/W54C (Delta Delta G(d)(50 degrees C) = -1 kcal/mole; Delta T(m) = +2 degrees C), the denatured state is more stabilized than the native state; and (3) In the more stable, disulfide-engineered V42C/R52C (Delta Delta G(d)(50 degrees C) = +1 kcal/mole; Delta T(m) = +17 degrees C), the native state is more stabilized than the denatured state. These results show that a cross-link stabilizes both native and denatured states, and differential stabilization of the two states causes either loss or gain in protein stability. Removal of hydrogen bonds in the same flexible region of CMTI-V resulted in less destabilization despite larger changes in the enthalpy and entropy of denaturation. The effect of a cross-link on the denatured state of CMTI-V was estimated directly by means of a four-state thermodynamic cycle consisting of native and denatured states of CMTI-V and CMTI-V*. Overall, the results show that an enthalpy-entropy compensation accompanies disulfide bond effects and protein stabilization is profoundly modulated by altered hydrophobicity of both native and denatured states, altered flexibility near the cross-link, and residual structure in the denatured state.
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Affiliation(s)
- M Zavodszky
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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37
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Reiersen H, Rees AR. Sodium sulphate reactivates a protein A minidomain with a short elastin beta-turn. Biochem Biophys Res Commun 2000; 276:899-904. [PMID: 11027566 DOI: 10.1006/bbrc.2000.3588] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Elastin polymer sequences derived from muscle exhibit temperature and salt-induced reversible contractions and expansions. A folded and contracted beta-turn helical elastin structure is stabilised by increased intramolecular hydrophobic interactions. We have generated a switchable binding protein by inserting a typical elastin turn sequence, GVPGVG, between the two IgG-binding helices of an engineered globular minidomain from Protein A. This mutant showed increased binding of IgG-molecules compared to the wild-type sequence in the presence of sodium sulphate, as measured by surface plasmon resonance spectroscopy. Analysis by circular dichroism revealed a salt-induced folding of the mutant minidomain to a native type I beta-turn, likely stabilised as a result of the two interacting dehydrated valines across the beta-turn. Since sodium sulphate can be successfully used to regulate the folding/unfolding or binding/dissociation of this minidomain, this suggests an alternative protein purification method.
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Affiliation(s)
- H Reiersen
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom
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38
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Gromiha MM, Oobatake M, Kono H, Uedaira H, Sarai A. Importance of surrounding residues for protein stability of partially buried mutations. J Biomol Struct Dyn 2000; 18:281-95. [PMID: 11089649 DOI: 10.1080/07391102.2000.10506666] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
For understanding the factors influencing protein stability, we have analyzed the relationship between changes in protein stability caused by partially buried mutations and changes in 48 physico-chemical, energetic and conformational properties of amino acid residues. Multiple regression equations were derived to predict the stability of protein mutants and the efficiency of the method has been verified with both back-check and jack-knife tests. We observed a good agreement between experimental and computed stabilities. Further, we have analyzed the effect of sequence window length from 1 to 12 residues on each side of the mutated residue to include the sequence information for predicting protein stability and we found that the preferred window length for obtaining the highest correlation is different for each secondary structure; the preferred window length for helical, strand and coil mutations are, respectively, 0, 9 and 4 residues on both sides of the mutant residues. However, all the secondary structures have significant correlation for a window length of one residue on each side of the mutant position, implying the role of short-range interactions. Extraction of surrounding residue information for various distances (3 to 20A) around the mutant position showed the highest correlation at 8A, 6A and 7A, respectively, for mutations in helical, strand and coil segments. Overall, the information about the surrounding residues within the sphere of 7 to 8A, may explain better the stability in all subsets of partially buried mutations implying that this distance is sufficient to accommodate the residues influenced by major intramolecular interactions for the stability of protein structures.
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Affiliation(s)
- M M Gromiha
- RIKEN Tsukuba Institute, The Institute of Physical and Chemical Research, Ibaraki, Japan
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39
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Grimsley GR, Shaw KL, Fee LR, Alston RW, Huyghues-Despointes BM, Thurlkill RL, Scholtz JM, Pace CN. Increasing protein stability by altering long-range coulombic interactions. Protein Sci 1999; 8:1843-9. [PMID: 10493585 PMCID: PMC2144408 DOI: 10.1110/ps.8.9.1843] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
It is difficult to increase protein stability by adding hydrogen bonds or burying nonpolar surface. The results described here show that reversing the charge on a side chain on the surface of a protein is a useful way of increasing stability. Ribonuclease T1 is an acidic protein with a pI approximately 3.5 and a net charge of approximately -6 at pH 7. The side chain of Asp49 is hyperexposed, not hydrogen bonded, and 8 A from the nearest charged group. The stability of Asp49Ala is 0.5 kcal/mol greater than wild-type at pH 7 and 0.4 kcal/mol less at pH 2.5. The stability of Asp49His is 1.1 kcal/mol greater than wild-type at pH 6, where the histidine 49 side chain (pKa = 7.2) is positively charged. Similar results were obtained with ribonuclease Sa where Asp25Lys is 0.9 kcal/mol and Glu74Lys is 1.1 kcal/mol more stable than the wild-type enzyme. These results suggest that protein stability can be increased by improving the coulombic interactions among charged groups on the protein surface. In addition, the stability of RNase T1 decreases as more hydrophobic aromatic residues are substituted for Ala49, indicating a reverse hydrophobic effect.
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Affiliation(s)
- G R Grimsley
- Department of Medical Biochemistry and Genetics, Texas A&M University, College Station 77843-1114, USA
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40
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Cordes MH, Sauer RT. Tolerance of a protein to multiple polar-to-hydrophobic surface substitutions. Protein Sci 1999; 8:318-25. [PMID: 10048325 PMCID: PMC2144263 DOI: 10.1110/ps.8.2.318] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Hydrophobic substitutions at solvent-exposed positions in two alpha-helical regions of the bacteriophage P22 Arc repressor were introduced by combinatorial mutagenesis. In helix A, hydrophobic residues were tolerated individually at each of the five positions examined, but multiple substitutions were poorly tolerated as shown by the finding that mutants with more than two additional hydrophobic residues were biologically inactive. Several inactive helix A variants were purified and found to have reduced thermal stability relative to wild-type Arc, with a rough correlation between the number of polar-to-hydrophobic substitutions and the magnitude of the stability defect. Quite different results were obtained in helix B, where variants with as many as five polar-to-hydrophobic substitutions were found to be biologically active and one variant with three hydrophobic substitutions had a t(m) 6 degrees C higher than wild-type. By contrast, a helix A mutant with three similar polar-to-hydrophobic substitutions was 23 degrees C less stable than wild-type. Also, one set of three polar-to-hydrophobic substitutions in helix B was tolerated when introduced into the wild-type background but not when introduced into an equally active mutant having a nearly identical structure. Context effects occur both when comparing different regions of the same protein and when comparing the same region in two different homologues.
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Affiliation(s)
- M H Cordes
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139 USA
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