1
|
Chandrasekaran SN, Das J, Dokholyan NV, Carter CW. Microcalorimetry reveals multi-state thermal denaturation of G. stearothermophilus tryptophanyl-tRNA synthetase. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2023; 10:044301. [PMID: 37476003 PMCID: PMC10356175 DOI: 10.1063/4.0000181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023]
Abstract
Mechanistic studies of Geobacillus stearothermophilus tryptophanyl-tRNA synthetase (TrpRS) afford an unusually detailed description-the escapement mechanism-for the distinct steps coupling catalysis to domain motion, efficiently converting the free energy of ATP hydrolysis into biologically useful alternative forms of information and work. Further elucidation of the escapement mechanism requires understanding thermodynamic linkages between domain configuration and conformational stability. To that end, we compare experimental thermal melting of fully liganded and apo TrpRS with a computational simulation of the melting of its fully liganded form. The simulation also provides important structural cameos at successively higher temperatures, enabling more confident interpretation. Experimental and simulated melting both proceed through a succession of three transitions at successively higher temperature. The low-temperature transition occurs at approximately the growth temperature of the organism and so may be functionally relevant but remains too subtle to characterize structurally. Structural metrics from the simulation imply that the two higher-temperature transitions entail forming a molten globular state followed by unfolding of secondary structures. Ligands that stabilize the enzyme in a pre-transition (PreTS) state compress the temperature range over which these transitions occur and sharpen the transitions to the molten globule and fully denatured states, while broadening the low-temperature transition. The experimental enthalpy changes provide a key parameter necessary to convert changes in melting temperature of combinatorial mutants into mutationally induced conformational free energy changes. The TrpRS urzyme, an excerpted model representing an early ancestral form, containing virtually the entire catalytic apparatus, remains largely intact at the highest simulated temperatures.
Collapse
Affiliation(s)
| | - Jhuma Das
- Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Nikolay V. Dokholyan
- Department of Pharmacology and Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Charles W. Carter
- Department of Biophysics and Biochemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
2
|
Weinreb V, Weinreb G, Carter CW. High-throughput thermal denaturation of tryptophanyl-tRNA synthetase combinatorial mutants reveals high-order energetic coupling determinants of conformational stability. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2023; 10:044304. [PMID: 37637481 PMCID: PMC10449480 DOI: 10.1063/4.0000182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/13/2023] [Indexed: 08/29/2023]
Abstract
Landscape descriptions provide a framework for identifying functionally significant dynamic linkages in proteins but cannot supply details. Rate measurements of combinatorial mutations can implicate dynamic linkages in catalysis. A major difficulty is filtering dynamic linkages from the vastly more numerous static interactions that stabilize domain folding. The Geobacillus stearothermophilus (TrpRS) D1 switch is such a dynamic packing motif; it links domain movement to catalysis and specificity. We describe Thermofluor and far UV circular dichroism melting curves for all 16 D1 switch variants to determine their higher-order impact on unliganded TrpRS stability. A prominent transition at intermediate temperatures in TrpRS thermal denaturation is molten globule formation. Combinatorial analysis of thermal melting transcends the protein landscape in four significant respects: (i) bioinformatic methods identify dynamic linkages from coordinates of multiple conformational states. (ii) Relative mutant melting temperatures, δTM, are proportional to free energy changes. (iii) Structural analysis of thermal melting implicates unexpected coupling between the D1 switch packing and regions of high local frustration. Those segments develop molten globular characteristics at the point of greatest complementarity to the chemical transition state and are the first TrpRS structures to melt. (iv) Residue F37 stabilizes both native and molten globular states; its higher-order interactions modify the relative intrinsic impacts of mutations to other D1 switch residues from those estimated for single point mutants. The D1 switch is a central component of an escapement mechanism essential to free energy transduction. These conclusions begin to relate the escapement mechanism to differential TrpRS conformational stabilities.
Collapse
Affiliation(s)
- Violetta Weinreb
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260, USA
| | | | - Charles W. Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260, USA
| |
Collapse
|
3
|
Gupta MN, Uversky VN. Pre-Molten, Wet, and Dry Molten Globules en Route to the Functional State of Proteins. Int J Mol Sci 2023; 24:ijms24032424. [PMID: 36768742 PMCID: PMC9916686 DOI: 10.3390/ijms24032424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Transitions between the unfolded and native states of the ordered globular proteins are accompanied by the accumulation of several intermediates, such as pre-molten globules, wet molten globules, and dry molten globules. Structurally equivalent conformations can serve as native functional states of intrinsically disordered proteins. This overview captures the characteristics and importance of these molten globules in both structured and intrinsically disordered proteins. It also discusses examples of engineered molten globules. The formation of these intermediates under conditions of macromolecular crowding and their interactions with nanomaterials are also reviewed.
Collapse
Affiliation(s)
- Munishwar Nath Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
- Correspondence: ; Tel.: +1-813-494-5816
| |
Collapse
|
4
|
Piersimoni L, Abd El Malek M, Bhatia T, Bender J, Brankatschk C, Calvo Sánchez J, Dayhoff GW, Di Ianni A, Figueroa Parra JO, Garcia-Martinez D, Hesselbarth J, Köppen J, Lauth LM, Lippik L, Machner L, Sachan S, Schmidt L, Selle R, Skalidis I, Sorokin O, Ubbiali D, Voigt B, Wedler A, Wei AAJ, Zorn P, Dunker AK, Köhn M, Sinz A, Uversky VN. Lighting up Nobel Prize-winning studies with protein intrinsic disorder. Cell Mol Life Sci 2022; 79:449. [PMID: 35882686 PMCID: PMC11072364 DOI: 10.1007/s00018-022-04468-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/18/2022] [Accepted: 07/04/2022] [Indexed: 11/03/2022]
Abstract
Intrinsically disordered proteins and regions (IDPs and IDRs) and their importance in biology are becoming increasingly recognized in biology, biochemistry, molecular biology and chemistry textbooks, as well as in current protein science and structural biology curricula. We argue that the sequence → dynamic conformational ensemble → function principle is of equal importance as the classical sequence → structure → function paradigm. To highlight this point, we describe the IDPs and/or IDRs behind the discoveries associated with 17 Nobel Prizes, 11 in Physiology or Medicine and 6 in Chemistry. The Nobel Laureates themselves did not always mention that the proteins underlying the phenomena investigated in their award-winning studies are in fact IDPs or contain IDRs. In several cases, IDP- or IDR-based molecular functions have been elucidated, while in other instances, it is recognized that the respective protein(s) contain IDRs, but the specific IDR-based molecular functions have yet to be determined. To highlight the importance of IDPs and IDRs as general principle in biology, we present here illustrative examples of IDPs/IDRs in Nobel Prize-winning mechanisms and processes.
Collapse
Affiliation(s)
- Lolita Piersimoni
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Marina Abd El Malek
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Twinkle Bhatia
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Julian Bender
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Christin Brankatschk
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Jaime Calvo Sánchez
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Guy W Dayhoff
- Department of Chemistry, College of Art and Sciences, University of South Florida, Tampa, FL, 33620, USA
| | - Alessio Di Ianni
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | | | - Dailen Garcia-Martinez
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Julia Hesselbarth
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Janett Köppen
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Luca M Lauth
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Laurin Lippik
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Lisa Machner
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Shubhra Sachan
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Lisa Schmidt
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Robin Selle
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Ioannis Skalidis
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Oleksandr Sorokin
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Daniele Ubbiali
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Bruno Voigt
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Alice Wedler
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Alan An Jung Wei
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Peter Zorn
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Alan Keith Dunker
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Marcel Köhn
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany.
| | - Andrea Sinz
- Research Training Group RTG2467, Martin Luther University Halle-Wittenberg, 06120, Halle (Saale), Germany.
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
| |
Collapse
|
5
|
Kulkarni P, Bhattacharya S, Achuthan S, Behal A, Jolly MK, Kotnala S, Mohanty A, Rangarajan G, Salgia R, Uversky V. Intrinsically Disordered Proteins: Critical Components of the Wetware. Chem Rev 2022; 122:6614-6633. [PMID: 35170314 PMCID: PMC9250291 DOI: 10.1021/acs.chemrev.1c00848] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Despite the wealth of knowledge gained about intrinsically disordered proteins (IDPs) since their discovery, there are several aspects that remain unexplored and, hence, poorly understood. A living cell is a complex adaptive system that can be described as a wetware─a metaphor used to describe the cell as a computer comprising both hardware and software and attuned to logic gates─capable of "making" decisions. In this focused Review, we discuss how IDPs, as critical components of the wetware, influence cell-fate decisions by wiring protein interaction networks to keep them minimally frustrated. Because IDPs lie between order and chaos, we explore the possibility that they can be modeled as attractors. Further, we discuss how the conformational dynamics of IDPs manifests itself as conformational noise, which can potentially amplify transcriptional noise to stochastically switch cellular phenotypes. Finally, we explore the potential role of IDPs in prebiotic evolution, in forming proteinaceous membrane-less organelles, in the origin of multicellularity, and in protein conformation-based transgenerational inheritance of acquired characteristics. Together, these ideas provide a new conceptual framework to discern how IDPs may perform critical biological functions despite their lack of structure.
Collapse
Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
- Address for correspondence: Prakash Kulkarni, Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, , Vladimir N. Uversky, Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612,
| | - Supriyo Bhattacharya
- Integrative Genomics Core, City of Hope National Medical Center, Duarte, CA, USA
| | - Srisairam Achuthan
- Division of Research Informatics, Center for Informatics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Amita Behal
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Sourabh Kotnala
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
- Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Vladimir Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
- Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow region 141700, Russia
- Address for correspondence: Prakash Kulkarni, Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, , Vladimir N. Uversky, Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612,
| |
Collapse
|
6
|
Makarov M, Meng J, Tretyachenko V, Srb P, Březinová A, Giacobelli VG, Bednárová L, Vondrášek J, Dunker AK, Hlouchová K. Enzyme catalysis prior to aromatic residues: Reverse engineering of a dephospho-CoA kinase. Protein Sci 2021; 30:1022-1034. [PMID: 33739538 PMCID: PMC8040869 DOI: 10.1002/pro.4068] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/07/2022]
Abstract
The wide variety of protein structures and functions results from the diverse properties of the 20 canonical amino acids. The generally accepted hypothesis is that early protein evolution was associated with enrichment of a primordial alphabet, thereby enabling increased protein catalytic efficiencies and functional diversification. Aromatic amino acids were likely among the last additions to genetic code. The main objective of this study was to test whether enzyme catalysis can occur without the aromatic residues (aromatics) by studying the structure and function of dephospho-CoA kinase (DPCK) following aromatic residue depletion. We designed two variants of a putative DPCK from Aquifex aeolicus by substituting (a) Tyr, Phe and Trp or (b) all aromatics (including His). Their structural characterization indicates that substituting the aromatics does not markedly alter their secondary structures but does significantly loosen their side chain packing and increase their sizes. Both variants still possess ATPase activity, although with 150-300 times lower efficiency in comparison with the wild-type phosphotransferase activity. The transfer of the phosphate group to the dephospho-CoA substrate becomes heavily uncoupled and only the His-containing variant is still able to perform the phosphotransferase reaction. These data support the hypothesis that proteins in the early stages of life could support catalytic activities, albeit with low efficiencies. An observed significant contraction upon ligand binding is likely important for appropriate organization of the active site. Formation of firm hydrophobic cores, which enable the assembly of stably structured active sites, is suggested to provide a selective advantage for adding the aromatic residues.
Collapse
Affiliation(s)
- Mikhail Makarov
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Department of Biochemistry, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Jingwei Meng
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Vyacheslav Tretyachenko
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Department of Biochemistry, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Pavel Srb
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Anna Březinová
- Proteomics Core Facility, BIOCEV, Faculty of Science, Charles UniversityPragueCzech Republic
| | | | - Lucie Bednárová
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Jiří Vondrášek
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - A. Keith Dunker
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| |
Collapse
|
7
|
Martí S. QMCube (QM 3 ): An all-purpose suite for multiscale QM/MM calculations. J Comput Chem 2021; 42:447-457. [PMID: 33337551 DOI: 10.1002/jcc.26465] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/03/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022]
Abstract
QMCube (QM3 ) is a suite written in the Python programming language, initially focused on multiscale QM/MM simulations of biological systems, but open enough to address other kinds of problems. It allows the user to combine highly efficient QM and MM programs, providing unified access to a wide range of computational methods. The suite also supplies additional modules with extra functionalities. These modules facilitate common tasks such as performing the setup of the models or process the data generated during the simulations. The design of QM3 has been carried out considering the least number of external dependencies (only an algebra library, already included in the distribution), which makes it extremely portable. Also, the modular structure of the suite should help to expand and develop new computational methods.
Collapse
Affiliation(s)
- Sergio Martí
- Departament de Química Física i Analítica, Universitat Jaume I, Castellón, Spain
| |
Collapse
|
8
|
Carter CW, Wills PR. Reciprocally-Coupled Gating: Strange Loops in Bioenergetics, Genetics, and Catalysis. Biomolecules 2021; 11:265. [PMID: 33670192 PMCID: PMC7916928 DOI: 10.3390/biom11020265] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/12/2022] Open
Abstract
Bioenergetics, genetic coding, and catalysis are all difficult to imagine emerging without pre-existing historical context. That context is often posed as a "Chicken and Egg" problem; its resolution is concisely described by de Grasse Tyson: "The egg was laid by a bird that was not a chicken". The concision and generality of that answer furnish no details-only an appropriate framework from which to examine detailed paradigms that might illuminate paradoxes underlying these three life-defining biomolecular processes. We examine experimental aspects here of five examples that all conform to the same paradigm. In each example, a paradox is resolved by coupling "if, and only if" conditions for reciprocal transitions between levels, such that the consequent of the first test is the antecedent for the second. Each condition thus restricts fluxes through, or "gates" the other. Reciprocally-coupled gating, in which two gated processes constrain one another, is self-referential, hence maps onto the formal structure of "strange loops". That mapping uncovers two different kinds of forces that may help unite the axioms underlying three phenomena that distinguish biology from chemistry. As a physical analog for Gödel's logic, biomolecular strange-loops provide a natural metaphor around which to organize a large body of experimental data, linking biology to information, free energy, and the second law of thermodynamics.
Collapse
Affiliation(s)
- Charles W. Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7260, USA
| | - Peter R. Wills
- Department of Physics and Te Ao Marama Centre for Fundamental Inquiry, University of Auckland, PB 92019, Auckland 1142, New Zealand;
| |
Collapse
|
9
|
Structure and function of naturally evolved de novo proteins. Curr Opin Struct Biol 2021; 68:175-183. [PMID: 33567396 DOI: 10.1016/j.sbi.2020.11.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/16/2020] [Accepted: 11/27/2020] [Indexed: 01/05/2023]
Abstract
Comparative evolutionary genomics has revealed that novel protein coding genes can emerge randomly from non-coding DNA. While most of the myriad of transcripts which continuously emerge vanish rapidly, some attain regulatory regions, become translated and survive. More surprisingly, sequence properties of de novo proteins are almost indistinguishable from randomly obtained sequences, yet de novo proteins may gain functions and integrate into eukaryotic cellular networks quite easily. We here discuss current knowledge on de novo proteins, their structures, functions and evolution. Since the existence of de novo proteins seems at odds with decade-long attempts to construct proteins with novel structures and functions from scratch, we suggest that a better understanding of de novo protein evolution may fuel new strategies for protein design.
Collapse
|
10
|
Fahrig-Kamarauskait J, Würth-Roderer K, Thorbjørnsrud HV, Mailand S, Krengel U, Kast P. Evolving the naturally compromised chorismate mutase from Mycobacterium tuberculosis to top performance. J Biol Chem 2020; 295:17514-17534. [PMID: 33453995 PMCID: PMC7762937 DOI: 10.1074/jbc.ra120.014924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/08/2020] [Indexed: 11/06/2022] Open
Abstract
Chorismate mutase (CM), an essential enzyme at the branch-point of the shikimate pathway, is required for the biosynthesis of phenylalanine and tyrosine in bacteria, archaea, plants, and fungi. MtCM, the CM from Mycobacterium tuberculosis, has less than 1% of the catalytic efficiency of a typical natural CM and requires complex formation with 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase for high activity. To explore the full potential of MtCM for catalyzing its native reaction, we applied diverse iterative cycles of mutagenesis and selection, thereby raising kcat/Km 270-fold to 5 × 105m−1s−1, which is even higher than for the complex. Moreover, the evolutionarily optimized autonomous MtCM, which had 11 of its 90 amino acids exchanged, was stabilized compared with its progenitor, as indicated by a 9 °C increase in melting temperature. The 1.5 Å crystal structure of the top-evolved MtCM variant reveals the molecular underpinnings of this activity boost. Some acquired residues (e.g. Pro52 and Asp55) are conserved in naturally efficient CMs, but most of them lie beyond the active site. Our evolutionary trajectories reached a plateau at the level of the best natural enzymes, suggesting that we have exhausted the potential of MtCM. Taken together, these findings show that the scaffold of MtCM, which naturally evolved for mediocrity to enable inter-enzyme allosteric regulation of the shikimate pathway, is inherently capable of high activity.
Collapse
Affiliation(s)
| | | | | | - Susanne Mailand
- Laboratory of Organic Chemistry, ETH Zurich, Zurich, Switzerland
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway.
| | - Peter Kast
- Laboratory of Organic Chemistry, ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
11
|
Abstract
Enzymes are predominantly proteins able to effectively and selectively catalyze highly complex biochemical reactions in mild reaction conditions. Nevertheless, they are limited to the arsenal of reactions that have emerged during natural evolution in compliance with their intrinsic nature, three-dimensional structures and dynamics. They optimally work in physiological conditions for a limited range of reactions, and thus exhibit a low tolerance for solvent and temperature conditions. The de novo design of synthetic highly stable enzymes able to catalyze a broad range of chemical reactions in variable conditions is a great challenge, which requires the development of programmable and finely tunable artificial tools. Interestingly, over the last two decades, chemists developed protein secondary structure mimics to achieve some desirable features of proteins, which are able to interfere with the biological processes. Such non-natural oligomers, so called foldamers, can adopt highly stable and predictable architectures and have extensively demonstrated their attractiveness for widespread applications in fields from biomedical to material science. Foldamer science was more recently considered to provide original solutions to the de novo design of artificial enzymes. This review covers recent developments related to peptidomimetic foldamers with catalytic properties and the principles that have guided their design.
Collapse
|
12
|
Wang T, Yang Y, Feng W, Wang R, Chen Z. Co-folding of hydrophobic rice proteins and shellac in hydrophilic binary microstructures for cellular uptake of apigenin. Food Chem 2020; 309:125695. [DOI: 10.1016/j.foodchem.2019.125695] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 02/06/2023]
|
13
|
He J, Chen Z, Gu Y, Li Y, Wang R, Gao Y, Feng W, Wang T. Hydrophilic co-assemblies of two hydrophobic biomolecules improving the bioavailability of silybin. Food Funct 2020; 11:10828-10838. [DOI: 10.1039/d0fo01882a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Benefitting from the versatility and biocompatibility of food sourced materials, the construction of hybrid structures via their molecular interplay generates novel platforms with unexpected properties.
Collapse
Affiliation(s)
- Jian He
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Zhengxing Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Yao Gu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Ya'nan Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Ren Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Yuan Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Wei Feng
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| | - Tao Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology
- Ministry of Education; National Engineering Laboratory for Cereal Fermentation Technology; Jiangsu Provincial Research Centre for Bioactive Product Processing Technology; and School of Food Science and Technology
- Jiangnan University
- Wuxi 214122
- China
| |
Collapse
|
14
|
Kulkarni P, Uversky VN. Intrinsically Disordered Proteins and the Janus Challenge. Biomolecules 2018; 8:biom8040179. [PMID: 30567293 PMCID: PMC6315817 DOI: 10.3390/biom8040179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 12/24/2022] Open
Abstract
To gain a new insight into the role of proteins in the origin of life on Earth, we present the Janus Challenge: identify an intrinsically disordered protein (IDP), naturally occurring or synthetic, that has catalytic activity. For example, such a catalytic IDP may perform condensation reactions to catalyze a peptide bond or a phosphodiester bond formation utilizing natural/un-natural amino acids or nucleotides, respectively. The IDP may also have autocatalytic, de novo synthesis, or self-replicative activity. Meeting this challenge may not only shed new light and provide an alternative to the RNA world hypothesis, but it may also serve as an impetus for technological advances with important biomedical applications.
Collapse
Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA 91010, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
- Laboratory of New methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia.
| |
Collapse
|
15
|
Kulkarni P, Uversky VN. Intrinsically Disordered Proteins: The Dark Horse of the Dark Proteome. Proteomics 2018; 18:e1800061. [DOI: 10.1002/pmic.201800061] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/07/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research; City of Hope National Medical Center; Duarte CA 91010 USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine; Morsani College of Medicine; University of South Florida; Tampa FL 33612 USA
- Laboratory of New methods in Biology; Institute for Biological Instrumentation; Russian Academy of Sciences; Pushchino Moscow Region 142290 Russia
| |
Collapse
|
16
|
Bychkova VE, Semisotnov GV, Balobanov VA, Finkelstein AV. The Molten Globule Concept: 45 Years Later. BIOCHEMISTRY (MOSCOW) 2018; 83:S33-S47. [DOI: 10.1134/s0006297918140043] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
17
|
Singh MI, Jain V. Identification and Characterization of an Inside-Out Folding Intermediate of T4 Phage Sliding Clamp. Biophys J 2017; 113:1738-1749. [PMID: 29045868 DOI: 10.1016/j.bpj.2017.08.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/15/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022] Open
Abstract
Protein folding process involves formation of transiently occurring intermediates that are difficult to isolate and characterize. It is both necessary and interesting to characterize the structural conformations adopted by these intermediates, also called molten globules (MG), to understand protein folding. Here, we investigated the equilibrium (un)folding intermediate state of T4 phage gene product 45 (gp45, also known as DNA polymerase processivity factor or sliding clamp) obtained during chemical denaturation. We show that gp45 undergoes substantial conformational rearrangement during unfolding and forms an expanded dry-MG. By monitoring the fluorescence of tryptophans that were strategically introduced at various sites, we demonstrate that the urea-treated molecule has its surface residues flip inside the core, and closely placed residues move farther. We were also able to isolate and purify the MG form of gp45 in native condition (i.e., nondenaturing buffer, at physiological pH and temperature); characteristics of this purified molecule substantially match with urea-treated wild-type gp45. To the best of our knowledge, this is one of the few reports that demonstrate the isolation and purification of a protein folding intermediate in native condition. We believe that our work not only allows us to dissect the process of protein folding, but will also help in the designing of folding inhibitors against sliding clamps to treat a wide variety of diseases from bacterial infection to cancer, due to the vast presence of clamps in all the domains of life.
Collapse
Affiliation(s)
- Manika Indrajit Singh
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India
| | - Vikas Jain
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India.
| |
Collapse
|
18
|
Foldability of a Natural De Novo Evolved Protein. Structure 2017; 25:1687-1696.e4. [PMID: 29033289 DOI: 10.1016/j.str.2017.09.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 07/22/2017] [Accepted: 09/15/2017] [Indexed: 12/13/2022]
Abstract
The de novo evolution of protein-coding genes from noncoding DNA is emerging as a source of molecular innovation in biology. Studies of random sequence libraries, however, suggest that young de novo proteins will not fold into compact, specific structures typical of native globular proteins. Here we show that Bsc4, a functional, natural de novo protein encoded by a gene that evolved recently from noncoding DNA in the yeast S. cerevisiae, folds to a partially specific three-dimensional structure. Bsc4 forms soluble, compact oligomers with high β sheet content and a hydrophobic core, and undergoes cooperative, reversible denaturation. Bsc4 lacks a specific quaternary state, however, existing instead as a continuous distribution of oligomer sizes, and binds dyes indicative of amyloid oligomers or molten globules. The combination of native-like and non-native-like properties suggests a rudimentary fold that could potentially act as a functional intermediate in the emergence of new folded proteins de novo.
Collapse
|
19
|
Li J, Xie Y, Wang R, Fang Z, Fang W, Zhang X, Xiao Y. Mechanism of salt-induced activity enhancement of a marine-derived laccase, Lac15. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 47:225-236. [PMID: 28875401 DOI: 10.1007/s00249-017-1251-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/07/2017] [Accepted: 08/23/2017] [Indexed: 10/18/2022]
Abstract
Laccase (benzenediol: oxygen oxidoreductases, EC1.10.3.2) is a multi-copper oxidase capable of oxidizing a variety of phenolic and other aromatic organic compounds. The catalytic power of laccase makes it an attractive candidate for potential applications in many areas of industry including biodegradation of organic pollutants and synthesis of novel drugs. Most laccases are vulnerable to high salt and have limited applications. However, some laccases are not only tolerant to but also activated by certain concentrations of salt and thus have great application potential. The mechanisms of salt-induced activity enhancement of laccases are unclear as yet. In this study, we used dynamic light scattering, size exclusion chromatography, analytical ultracentrifugation, intrinsic fluorescence emission, circular dichroism, ultraviolet-visible light absorption, and an enzymatic assay to investigate the potential correlation between the structure and activity of the marine-derived laccase, Lac15, whose activity is promoted by low concentrations of NaCl. The results showed that low concentrations of NaCl exert little influence on the protein structure, which was partially folded in the absence of the salt; moreover, the partially folded rather than the fully folded state seemed to be favorable for enzyme activity, and this partially folded state was distinctive from the so-called 'molten globule' occasionally observed in active enzymes. More data indicated that salt might promote laccase activity through mechanisms involving perturbation of specific local sites rather than a change in global structure. Potential binding sites for chloride ions and their roles in enzyme activity promotion are proposed.
Collapse
Affiliation(s)
- Jie Li
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China
| | - Yanan Xie
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China
| | - Rui Wang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China
| | - Zemin Fang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China
| | - Wei Fang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China.,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China
| | - Xuecheng Zhang
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China. .,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China. .,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China.
| | - Yazhong Xiao
- School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei, 230601, Anhui, China. .,Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, 111 Jiulong Road, Hefei, 230601, Anhui, China. .,Anhui Key Laboratory of Modern Biomanufacturing, 111 Jiulong Road, Hefei, 230601, Anhui, China.
| |
Collapse
|
20
|
Pohorille A, Wilson MA, Shannon G. Flexible Proteins at the Origin of Life. Life (Basel) 2017; 7:E23. [PMID: 28587235 PMCID: PMC5492145 DOI: 10.3390/life7020023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/10/2017] [Accepted: 05/24/2017] [Indexed: 11/17/2022] Open
Abstract
Almost all modern proteins possess well-defined, relatively rigid scaffolds that provide structural preorganization for desired functions. Such scaffolds require the sufficient length of a polypeptide chain and extensive evolutionary optimization. How ancestral proteins attained functionality, even though they were most likely markedly smaller than their contemporary descendants, remains a major, unresolved question in the origin of life. On the basis of evidence from experiments and computer simulations, we argue that at least some of the earliest water-soluble and membrane proteins were markedly more flexible than their modern counterparts. As an example, we consider a small, evolved in vitro ligase, based on a novel architecture that may be the archetype of primordial enzymes. The protein does not contain a hydrophobic core or conventional elements of the secondary structure characteristic of modern water-soluble proteins, but instead is built of a flexible, catalytic loop supported by a small hydrophilic core containing zinc atoms. It appears that disorder in the polypeptide chain imparts robustness to mutations in the protein core. Simple ion channels, likely the earliest membrane protein assemblies, could also be quite flexible, but still retain their functionality, again in contrast to their modern descendants. This is demonstrated in the example of antiamoebin, which can serve as a useful model of small peptides forming ancestral ion channels. Common features of the earliest, functional protein architectures discussed here include not only their flexibility, but also a low level of evolutionary optimization and heterogeneity in amino acid composition and, possibly, the type of peptide bonds in the protein backbone.
Collapse
Affiliation(s)
- Andrew Pohorille
- Exobiology Branch, MS 239-4, NASA Ames Research Center, Moffett Field, CA 94035, USA.
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94132, USA.
| | - Michael A Wilson
- Exobiology Branch, MS 239-4, NASA Ames Research Center, Moffett Field, CA 94035, USA.
- SETI Institute, 189 N Bernardo Ave #200, Mountain View, CA 94043, USA.
| | - Gareth Shannon
- Exobiology Branch, MS 239-4, NASA Ames Research Center, Moffett Field, CA 94035, USA.
- NASA Postdoctoral Program Fellow, NASA Ames Research Center, Moffett Field, CA 94035, USA.
| |
Collapse
|
21
|
Warshel A, Bora RP. Perspective: Defining and quantifying the role of dynamics in enzyme catalysis. J Chem Phys 2017; 144:180901. [PMID: 27179464 DOI: 10.1063/1.4947037] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Enzymes control chemical reactions that are key to life processes, and allow them to take place on the time scale needed for synchronization between the relevant reaction cycles. In addition to general interest in their biological roles, these proteins present a fundamental scientific puzzle, since the origin of their tremendous catalytic power is still unclear. While many different hypotheses have been put forward to rationalize this, one of the proposals that has become particularly popular in recent years is the idea that dynamical effects contribute to catalysis. Here, we present a critical review of the dynamical idea, considering all reasonable definitions of what does and does not qualify as a dynamical effect. We demonstrate that no dynamical effect (according to these definitions) has ever been experimentally shown to contribute to catalysis. Furthermore, the existence of non-negligible dynamical contributions to catalysis is not supported by consistent theoretical studies. Our review is aimed, in part, at readers with a background in chemical physics and biophysics, and illustrates that despite a substantial body of experimental effort, there has not yet been any study that consistently established a connection between an enzyme's conformational dynamics and a significant increase in the catalytic contribution of the chemical step. We also make the point that the dynamical proposal is not a semantic issue but a well-defined scientific hypothesis with well-defined conclusions.
Collapse
Affiliation(s)
- Arieh Warshel
- Department of Chemistry, University of Southern California, SGM 418, 3620 McClintock Avenue, Los Angeles, California 90089, USA
| | - Ram Prasad Bora
- Department of Chemistry, University of Southern California, SGM 418, 3620 McClintock Avenue, Los Angeles, California 90089, USA
| |
Collapse
|
22
|
Fisher AB. Peroxiredoxin 6 in the repair of peroxidized cell membranes and cell signaling. Arch Biochem Biophys 2017; 617:68-83. [PMID: 27932289 PMCID: PMC5810417 DOI: 10.1016/j.abb.2016.12.003] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 12/02/2016] [Accepted: 12/03/2016] [Indexed: 12/12/2022]
Abstract
Peroxiredoxin 6 represents a widely distributed group of peroxiredoxins that contain a single conserved cysteine in the protein monomer (1-cys Prdx). The cys when oxidized to the sulfenic form is reduced with glutathione (GSH) catalyzed by the π isoform of GSH-S-transferase. Three enzymatic activities of the protein have been described:1) peroxidase with H2O2, short chain hydroperoxides, and phospholipid hydroperoxides as substrates; 2) phospholipase A2 (PLA2); and 3) lysophosphatidylcholine acyl transferase (LPCAT). These activities have important physiological roles in antioxidant defense, turnover of cellular phospholipids, and the generation of superoxide anion via initiation of the signaling cascade for activation of NADPH oxidase (type 2). The ability of Prdx6 to reduce peroxidized cell membrane phospholipids (peroxidase activity) and also to replace the oxidized sn-2 fatty acyl group through hydrolysis/reacylation (PLA2 and LPCAT activities) provides a complete system for the repair of peroxidized cell membranes.
Collapse
Affiliation(s)
- Aron B Fisher
- Institute for Environmental Medicine of the Department of Physiology, University of Pennsylvania, 3620 Hamilton Walk, 1 John Morgan Building, Philadelphia, PA, United States.
| |
Collapse
|
23
|
Parray ZA, Shahid S, Ahmad F, Hassan MI, Islam A. Characterization of intermediate state of myoglobin in the presence of PEG 10 under physiological conditions. Int J Biol Macromol 2017; 99:241-248. [PMID: 28242330 DOI: 10.1016/j.ijbiomac.2017.02.084] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 01/24/2017] [Accepted: 02/22/2017] [Indexed: 11/28/2022]
Abstract
The macromolecular crowding progressively has been gaining prominence in recent years as it acts as a sword with double-edge on protein stability and folding, i.e., showing assorted results of having both stabilizing and destabilizing effects. We studied the effects of different concentrations of polyethylene glycol (PEG-10) on structure and stability of myoglobin. The tertiary structure of myoglobin was found to be perturbed in the presence of polyethylene glycol, however there was insignificant change in the secondary structure. It was observed that polyethylene glycol induces molten globule state in myoglobin, where the intermediate state holds hydrophobic patches and larger hydrodynamic volume as compared to the native protein. In addition, isothermal titration calorimetry (ITC) showed strong binding between myoglobin and polyethylene glycol, at the physiological pH. We hypothesize that polyethylene glycol induces molten globule conformation in myoglobin by interacting with heme group of myoglobin. We caution that the binding of protein with crowder and other soft interactions need to be gravely well thought-out when studying macromolecular crowding. In our case, destabilizing protein-crowder interactions could compete and overcome the stabilizing exclusion volume effect.
Collapse
Affiliation(s)
- Zahoor Ahmad Parray
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Sumra Shahid
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
| |
Collapse
|
24
|
Carter CW. Coding of Class I and II Aminoacyl-tRNA Synthetases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 966:103-148. [PMID: 28828732 PMCID: PMC5927602 DOI: 10.1007/5584_2017_93] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aminoacyl-tRNA synthetases and their cognate transfer RNAs translate the universal genetic code. The twenty canonical amino acids are sufficiently diverse to create a selective advantage for dividing amino acid activation between two distinct, apparently unrelated superfamilies of synthetases, Class I amino acids being generally larger and less polar, Class II amino acids smaller and more polar. Biochemical, bioinformatic, and protein engineering experiments support the hypothesis that the two Classes descended from opposite strands of the same ancestral gene. Parallel experimental deconstructions of Class I and II synthetases reveal parallel losses in catalytic proficiency at two novel modular levels-protozymes and Urzymes-associated with the evolution of catalytic activity. Bi-directional coding supports an important unification of the proteome; affords a genetic relatedness metric-middle base-pairing frequencies in sense/antisense alignments-that probes more deeply into the evolutionary history of translation than do single multiple sequence alignments; and has facilitated the analysis of hitherto unknown coding relationships in tRNA sequences. Reconstruction of native synthetases by modular thermodynamic cycles facilitated by domain engineering emphasizes the subtlety associated with achieving high specificity, shedding new light on allosteric relationships in contemporary synthetases. Synthetase Urzyme structural biology suggests that they are catalytically-active molten globules, broadening the potential manifold of polypeptide catalysts accessible to primitive genetic coding and motivating revisions of the origins of catalysis. Finally, bi-directional genetic coding of some of the oldest genes in the proteome places major limitations on the likelihood that any RNA World preceded the origins of coded proteins.
Collapse
Affiliation(s)
- Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7260, USA.
| |
Collapse
|
25
|
Bemporad F, Ramazzotti M. From the Evolution of Protein Sequences Able to Resist Self-Assembly to the Prediction of Aggregation Propensity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:1-47. [PMID: 28109326 DOI: 10.1016/bs.ircmb.2016.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Folding of polypeptide chains into biologically active entities is an astonishingly complex process, determined by the nature and the sequence of residues emerging from ribosomes. While it has been long believed that evolution has pressed genomes so that specific sequences could adopt unique, functional three-dimensional folds, it is now clear that complex protein machineries act as quality control system and supervise folding. Notwithstanding that, events such as erroneous folding, partial folding, or misfolding are frequent during the life of a cell or a whole organism, and they can escape controls. One of the possible outcomes of this misbehavior is cross-β aggregation, a super secondary structure which represents the hallmark of self-assembled, well organized, and extremely ordered structures termed amyloid fibrils. What if evolution would have not taken into account such possibilities? Twenty years of research point toward the idea that, in fact, evolution has constantly supervised the risk of errors and minimized their impact. In this review we tried to survey the major findings in the amyloid field, trying to describe what the real pitfalls of protein folding are-from an evolutionary perspective-and how sequence and structural features have evolved to balance the need for perfect, dynamic, functionally efficient structures, and the detrimental effects implicit in the dangerous process of folding. We will discuss how the knowledge obtained from these studies has been employed to produce computational methods able to assess, predict, and discriminate the aggregation properties of protein sequences.
Collapse
Affiliation(s)
- F Bemporad
- Università degli Studi di Firenze, Firenze, Italy.
| | - M Ramazzotti
- Università degli Studi di Firenze, Firenze, Italy.
| |
Collapse
|
26
|
Piazza M, Dieckmann T, Guillemette JG. Structural Studies of a Complex Between Endothelial Nitric Oxide Synthase and Calmodulin at Physiological Calcium Concentration. Biochemistry 2016; 55:5962-5971. [DOI: 10.1021/acs.biochem.6b00821] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Piazza
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Thorsten Dieckmann
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - J. Guy Guillemette
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| |
Collapse
|
27
|
Sapienza PJ, Li L, Williams T, Lee AL, Carter CW. An Ancestral Tryptophanyl-tRNA Synthetase Precursor Achieves High Catalytic Rate Enhancement without Ordered Ground-State Tertiary Structures. ACS Chem Biol 2016; 11:1661-8. [PMID: 27008438 PMCID: PMC5461432 DOI: 10.1021/acschembio.5b01011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Urzymes-short, active core modules derived from enzyme superfamilies-prepared from the two aminoacyl-tRNA synthetase (aaRS) classes contain only the modules shared by all related family members. They have been described as models for ancestral forms. Understanding them currently depends on inferences drawn from the crystal structures of the full-length enzymes. As aaRS Urzymes lack much of the mass of modern aaRS's, retaining only a small portion of the hydrophobic cores of the full-length enzymes, it is desirable to characterize their structures. We report preliminary characterization of (15)N tryptophanyl-tRNA synthetase Urzyme by heteronuclear single quantum coherence (HSQC) NMR spectroscopy supplemented by circular dichroism, thermal melting, and induced fluorescence of bound dye. The limited dispersion of (1)H chemical shifts (0.5 ppm) is inconsistent with a narrow ensemble of well-packed structures in either free or substrate-bound forms, although the number of resonances from the bound state increases, indicating a modest, ligand-dependent gain in structure. Circular dichroism spectroscopy shows the presence of helices and evidence of cold denaturation, and all ligation states induce Sypro Orange fluorescence at ambient temperatures. Although the term "molten globule" is difficult to define precisely, these characteristics are consistent with most such definitions. Active-site titration shows that a majority of molecules retain ∼60% of the transition state stabilization free energy observed in modern synthetases. In contrast to the conventional view that enzymes require stable tertiary structures, we conclude that a highly flexible ground-state ensemble can nevertheless bind tightly to the transition state for amino acid activation.
Collapse
Affiliation(s)
- Paul J. Sapienza
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy
| | - Li Li
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 25799
| | - Tishan Williams
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 25799
| | - Andrew L. Lee
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy
| | - Charles W. Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 25799
| |
Collapse
|
28
|
Characterisation of molten globule-like state of sheep serum albumin at physiological pH. Int J Biol Macromol 2016; 89:605-13. [PMID: 27180298 DOI: 10.1016/j.ijbiomac.2016.05.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/05/2016] [Accepted: 05/10/2016] [Indexed: 01/26/2023]
Abstract
Sheep serum albumin (SSA) is a 583 amino acid residues long multidomain monomeric protein which is rich in cysteine and low in tryptophan content. The serum albumins (from human, bovine and sheep) play a vital role among all proteins investigated until now, as they are the most copious circulatory proteins. We have purified SSA from sheep kidneys by a simple and efficient two-step purification procedure. Further, we have studied urea-induced denaturation of SSA by monitoring changes in the difference absorption coefficient at 287nm (Δε287), intrinsic fluorescence emission intensity at 347nm (F347) and mean residue ellipticity at 222nm ([θ]222) at pH 7.4 and 25°C. The coincidence of denaturation curves of these optical properties suggests that urea-induced denaturation is a bi-phasic process (native (N) state↔intermediate (X) state↔denatured (D) state) with a stable intermediate populated around 4.2-4.7M urea. The intermediate (X) state was further characterized by the far-UV and near-UV CD, dynamic light scattering (DLS) and fluorescence using 1-anilinonaphthalene-8-sulfonic acid (ANS) binding method. All denaturation curves were analyzed for Gibbs free energy changes associated with the equilibria, N state↔X state and X state↔D state in the absence of urea.
Collapse
|
29
|
Sajó R, Tőke O, Hajdú I, Jankovics H, Micsonai A, Dobó J, Kardos J, Vonderviszt F. Structural plasticity of the Salmonella FliS flagellar export chaperone. FEBS Lett 2016; 590:1103-13. [PMID: 27003324 DOI: 10.1002/1873-3468.12149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 11/11/2022]
Abstract
The Salmonella FliS flagellar export chaperone is a highly α-helical protein. Proteolytic experiments suggest that FliS has a compact core. However, the calorimetric melting profile of FliS does not show any melting transition in the 25-110 °C temperature range. Circular dichroism measurements reveal that FliS is losing its helical structure over a broad temperature range upon heating. These observations indicate that FliS unfolds in a noncooperative way and its native state shows features reminiscent of the molten globule state of proteins possessing substantial structural plasticity. As FliS has several binding partners within the cell, conformational adaptability seems to be an essential requirement to fulfill its multiple roles.
Collapse
Affiliation(s)
- Ráchel Sajó
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Orsolya Tőke
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - István Hajdú
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Hajnalka Jankovics
- Bio-Nanosystems Laboratory, Research Institute for Chemical and Process Engineering, University of Pannonia, Veszprém, Hungary
| | - András Micsonai
- MTA-ELTE NAP B Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - József Dobó
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - József Kardos
- MTA-ELTE NAP B Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Ferenc Vonderviszt
- Bio-Nanosystems Laboratory, Research Institute for Chemical and Process Engineering, University of Pannonia, Veszprém, Hungary.,Institute of Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary
| |
Collapse
|
30
|
Komarov PV, Khalatur PG, Khokhlov AR. A new concept for molecular engineering of artificial enzymes: a multiscale simulation. SOFT MATTER 2016; 12:689-704. [PMID: 26539842 DOI: 10.1039/c5sm02428e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We propose a new concept for the design of artificial enzymes from synthetic protein-like copolymers and non-natural functional monomers which in terms of their affinity for water can be divided into two categories: hydrophobic and hydrophilic. Hydrophilic monomers comprise catalytically active groups similar to those in the corresponding amino acid residues. A key ingredient of our approach is that the target globular conformation of protein-like, core-shell morphology with multiple catalytic groups appears spontaneously in the course of controlled radical polymerization in a selective solvent. As a proof of concept, we construct a fully synthetic analog of serine hydrolase, e.g.α-chymotrypsin, using the conformation-dependent sequence design approach and multiscale simulation that combines the methods of "mesoscale chemistry" and atomistic molecular dynamics (MD). A 100 ns GPU-accelerated MD simulation of the designed polymer-supported catalyst in the aqueous environment provides valuable information on the structural organization of this system that has been synthesized in our Lab.
Collapse
Affiliation(s)
- Pavel V Komarov
- Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russia
| | | | | |
Collapse
|
31
|
Gáspári Z, Nyitray L. Coiled coils as possible models of protein structure evolution. Biomol Concepts 2015; 2:199-210. [PMID: 25962029 DOI: 10.1515/bmc.2011.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 03/01/2011] [Indexed: 01/05/2023] Open
Abstract
Coiled coils are formed by two or more α-helices wrapped around one another. This structural motif often guides di-, tri- or multimerization of proteins involved in diverse biological processes such as membrane fusion, signal transduction and the organization of the cytoskeleton. Although coiled coil motifs seem conceptually simple and their existence was proposed in the early 1950s, the high variability of the motif makes coiled coil prediction from sequence a difficult task. They might be confused with intrinsically disordered sequences and even more with a recently described structural motif, the charged single α-helix. By contrast, the versatility of coiled coil structures renders them an ideal candidate for protein (re)design and many novel variants have been successfully created to date. In this paper, we review coiled coils in the light of protein evolution by putting our present understanding of the motif and its variants in the context of structural interconversions. We argue that coiled coils are ideal subjects for studies of subtle and large-scale structural changes because of their well-characterized and versatile nature.
Collapse
|
32
|
Biophysical Methods to Investigate Intrinsically Disordered Proteins: Avoiding an “Elephant and Blind Men” Situation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 870:215-60. [DOI: 10.1007/978-3-319-20164-1_7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
33
|
Martinez-Rodriguez L, Erdogan O, Jimenez-Rodriguez M, Gonzalez-Rivera K, Williams T, Li L, Weinreb V, Collier M, Chandrasekaran SN, Ambroggio X, Kuhlman B, Carter CW. Functional Class I and II Amino Acid-activating Enzymes Can Be Coded by Opposite Strands of the Same Gene. J Biol Chem 2015; 290:19710-25. [PMID: 26088142 DOI: 10.1074/jbc.m115.642876] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 01/11/2023] Open
Abstract
Aminoacyl-tRNA synthetases (aaRS) catalyze both chemical steps that translate the universal genetic code. Rodin and Ohno offered an explanation for the existence of two aaRS classes, observing that codons for the most highly conserved Class I active-site residues are anticodons for corresponding Class II active-site residues. They proposed that the two classes arose simultaneously, by translation of opposite strands from the same gene. We have characterized wild-type 46-residue peptides containing ATP-binding sites of Class I and II synthetases and those coded by a gene designed by Rosetta to encode the corresponding peptides on opposite strands. Catalysis by WT and designed peptides is saturable, and the designed peptides are sensitive to active-site residue mutation. All have comparable apparent second-order rate constants 2.9-7.0E-3 M(-1) s(-1) or ∼750,000-1,300,000 times the uncatalyzed rate. The activities of the two complementary peptides demonstrate that the unique information in a gene can have two functional interpretations, one from each complementary strand. The peptides contain phylogenetic signatures of longer, more sophisticated catalysts we call Urzymes and are short enough to bridge the gap between them and simpler uncoded peptides. Thus, they directly substantiate the sense/antisense coding ancestry of Class I and II aaRS. Furthermore, designed 46-mers achieve similar catalytic proficiency to wild-type 46-mers by significant increases in both kcat and Km values, supporting suggestions that the earliest peptide catalysts activated ATP for biosynthetic purposes.
Collapse
Affiliation(s)
- Luis Martinez-Rodriguez
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Ozgün Erdogan
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Mariel Jimenez-Rodriguez
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Katiria Gonzalez-Rivera
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Tishan Williams
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Li Li
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Violetta Weinreb
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Martha Collier
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Srinivas Niranj Chandrasekaran
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Xavier Ambroggio
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Brian Kuhlman
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| | - Charles W Carter
- From the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260
| |
Collapse
|
34
|
Piazza M, Guillemette JG, Dieckmann T. Dynamics of nitric oxide synthase-calmodulin interactions at physiological calcium concentrations. Biochemistry 2015; 54:1989-2000. [PMID: 25751535 DOI: 10.1021/bi501353s] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The intracellular Ca²⁺ concentration is an important regulator of many cellular functions. The small acidic protein calmodulin (CaM) serves as a Ca²⁺ sensor and control element for many enzymes. Nitric oxide synthase (NOS) is one of the proteins that is activated by CaM and plays a major role in a number of key physiological and pathological processes. Previous studies have shown CaM to act like a switch that causes a conformational change in NOS to allow for the electron transfer between the reductase and oxygenase domains through a process that is thought to be highly dynamic. We have analyzed the structure and dynamics of complexes formed by peptides based on inducible NOS (iNOS) and endothelial NOS (eNOS) with CaM at Ca²⁺ concentrations that mimic the physiological basal (17 and 100 nM) and elevated levels (225 nM) found in mammalian cells using fluorescence techniques and nuclear magnetic resonance spectroscopy. The results show the CaM-NOS complexes have similar structures at physiological and fully saturated Ca²⁺ levels; however, their dynamics are remarkably different. At 225 nM Ca²⁺, the CaM-NOS complexes show overall an increase in backbone dynamics, when compared to the dynamics of the complexes at saturating Ca²⁺ concentrations. Specifically, the N-lobe of CaM in the CaM-iNOS complex displays a lower internal mobility (higher S²) and higher exchange protection compared to those of the CaM-eNOS complex. In contrast, the C-lobe of CaM in the CaM-eNOS complex is less dynamic. These results illustrate that structures of CaM-NOS complexes determined at saturated Ca²⁺ concentrations cannot provide a complete picture because the differences in intramolecular dynamics become visible only at physiological Ca²⁺ levels.
Collapse
Affiliation(s)
- Michael Piazza
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - J Guy Guillemette
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Thorsten Dieckmann
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| |
Collapse
|
35
|
Panigrahi K, Applegate GA, Malik G, Berkowitz DB. Combining a Clostridial enzyme exhibiting unusual active site plasticity with a remarkably facile sigmatropic rearrangement: rapid, stereocontrolled entry into densely functionalized fluorinated phosphonates for chemical biology. J Am Chem Soc 2015; 137:3600-9. [PMID: 25719907 DOI: 10.1021/jacs.5b00022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Described is an efficient stereocontrolled route into valuable, densely functionalized fluorinated phosphonates that takes advantage of (i) a Clostridial enzyme to set the absolute stereochemistry and (ii) a new [3,3]-sigmatropic rearrangement of the thiono-Claisen variety that is among the fastest sigmatropic rearrangements yet reported. Here, a pronounced rate enhancement is achieved by distal fluorination. This rearrangement is completely stereoretentive, parlaying the enzymatically established β-C-O stereochemistry in the substrate into the δ-C-S stereochemistry in the product. The final products are of interest to chemical biology, with a platform for Zn-aminopeptidase A inhibitors being constructed here. The enzyme, Clostridium acetobutylicum (CaADH), recently expressed by our group, reduces a spectrum of γ,δ-unsaturated β-keto-α,α-difluorophosphonate esters (93-99% ee; 10 examples). The resultant β-hydroxy-α,α-difluorophosphonates possess the "L"-stereochemistry, opposite to that previously observed for the CaADH-reduction of ω-keto carboxylate esters ("D"), indicating an unusual active site plasticity. For the thiono-Claisen rearrangement, a notable structure-reactivity relationship is observed. Measured rate constants vary by over 3 orders of magnitude, depending upon thiono-ester structure. Temperature-dependent kinetics reveal an unusually favorable entropy of activation (ΔS(‡) = 14.5 ± 0.6 e.u.). Most notably, a 400-fold rate enhancement is seen upon fluorination of the distal arene ring, arising from favorable enthalpic (ΔΔH(‡) = -2.3 kcal/mol) and entropic (ΔΔS(‡) = 4 e.u., i.e. 1.2 kcal/mol at rt) contributions. The unusual active site plasticity seen here is expected to drive structural biology studies on CaADH, while the exceptionally facile sigmatropic rearrangement is expected to drive computational studies to elucidate its underlying entropic and enthalpic basis.
Collapse
Affiliation(s)
- Kaushik Panigrahi
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Gregory A Applegate
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Guillaume Malik
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - David B Berkowitz
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| |
Collapse
|
36
|
Schulenburg C, Stark Y, Künzle M, Hilvert D. Comparative laboratory evolution of ordered and disordered enzymes. J Biol Chem 2015; 290:9310-20. [PMID: 25697360 DOI: 10.1074/jbc.m115.638080] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Indexed: 11/06/2022] Open
Abstract
Intrinsically disordered proteins are ubiquitous in nature. To assess potential evolutionary advantages and disadvantages of structural disorder under controlled laboratory conditions, we directly compared the evolvability of weakly active ordered and disordered variants of dihydrofolate reductase by genetic selection. The circularly permuted Escherichia coli enzyme, which exists as a molten globule in the absence of ligands, and a well folded deletion mutant of the Bacillus stearothermophilus enzyme served as starting points. Both scaffolds evolved at similar rates and to similar extents, reaching near-native activity after three rounds of mutagenesis and selection. Surprisingly, however, the starting structural properties of the two scaffolds changed only marginally during optimization. Although the ordered and disordered proteins accumulated distinct sets of mutations, the changes introduced likely improved catalytic efficiency indirectly in both cases by bolstering the network of dynamic conformational fluctuations that productively couple into the reaction coordinate.
Collapse
Affiliation(s)
- Cindy Schulenburg
- From the Laboratory of Organic Chemistry, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - Yvonne Stark
- From the Laboratory of Organic Chemistry, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - Matthias Künzle
- From the Laboratory of Organic Chemistry, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - Donald Hilvert
- From the Laboratory of Organic Chemistry, Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| |
Collapse
|
37
|
Abstract
![]()
Biological activities of enzymes, including
regulation or coordination of mechanistic stages preceding or following
the chemical step, may depend upon kinetic or equilibrium changes
in protein conformations. Exchange of more open or flexible conformational
states with more closed or constrained states can influence inhibition,
allosteric regulation, substrate recognition, formation of the Michaelis
complex, side reactions, and product release. NMR spectroscopy has
long been applied to the study of conformational dynamic processes
in enzymes because these phenomena can be characterized over multiple
time scales with atomic site resolution. Laboratory-frame spin-relaxation
measurements, sensitive to reorientational motions on picosecond–nanosecond
time scales, and rotating-frame relaxation-dispersion measurements,
sensitive to chemical exchange processes on microsecond–millisecond
time scales, provide information on both conformational distributions
and kinetics. This Account reviews NMR spin relaxation studies of
the enzymes ribonuclease HI from mesophilic (Escherichia coli) and thermophilic (Thermus thermophilus) bacteria, E. coli AlkB, and Saccharomyces cerevisiae triosephosphate isomerase to illustrate the contributions of conformational
flexibility and dynamics to diverse steps in enzyme mechanism. Spin relaxation measurements and molecular dynamics (MD) simulations
of the bacterial ribonuclease H enzymes show that the handle region,
one of three loop regions that interact with substrates, interconverts
between two conformations. Comparison of these conformations with
the structure of the complex between Homo sapiens ribonuclease H and a DNA:RNA substrate suggests that the more closed
state is inhibitory to binding. The large population of the closed
conformation in T. thermophilus ribonuclease H contributes
to the increased Michaelis constant compared with the E. coli enzyme. NMR spin relaxation and fluorescence spectroscopy have characterized
a conformational transition in AlkB between an open state, in which
the side chains of methionine residues in the active site are disordered,
and a closed state, in which these residues are ordered. The open
state is highly populated in the AlkB/Zn(II) complex, and the closed
state is highly populated in the AlkB/Zn(II)/2OG/substrate complex,
in which 2OG is the 2-oxoglutarate cosubstrate and the substrate is
a methylated DNA oligonucleotide. The equilibrium is shifted to approximately
equal populations of the two conformations in the AlkB/Zn(II)/2OG
complex. The conformational shift induced by 2OG ensures that 2OG
binds to AlkB/Zn(II) prior to the substrate. In addition, the opening
rate of the closed conformation limits premature release of substrate,
preventing generation of toxic side products by reaction with water.
Closure of active site loop 6 in triosephosphate isomerase is critical
for forming the Michaelis complex, but reopening of the loop after
the reaction is (partially) rate limiting. NMR spin relaxation and
MD simulations of triosephosphate isomerase in complex with glycerol
3-phosphate demonstrate that closure of loop 6 is a highly correlated
rigid-body motion. The MD simulations also indicate that motions of
Gly173 in the most flexible region of loop 6 contribute to opening
of the active site loop for product release. Considered together,
these three enzyme systems illustrate the power of NMR spin relaxation
investigations in providing global insights into the role of conformational
dynamic processes in the mechanisms of enzymes from initial activation
to final product release.
Collapse
Affiliation(s)
- Arthur G. Palmer
- Department of Biochemistry and
Molecular Biophysics, Columbia University, 701 West 168th Street, New York, New York 10032, United States
| |
Collapse
|
38
|
Haque MA, Ubaid-ullah S, Zaidi S, Hassan MI, Islam A, Batra JK, Ahmad F. Characterization of pre-molten globule state of yeast iso-1-cytochrome c and its deletants at pH 6.0 and 25 °C. Int J Biol Macromol 2015; 72:1406-18. [DOI: 10.1016/j.ijbiomac.2014.10.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 10/21/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
|
39
|
Electrostatic transition state stabilization rather than reactant destabilization provides the chemical basis for efficient chorismate mutase catalysis. Proc Natl Acad Sci U S A 2014; 111:17516-21. [PMID: 25422475 DOI: 10.1073/pnas.1408512111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
For more than half a century, transition state theory has provided a useful framework for understanding the origins of enzyme catalysis. As proposed by Pauling, enzymes accelerate chemical reactions by binding transition states tighter than substrates, thereby lowering the activation energy compared with that of the corresponding uncatalyzed process. This paradigm has been challenged for chorismate mutase (CM), a well-characterized metabolic enzyme that catalyzes the rearrangement of chorismate to prephenate. Calculations have predicted the decisive factor in CM catalysis to be ground state destabilization rather than transition state stabilization. Using X-ray crystallography, we show, in contrast, that a sluggish variant of Bacillus subtilis CM, in which a cationic active-site arginine was replaced by a neutral citrulline, is a poor catalyst even though it effectively preorganizes chorismate for the reaction. A series of high-resolution molecular snapshots of the reaction coordinate, including the apo enzyme, and complexes with substrate, transition state analog and product, demonstrate that an active site, which is only complementary in shape to a reactive substrate conformer, is insufficient for effective catalysis. Instead, as with other enzymes, electrostatic stabilization of the CM transition state appears to be crucial for achieving high reaction rates.
Collapse
|
40
|
Le P, Zhao J, Franzen S. Correlation of Heme Binding Affinity and Enzyme Kinetics of Dehaloperoxidase. Biochemistry 2014; 53:6863-77. [DOI: 10.1021/bi5005975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Le
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| |
Collapse
|
41
|
Abstract
Biomolecules are the prime information processing elements of living matter. Most of these inanimate systems are polymers that compute their own structures and dynamics using as input seemingly random character strings of their sequence, following which they coalesce and perform integrated cellular functions. In large computational systems with finite interaction-codes, the appearance of conflicting goals is inevitable. Simple conflicting forces can lead to quite complex structures and behaviors, leading to the concept of frustration in condensed matter. We present here some basic ideas about frustration in biomolecules and how the frustration concept leads to a better appreciation of many aspects of the architecture of biomolecules, and especially how biomolecular structure connects to function by means of localized frustration. These ideas are simultaneously both seductively simple and perilously subtle to grasp completely. The energy landscape theory of protein folding provides a framework for quantifying frustration in large systems and has been implemented at many levels of description. We first review the notion of frustration from the areas of abstract logic and its uses in simple condensed matter systems. We discuss then how the frustration concept applies specifically to heteropolymers, testing folding landscape theory in computer simulations of protein models and in experimentally accessible systems. Studying the aspects of frustration averaged over many proteins provides ways to infer energy functions useful for reliable structure prediction. We discuss how frustration affects folding mechanisms. We review here how the biological functions of proteins are related to subtle local physical frustration effects and how frustration influences the appearance of metastable states, the nature of binding processes, catalysis and allosteric transitions. In this review, we also emphasize that frustration, far from being always a bad thing, is an essential feature of biomolecules that allows dynamics to be harnessed for function. In this way, we hope to illustrate how Frustration is a fundamental concept in molecular biology.
Collapse
|
42
|
Carter CW. Urzymology: experimental access to a key transition in the appearance of enzymes. J Biol Chem 2014; 289:30213-30220. [PMID: 25210034 DOI: 10.1074/jbc.r114.567495] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Urzymes are catalysts derived from invariant cores of protein superfamilies. Urzymes from both aminoacyl-tRNA synthetase classes possess sophisticated catalytic mechanisms: pre-steady state bursts, significant transition-state stabilization of both amino acid activation, and tRNA acylation. However, they have insufficient specificity to ensure a fully developed genetic code, suggesting that they participated in synthesizing statistical proteins. They represent a robust experimental platform from which to articulate and test hypotheses both about their own ancestors and about how they, in turn, evolved into modern enzymes. They help reshape numerous paradigms from the RNA World hypothesis to protein structure databases and allostery.
Collapse
Affiliation(s)
- Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260.
| |
Collapse
|
43
|
Liebherr RB, Renner M, Gorris HH. A single molecule perspective on the functional diversity of in vitro evolved β-glucuronidase. J Am Chem Soc 2014; 136:5949-55. [PMID: 24684619 DOI: 10.1021/ja412379p] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanisms that drive the evolution of new enzyme activity have been investigated by comparing the kinetics of wild-type and in vitro evolved β-glucuronidase (GUS) at the single molecule level. Several hundred single GUS molecules were separated in large arrays of 62,500 ultrasmall reaction chambers etched into the surface of a fused silica slide to observe their individual substrate turnover rates in parallel by fluorescence microscopy. Individual GUS molecules feature long-lived but divergent activity states, and their mean activity is consistent with classic Michaelis-Menten kinetics. The large number of single molecule substrate turnover rates is representative of the activity distribution within an entire enzyme population. Partially evolved GUS displays a much broader activity distribution among individual enzyme molecules than wild-type GUS. The broader activity distribution indicates a functional division of work between individual molecules in a population of partially evolved enzymes that-as so-called generalists-are characterized by their promiscuous activity with many different substrates.
Collapse
Affiliation(s)
- Raphaela B Liebherr
- Institute of Analytical Chemistry, Chemo- and Biosensors and ‡Institute of Biophysics and Physical Biochemistry, University of Regensburg , 93040 Regensburg, Germany
| | | | | |
Collapse
|
44
|
Walczak MJ, Samatanga B, van Drogen F, Peter M, Jelesarov I, Wider G. The RING Domain of the Scaffold Protein Ste5 Adopts a Molten Globular Character with High Thermal and Chemical Stability. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201306702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
45
|
Walczak MJ, Samatanga B, van Drogen F, Peter M, Jelesarov I, Wider G. The RING domain of the scaffold protein Ste5 adopts a molten globular character with high thermal and chemical stability. Angew Chem Int Ed Engl 2013; 53:1320-3. [PMID: 24356903 DOI: 10.1002/anie.201306702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/20/2013] [Indexed: 11/06/2022]
Abstract
Ste5 is a scaffold protein that controls the pheromone response of the MAP-kinase cascade in yeast cells. Upon pheromone stimulation, Ste5 (through its RING-H2 domain) interacts with the β and γ subunits of an activated heterodimeric G protein and promotes activation of the MAP-kinase cascade. With structural and biophysical studies, we show that the Ste5 RING-H2 domain exists as a molten globule under native buffer conditions, in yeast extracts, and even in denaturing conditions containing urea (7 M). Furthermore, it exhibits high thermal stability in native conditions. Binding of the Ste5 RING-H2 domain to the physiological Gβ/γ (Ste4/Ste18) ligand is accompanied by a conformational transition into a better folded, more globular structure. This study reveals novel insights into the folding mechanism and recruitment of binding partners by the Ste5 RING-H2 domain. We speculate that many RING domains may share a similar mechanism of substrate recognition and molten-globule-like character.
Collapse
Affiliation(s)
- Michal J Walczak
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093 Zürich (Switzerland)
| | | | | | | | | | | |
Collapse
|
46
|
Wild-type and molten globular chorismate mutase achieve comparable catalytic rates using very different enthalpy/entropy compensations. Sci China Chem 2013. [DOI: 10.1007/s11426-013-5021-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
47
|
Li J, Ding S, Cowan JA. Thermodynamic and structural analysis of human NFU conformational chemistry. Biochemistry 2013; 52:4904-13. [PMID: 23796308 DOI: 10.1021/bi400320s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human NFU has been implicated in the formation of inorganic sulfide required for cellular iron-sulfur cluster biosynthesis. The protein contains a well-structured N-terminal domain and a C-terminal domain with molten globule characteristics that also contains a thioredoxin-like pair of redox active Cys residues that promote persulfide reductase activity. Recent reports have highlighted the existence of structural flexibility in the ISU/IscU-type scaffold proteins that mediate Fe-S cluster assembly, which is also likely to serve an important role in the pathway to Fe-S cluster maturation. We have previously reported similar structural mobility for the C-terminal domain of human NFU, a protein that has been implicated in the production of sulfide for cluster synthesis, while homologous proteins have also been suggested to serve as Fe-S cluster carriers. Herein we quantitatively characterize the structural stability of the two domains of human NFU and in particular the functional C-terminal domain. The results of differential scanning calorimetry and variable temperature circular dichroism (VTCD) studies have been used to analyze the temperature-dependent structural melting profiles of the N- and C-terminal domains, relative to both full-length NFU and an equimolar ratio of the N- and C-terminal domains, and correlated with structural information derived from NMR data. Calorimetry results indicate that the C-terminal NFU domain undergoes a significant structural stabilization following interaction with the N-terminal domain, which resulted in a novel and distinctive transition melting profile (Tm(sec) = 58.1 ± 0.4 °C, ΔHv(sec) = 60.4 ± 5.3 kcal/mol, Tm(ter) = 49.3 ± 0.3 °C, ΔHv(ter) = 71.8 ± 5.8 kcal/mol). VTCD experiments also revealed a secondary structure transition at 59.2 °C in agreement with calorimetry results. The degree of stabilization was found to be more significant in the full-length NFU, as the C-terminal domain transitions were recorded at higher temperatures (Tm(sec) = 63.3 ± 3.4 °C, ΔHv(sec) = 41.8 ± 8.2 kcal/mol). The interactions between the two domains demonstrated the hallmarks of a hydrophobic character, as increased ionic strength decreased the degree of stabilization of the C-terminal domain. An increase of 2% in α-helix content further supports interaction between the two domains, leading to greater secondary structure stabilization. Heteronuclear single-quantum coherence experiments indicate that the C-terminal domain adopts an alternate tertiary conformation following binding to the N-terminal domain. The structural rigidity of the N-terminal domain leads to an alternative conformation of the C-terminal domain, suggesting that such an interaction, although weaker than that of the covalently attached native NFU, is important for the structural chemistry of the native full-length protein. The results also emphasize the likely general importance of such structural flexibility in select proteins mediating metal cofactor biosynthesis.
Collapse
Affiliation(s)
- Jingwei Li
- Evans Laboratory of Chemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | | | | |
Collapse
|
48
|
Conformational dynamics control ubiquitin-deubiquitinase interactions and influence in vivo signaling. Proc Natl Acad Sci U S A 2013; 110:11379-84. [PMID: 23801757 DOI: 10.1073/pnas.1302407110] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Ubiquitin is a highly conserved eukaryotic protein that interacts with a diverse set of partners to act as a cellular signaling hub. Ubiquitin's conformational flexibility has been postulated to underlie its multifaceted recognition. Here we use computational and library-based means to interrogate core mutations that modulate the conformational dynamics of human ubiquitin. These ubiquitin variants exhibit increased affinity for the USP14 deubiquitinase, with concomitantly reduced affinity for other deubiquitinases. Strikingly, the kinetics of conformational motion are dramatically slowed in these variants without a detectable change in either the ground state fold or excited state population. These variants can be ligated into substrate-linked chains in vitro and in vivo but cannot solely support growth in eukaryotic cells. Proteomic analyses reveal nearly identical interaction profiles between WT ubiquitin and the variants but identify a small subset of altered interactions. Taken together, these results show that conformational dynamics are critical for ubiquitin-deubiquitinase interactions and imply that the fine tuning of motion has played a key role in the evolution of ubiquitin as a signaling hub.
Collapse
|
49
|
Uversky VN. A decade and a half of protein intrinsic disorder: biology still waits for physics. Protein Sci 2013; 22:693-724. [PMID: 23553817 PMCID: PMC3690711 DOI: 10.1002/pro.2261] [Citation(s) in RCA: 364] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 03/23/2013] [Accepted: 03/25/2013] [Indexed: 12/28/2022]
Abstract
The abundant existence of proteins and regions that possess specific functions without being uniquely folded into unique 3D structures has become accepted by a significant number of protein scientists. Sequences of these intrinsically disordered proteins (IDPs) and IDP regions (IDPRs) are characterized by a number of specific features, such as low overall hydrophobicity and high net charge which makes these proteins predictable. IDPs/IDPRs possess large hydrodynamic volumes, low contents of ordered secondary structure, and are characterized by high structural heterogeneity. They are very flexible, but some may undergo disorder to order transitions in the presence of natural ligands. The degree of these structural rearrangements varies over a very wide range. IDPs/IDPRs are tightly controlled under the normal conditions and have numerous specific functions that complement functions of ordered proteins and domains. When lacking proper control, they have multiple roles in pathogenesis of various human diseases. Gaining structural and functional information about these proteins is a challenge, since they do not typically "freeze" while their "pictures are taken." However, despite or perhaps because of the experimental challenges, these fuzzy objects with fuzzy structures and fuzzy functions are among the most interesting targets for modern protein research. This review briefly summarizes some of the recent advances in this exciting field and considers some of the basic lessons learned from the analysis of physics, chemistry, and biology of IDPs.
Collapse
Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA.
| |
Collapse
|
50
|
Honaker MT, Acchione M, Zhang W, Mannervik B, Atkins WM. Enzymatic detoxication, conformational selection, and the role of molten globule active sites. J Biol Chem 2013; 288:18599-611. [PMID: 23649628 DOI: 10.1074/jbc.m112.445767] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The role of conformational ensembles in enzymatic reactions remains unclear. Discussion concerning "induced fit" versus "conformational selection" has, however, ignored detoxication enzymes, which exhibit catalytic promiscuity. These enzymes dominate drug metabolism and determine drug-drug interactions. The detoxication enzyme glutathione transferase A1-1 (GSTA1-1), exploits a molten globule-like active site to achieve remarkable catalytic promiscuity wherein the substrate-free conformational ensemble is broad with barrierless transitions between states. A quantitative index of catalytic promiscuity is used to compare engineered variants of GSTA1-1 and the catalytic promiscuity correlates strongly with characteristics of the thermodynamic partition function, for the substrate-free enzymes. Access to chemically disparate transition states is encoded by the substrate-free conformational ensemble. Pre-steady state catalytic data confirm an extension of the conformational selection model, wherein different substrates select different starting conformations. The kinetic liability of the conformational breadth is minimized by a smooth landscape. We propose that "local" molten globule behavior optimizes detoxication enzymes.
Collapse
Affiliation(s)
- Matthew T Honaker
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610, USA
| | | | | | | | | |
Collapse
|