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Satheesh S, Al Solami L. Antifouling activities of proteinase K and α-amylase enzymes: Laboratory bioassays and in silico analysis. Heliyon 2024; 10:e31683. [PMID: 38828329 PMCID: PMC11140711 DOI: 10.1016/j.heliyon.2024.e31683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/02/2024] [Accepted: 05/20/2024] [Indexed: 06/05/2024] Open
Abstract
The application of enzymes as antifoulants is one of the environment-friendly strategies in biofouling management. In this study, antifouling activities of commercially available proteinase K and α-amylase enzymes were evaluated using barnacle larva and biofilm-forming bacteria as test organisms. The enzymes were also tested against barnacle cement protein through in silico analysis. The results showed that both enzymes inhibited the attachment of bacteria and settlement of barnacle larvae on the test surface. The lowest minimum inhibitory concentration of 0.312 mg ml-1 was exhibited by proteinase K against biofilm-forming bacteria. The calculated LC50 values for proteinase K and α-amylase against the barnacle nauplii were 91.8 and 230.96 mg ml-1 respectively. While α-amylase showed higher antibiofilm activity, proteinase K exhibited higher anti-larval settlement activity. Similarly, in silico analysis of the enzymes revealed promising anti-settlement activity, as the enzymes showed good binding scores with barnacle cement protein. Overall, the results suggested that the enzymes proteinase K and α-amylase could be used in antifouling coatings to reduce the settlement of biofouling on artificial materials in the marine environment.
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Affiliation(s)
- Sathianeson Satheesh
- Department of Marine Biology, Faculty of Marine Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Lafi Al Solami
- Department of Marine Biology, Faculty of Marine Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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2
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Davoodi S, Daryaee F, Iuliano JN, Collado JT, He Y, Pollard AC, Gil AA, Aramini JM, Tonge PJ. Evaluating the Impact of the Tyr158 p Ka on the Mechanism and Inhibition of InhA, the Enoyl-ACP Reductase from Mycobacterium tuberculosis. Biochemistry 2023; 62:1943-1952. [PMID: 37270808 PMCID: PMC10329767 DOI: 10.1021/acs.biochem.2c00606] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
InhA, the Mycobacterium tuberculosis enoyl-ACP reductase, is a target for the tuberculosis (TB) drug isoniazid (INH). InhA inhibitors that do not require KatG activation avoid the most common mechanism of INH resistance, and there are continuing efforts to fully elucidate the enzyme mechanism to drive inhibitor discovery. InhA is a member of the short-chain dehydrogenase/reductase superfamily characterized by a conserved active site Tyr, Y158 in InhA. To explore the role of Y158 in the InhA mechanism, this residue has been replaced by fluoroTyr residues that increase the acidity of Y158 up to ∼3200-fold. Replacement of Y158 with 3-fluoroTyr (3-FY) and 3,5-difluoroTyr (3,5-F2Y) has no effect on kcatapp/KMapp nor on the binding of inhibitors to the open form of the enzyme (Kiapp), whereas both kcatapp/KMapp and Kiapp are altered by seven-fold for the 2,3,5-trifluoroTyr variant (2,3,5-F3Y158 InhA). 19F NMR spectroscopy suggests that 2,3,5-F3Y158 is ionized at neutral pH indicating that neither the acidity nor ionization state of residue 158 has a major impact on catalysis or on the binding of substrate-like inhibitors. In contrast, Ki*app is decreased 6- and 35-fold for the binding of the slow-onset inhibitor PT504 to 3,5-F2Y158 and 2,3,5-F3Y158 InhA, respectively, indicating that Y158 stabilizes the closed form of the enzyme adopted by EI*. The residence time of PT504 is reduced ∼four-fold for 2,3,5-F3Y158 InhA compared to wild-type, and thus, the hydrogen bonding interaction of the inhibitor with Y158 is an important factor in the design of InhA inhibitors with increased residence times on the enzyme.
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Affiliation(s)
- Shabnam Davoodi
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Fereidoon Daryaee
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - James N. Iuliano
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Jinnette Tolentino Collado
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Yongle He
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Alyssa C. Pollard
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - Agnieszka A. Gil
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
| | - James M. Aramini
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, United States
| | - Peter J. Tonge
- Center for Advanced Study of Drug Action, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Chemistry, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
- Department of Radiology, John S. Toll Drive, Stony Brook University, Stony Brook, NY 11794-3400, United States
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3
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Fresch E, Collini E. The Role of H-Bonds in the Excited-State Properties of Multichromophoric Systems: Static and Dynamic Aspects. Molecules 2023; 28:molecules28083553. [PMID: 37110786 PMCID: PMC10141795 DOI: 10.3390/molecules28083553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/12/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023] Open
Abstract
Given their importance, hydrogen bonds (H-bonds) have been the subject of intense investigation since their discovery. Indeed, H-bonds play a fundamental role in determining the structure, the electronic properties, and the dynamics of complex systems, including biologically relevant materials such as DNA and proteins. While H-bonds have been largely investigated for systems in their electronic ground state, fewer studies have focused on how the presence of H-bonds could affect the static and dynamic properties of electronic excited states. This review presents an overview of the more relevant progress in studying the role of H-bond interactions in modulating excited-state features in multichromophoric biomimetic complex systems. The most promising spectroscopic techniques that can be used for investigating the H-bond effects in excited states and for characterizing the ultrafast processes associated with their dynamics are briefly summarized. Then, experimental insights into the modulation of the electronic properties resulting from the presence of H-bond interactions are provided, and the role of the H-bond in tuning the excited-state dynamics and the related photophysical processes is discussed.
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Affiliation(s)
- Elisa Fresch
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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4
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Pal P, Chakraborty S, Jana B. Number of Hydrogen Bonds per Unit Solvent Accessible Surface Area: A Descriptor of Functional States of Proteins. J Phys Chem B 2022; 126:10822-10833. [PMID: 36524238 DOI: 10.1021/acs.jpcb.2c05367] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Proteins function close to native and near-native conformations. These states are evolutionarily selected to ensure the effect of mutations is minimized. The structural organization of a protein is hierarchical and modular, which reduces the dimensionality of the configurational space of the native states. Thus, finding appropriate descriptors that define the native state among all possible states of a protein is a problem of immense interest. The present study explores the correlation between solvent accessible surface areas (SASAs) and different intraprotein as well as protein-water hydrogen bonds of 55 single-chain globular proteins from four different structural classes (all α, all β, α+β, and α/β), 16 multichain proteins, and 4 macromolecular complexes. A systematic analysis of the solvent accessible surface area and intraprotein and protein-water hydrogen bonds suggests a linear relationship between SASAs and hydrogen bonds. The number of protein-water hydrogen bonds per unit SASA ranges from 3 to 4 for all the different structural protein classes. In contrast, the number of intramolecular hydrogen bonds per unit SASA, including the mainchain-mainchain, mainchain-sidechain, and sidechain-sidechain, varies between 0.75 to 2. The solvation free energy of a protein linearly decreases with SASA. Our study also shows that the solvation free energy/SASA varies from -75 to -105 kJ mol-1 nm-2 across all the native states studied here. The number conservancy of intraprotein hydrogen bonds per unit SASA possibly imparts structural stability to the native structure. On the other hand, 3-4 protein-water hydrogen bonds per unit SASA are possibly required to maintain a balance between the solubility and functionality of the native states. This study provides a basis for synthetic biologists to design new folds with improved functionality.
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Affiliation(s)
- Prasun Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sandipan Chakraborty
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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5
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Ghanbari Moheb Seraj R, Tohidfar M, Azimzadeh Irani M, Esmaeilzadeh-Salestani K, Moradian T, Ahmadikhah A, Behnamian M. Metabolomics analysis of milk thistle lipids to identify drought-tolerant genes. Sci Rep 2022; 12:12827. [PMID: 35896570 PMCID: PMC9329356 DOI: 10.1038/s41598-022-16887-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 07/18/2022] [Indexed: 11/09/2022] Open
Abstract
Milk thistle is an oil and medicinal crop known as an alternative oil crop with a high level of unsaturated fatty acids, which makes it a favorable edible oil for use in food production. To evaluate the importance of Milk thistle lipids in drought tolerance, an experiment was performed in field conditions under three different water deficit levels (Field capacity (FC), 70% FC and 40% FC). After harvesting seeds of the plant, their oily and methanolic extracts were isolated, and subsequently, types and amounts of lipids were measured using GC-MS. Genes and enzymes engaged in biosynthesizing of these lipids were identified and their expression in Arabidopsis was investigated under similar conditions. The results showed that content of almost all measured lipids of milk thistle decreased under severe drought stress, but genes (belonged to Arabidopsis), which were involved in their biosynthetic pathway showed different expression patterns. Genes biosynthesizing lipids, which had significant amounts were selected and their gene and metabolic network were established. Two networks were correlated, and for each pathway, their lipids and respective biosynthesizing genes were grouped together. Four up-regulated genes including PXG3, LOX2, CYP710A1, PAL and 4 down-regulated genes including FATA2, CYP86A1, LACS3, PLA2-ALPHA were selected. The expression of these eight genes in milk thistle was similar to Arabidopsis under drought stress. Thus, PXG3, PAL, LOX2 and CYP86A1 genes that increased expression were selected for protein analysis. Due to the lack of protein structure of these genes in the milk thistle, modeling homology was performed for them. The results of molecular docking showed that the four proteins CYP86A1, LOX2, PAL and PXG3 bind to ligands HEM, 11O, ACT and LIG, respectively. HEM ligand was involved in production of secondary metabolites and dehydration tolerance, and HEM binding site remained conserved in various plants. CA ligands were involved in synthesis of cuticles and waxes. Overall, this study confirmed the importance of lipids in drought stress tolerance in milk thistle.
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Affiliation(s)
- Rahele Ghanbari Moheb Seraj
- Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Masoud Tohidfar
- Department of Plant Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | | | - Keyvan Esmaeilzadeh-Salestani
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Fr. R. Kreutzwaldi 1, 51014, Tartu, Estonia
| | - Toktam Moradian
- Department of Horticultural Sciences, Islamic Azad University, Shirvan Branch, Shirvan, Iran
| | - Asadollah Ahmadikhah
- Department of Plant Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Mahdi Behnamian
- Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
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6
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Chen D, Li Y, Li X, Savidge T, Qian Y, Fan X. Factors determining the enzyme catalytic power caused by noncovalent interactions: Charge alterations in enzyme active sites. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2021.103611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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7
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Kemp MT, Nichols DA, Zhang X, Defrees K, Na I, Renslo AR, Chen Y. Mutation of the conserved Asp-Asp pair impairs the structure, function, and inhibition of CTX-M Class A β-lactamase. FEBS Lett 2021; 595:2981-2994. [PMID: 34704263 DOI: 10.1002/1873-3468.14215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/07/2021] [Accepted: 10/21/2021] [Indexed: 11/07/2022]
Abstract
The Asp233-Asp246 pair is highly conserved in Class A β-lactamases, which hydrolyze β-lactam antibiotics. Here, we characterize its function using CTX-M-14 β-lactamase. The D233N mutant displayed decreased activity that is substrate-dependent, with reductions in kcat /Km ranging from 20% for nitrocefin to 6-fold for cefotaxime. In comparison, the mutation reduced the binding of a known reversible inhibitor by 10-fold. The mutant structures showed movement of the 213-219 loop and the loss of the Thr216-Thr235 hydrogen bond, which was restored by inhibitor binding. Mutagenesis of Thr216 further highlighted its contribution to CTX-M activity. These results demonstrate the importance of the aspartate pair to CTX-M hydrolysis of substrates with bulky side chains, while suggesting increased protein flexibility as a means to evolve drug resistance.
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Affiliation(s)
- M Trent Kemp
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Derek A Nichols
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Xiujun Zhang
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Kyle Defrees
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
| | - Insung Na
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
| | - Adam R Renslo
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL, USA
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8
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Veldman W, Liberato MV, Souza VP, Almeida VM, Marana SR, Tastan Bishop Ö, Polikarpov I. Differences in Gluco and Galacto Substrate-Binding Interactions in a Dual 6Pβ-Glucosidase/6Pβ-Galactosidase Glycoside Hydrolase 1 Enzyme from Bacillus licheniformis. J Chem Inf Model 2021; 61:4554-4570. [PMID: 34423980 DOI: 10.1021/acs.jcim.1c00413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial glycoside hydrolase 1 (GH1) enzymes with 6-phospho-β-galactosidase and 6-phospho-β-glucosidase activities have the important task of releasing phosphorylated and nonphosphorylated monosaccharides into the cytoplasm. Curiously, dual 6-phospho-β-galactosidase/6-phospho-β-glucosidase (dual-phospho) enzymes have broad specificity and are able to hydrolyze galacto- and gluco-derived substrates. This study investigates the structure and substrate specificity of a GH family 1 enzyme from Bacillus licheniformis, hereafter known as BlBglC. The enzyme structure has been solved, and sequence analysis, molecular dynamics simulations, and binding free energy calculations offered evidence of dual-phospho activity. Both test ligands p-nitrophenyl-β-d-galactoside-6-phosphate (PNP6Pgal) and p-nitrophenyl-β-d-glucoside-6-phosphate (PNP6Pglc) demonstrated strong binding to BlBglC although the pose and interactions of the PNP6Pglc triplicates were slightly more consistent. Interestingly, known specificity-inducing residues, Gln23 and Trp433, bind strongly to the ligand O3 hydroxyl group in the PNP6Pgal-BlBglC complex and to the ligand O4 hydroxyl group in the PNP6Pglc-BlBglC complex. Additionally, the BlBglC-His124 residue is a major contributor of hydrogen bonds to the PNP6Pgal O3 hydroxyl group but does not form any hydrogen bonds with PNP6Pglc. On the other hand, BlBglC residues Tyr173, Tyr301, Gln302, and Thr321 form hydrogen bonds with PNP6Pglc but not PNP6Pgal. These findings provide important details of the broad specificity of dual-phospho activity GH1 enzymes.
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Affiliation(s)
- Wayde Veldman
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
| | | | - Valquiria P Souza
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05508-000, Brazil
| | - Vitor M Almeida
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05508-000, Brazil
| | - Sandro R Marana
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo 05508-000, Brazil
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, Brazil
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9
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Immel JR, Chilamari M, Bloom S. Combining flavin photocatalysis with parallel synthesis: a general platform to optimize peptides with non-proteinogenic amino acids. Chem Sci 2021; 12:10083-10091. [PMID: 34377401 PMCID: PMC8317666 DOI: 10.1039/d1sc02562g] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/28/2021] [Indexed: 02/06/2023] Open
Abstract
Most peptide drugs contain non-proteinogenic amino acids (NPAAs), born out through extensive structure-activity relationship (SAR) studies using solid-phase peptide synthesis (SPPS). Synthetically laborious and expensive to manufacture, NPAAs also can have poor coupling efficiencies allowing only a small fraction to be sampled by conventional SPPS. To gain general access to NPAA-containing peptides, we developed a first-generation platform that merges contemporary flavin photocatalysis with parallel synthesis to simultaneously make, purify, quantify, and even test up to 96 single-NPAA peptide variants via the unique combination of boronic acids and a dehydroalanine residue in a peptide. We showcase the power of our newly minted platform to introduce NPAAs of diverse chemotypes-aliphatic, aromatic, heteroaromatic-directly into peptides, including 15 entirely new residues, and to evolve a simple proteinogenic peptide into an unnatural inhibitor of thrombin by non-classical peptide SAR.
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Affiliation(s)
- Jacob R Immel
- Department of Medicinal Chemistry, The University of Kansas Integrated Science Building Lawrence KS 66045 USA
| | - Maheshwerreddy Chilamari
- Department of Medicinal Chemistry, The University of Kansas Integrated Science Building Lawrence KS 66045 USA
| | - Steven Bloom
- Department of Medicinal Chemistry, The University of Kansas Integrated Science Building Lawrence KS 66045 USA
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10
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Pinney MM, Mokhtari DA, Akiva E, Yabukarski F, Sanchez DM, Liang R, Doukov T, Martinez TJ, Babbitt PC, Herschlag D. Parallel molecular mechanisms for enzyme temperature adaptation. Science 2021; 371:371/6533/eaay2784. [PMID: 33674467 DOI: 10.1126/science.aay2784] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/23/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022]
Abstract
The mechanisms that underly the adaptation of enzyme activities and stabilities to temperature are fundamental to our understanding of molecular evolution and how enzymes work. Here, we investigate the molecular and evolutionary mechanisms of enzyme temperature adaption, combining deep mechanistic studies with comprehensive sequence analyses of thousands of enzymes. We show that temperature adaptation in ketosteroid isomerase (KSI) arises primarily from one residue change with limited, local epistasis, and we establish the underlying physical mechanisms. This residue change occurs in diverse KSI backgrounds, suggesting parallel adaptation to temperature. We identify residues associated with organismal growth temperature across 1005 diverse bacterial enzyme families, suggesting widespread parallel adaptation to temperature. We assess the residue properties, molecular interactions, and interaction networks that appear to underly temperature adaptation.
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Affiliation(s)
- Margaux M Pinney
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.
| | - Daniel A Mokhtari
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
| | - Eyal Akiva
- Department of Bioengineering and Therapeutic Sciences and Quantitative Biosciences Institute, University of California, San Francisco, CA 94158, USA
| | - Filip Yabukarski
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.,Chan Zuckerberg Biohub, San Francisco, CA 94110, USA
| | - David M Sanchez
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.,Department of Photon Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Ruibin Liang
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.,Department of Photon Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Tzanko Doukov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Todd J Martinez
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.,Department of Photon Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Patricia C Babbitt
- Department of Bioengineering and Therapeutic Sciences and Quantitative Biosciences Institute, University of California, San Francisco, CA 94158, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA. .,Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA
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11
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Kemp MT, Lewandowski EM, Chen Y. Low barrier hydrogen bonds in protein structure and function. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2021; 1869:140557. [PMID: 33148530 PMCID: PMC7736181 DOI: 10.1016/j.bbapap.2020.140557] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/17/2020] [Accepted: 10/22/2020] [Indexed: 01/05/2023]
Abstract
Low-barrier hydrogen bonds (LBHBs) are a special type of short hydrogen bond (HB) that is characterized by the equal sharing of a hydrogen atom. The existence and catalytic role of LBHBs in proteins has been intensely contested. Advancements in X-ray and neutron diffraction methods has revealed delocalized hydrogen atoms involved in potential LBHBs in a number of proteins, while also demonstrating that short HBs are not necessarily LBHBs. More importantly, a series of experiments on ketosteroid isomerase (KSI) have suggested that LBHBs are significantly stronger than standard HBs in the protein microenvironment in terms of enthalpy, but not free energy. The discrepancy between the enthalpy and free energy of LBHBs offers clues to the challenges, and potential solutions, of the LBHB debate, where the unique strength of LBHBs plays a special role in the kinetic processes of enzyme function and structure, together with other molecular forces in a pre-organized environment.
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Affiliation(s)
- M Trent Kemp
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States
| | - Eric M Lewandowski
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, Florida 33612, United States.
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12
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Assessment of enzyme active site positioning and tests of catalytic mechanisms through X-ray-derived conformational ensembles. Proc Natl Acad Sci U S A 2020; 117:33204-33215. [PMID: 33376217 DOI: 10.1073/pnas.2011350117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
How enzymes achieve their enormous rate enhancements remains a central question in biology, and our understanding to date has impacted drug development, influenced enzyme design, and deepened our appreciation of evolutionary processes. While enzymes position catalytic and reactant groups in active sites, physics requires that atoms undergo constant motion. Numerous proposals have invoked positioning or motions as central for enzyme function, but a scarcity of experimental data has limited our understanding of positioning and motion, their relative importance, and their changes through the enzyme's reaction cycle. To examine positioning and motions and test catalytic proposals, we collected "room temperature" X-ray crystallography data for Pseudomonas putida ketosteroid isomerase (KSI), and we obtained conformational ensembles for this and a homologous KSI from multiple PDB crystal structures. Ensemble analyses indicated limited change through KSI's reaction cycle. Active site positioning was on the 1- to 1.5-Å scale, and was not exceptional compared to noncatalytic groups. The KSI ensembles provided evidence against catalytic proposals invoking oxyanion hole geometric discrimination between the ground state and transition state or highly precise general base positioning. Instead, increasing or decreasing positioning of KSI's general base reduced catalysis, suggesting optimized Ångstrom-scale conformational heterogeneity that allows KSI to efficiently catalyze multiple reaction steps. Ensemble analyses of surrounding groups for WT and mutant KSIs provided insights into the forces and interactions that allow and limit active-site motions. Most generally, this ensemble perspective extends traditional structure-function relationships, providing the basis for a new era of "ensemble-function" interrogation of enzymes.
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13
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Shahzadi Z, Abbas G, Azam SS. Relational dynamics obtained through simulation studies of thioredoxin reductase: From a multi-drug resistant Entamoeba histolytica. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Agostini A, Meneghin E, Gewehr L, Pedron D, Palm DM, Carbonera D, Paulsen H, Jaenicke E, Collini E. How water-mediated hydrogen bonds affect chlorophyll a/b selectivity in Water-Soluble Chlorophyll Protein. Sci Rep 2019; 9:18255. [PMID: 31796824 PMCID: PMC6890793 DOI: 10.1038/s41598-019-54520-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/14/2019] [Indexed: 01/15/2023] Open
Abstract
The Water-Soluble Chlorophyll Protein (WSCP) of Brassicaceae is a remarkably stable tetrapyrrole-binding protein that, by virtue of its simple design, is an exceptional model to investigate the interactions taking place between pigments and their protein scaffold and how they affect the photophysical properties and the functionality of the complexes. We investigated variants of WSCP from Lepidium virginicum (Lv) and Brassica oleracea (Bo), reconstituted with Chlorophyll (Chl) b, to determine the mechanisms by which the different Chl binding sites control their Chl a/b specificities. A combined Raman and crystallographic investigation has been employed, aimed to characterize in detail the hydrogen-bond network involving the formyl group of Chl b. The study revealed a variable degree of conformational freedom of the hydrogen bond networks among the WSCP variants, and an unexpected mixed presence of hydrogen-bonded and not hydrogen-bonded Chls b in the case of the L91P mutant of Lv WSCP. These findings helped to refine the description of the mechanisms underlying the different Chl a/b specificities of WSCP versions, highlighting the importance of the structural rigidity of the Chl binding site in the vicinity of the Chl b formyl group in granting a strong selectivity to binding sites.
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Affiliation(s)
- Alessandro Agostini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy. .,Institute of Molecular Physiology, Johannes Gutenberg-University, Johannes-von-Müller-Weg 6, 55128, Mainz, Germany.
| | - Elena Meneghin
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Lucas Gewehr
- Institute of Molecular Physiology, Johannes Gutenberg-University, Johannes-von-Müller-Weg 6, 55128, Mainz, Germany
| | - Danilo Pedron
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Daniel M Palm
- Institute of Molecular Physiology, Johannes Gutenberg-University, Johannes-von-Müller-Weg 6, 55128, Mainz, Germany
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy
| | - Harald Paulsen
- Institute of Molecular Physiology, Johannes Gutenberg-University, Johannes-von-Müller-Weg 6, 55128, Mainz, Germany
| | - Elmar Jaenicke
- Institute of Molecular Physiology, Johannes Gutenberg-University, Jakob-Welder-Weg 26, 55128, Mainz, Germany
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131, Padova, Italy.
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15
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Pinney MM, Natarajan A, Yabukarski F, Sanchez DM, Liu F, Liang R, Doukov T, Schwans JP, Martinez TJ, Herschlag D. Structural Coupling Throughout the Active Site Hydrogen Bond Networks of Ketosteroid Isomerase and Photoactive Yellow Protein. J Am Chem Soc 2018; 140:9827-9843. [DOI: 10.1021/jacs.8b01596] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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16
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Abstract
Hydrogen bonds play integral roles in biological structure, function, and conformational dynamics and are fundamental to life as it has evolved on Earth. However, our understanding of these fundamental and ubiquitous interactions has seemed fractured and incomplete, and it has been difficult to extract generalities and principles about hydrogen bonds despite thousands of papers published on this topic, perhaps in part because of the expanse of this subject and the density of studies. Fortunately, recent hydrogen bond proposals, discussions, and debates have stimulated new tests and models and have led to a remarkably simple picture of the structure of hydrogen bonds. This knowledge also provides clarity concerning hydrogen bond energetics, limiting and simplifying the factors that need be considered. Herein we recount the advances that have led to this simpler view of hydrogen bond structure, dynamics, and energetics. A quantitative predictive model for hydrogen bond length can now be broadly and deeply applied to evaluate current proposals and to uncover structural features of proteins, their conformational restraints, and their correlated motions. In contrast, a quantitative energetic description of molecular recognition and catalysis by proteins remains an important ongoing challenge, although our improved understanding of hydrogen bonds may aid in testing predictions from current and future models. We close by codifying our current state of understanding into five "Rules for Hydrogen Bonding" that may provide a foundation for understanding and teaching about these vital interactions and for building toward a deeper understanding of hydrogen bond energetics.
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17
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Wang L, Fried SD, Markland TE. Proton Network Flexibility Enables Robustness and Large Electric Fields in the Ketosteroid Isomerase Active Site. J Phys Chem B 2017; 121:9807-9815. [DOI: 10.1021/acs.jpcb.7b06985] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lu Wang
- Department
of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Stephen D. Fried
- Medical Research
Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, U.K
| | - Thomas E. Markland
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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18
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Abstract
What happens inside an enzyme's active site to allow slow and difficult chemical reactions to occur so rapidly? This question has occupied biochemists' attention for a long time. Computer models of increasing sophistication have predicted an important role for electrostatic interactions in enzymatic reactions, yet this hypothesis has proved vexingly difficult to test experimentally. Recent experiments utilizing the vibrational Stark effect make it possible to measure the electric field a substrate molecule experiences when bound inside its enzyme's active site. These experiments have provided compelling evidence supporting a major electrostatic contribution to enzymatic catalysis. Here, we review these results and develop a simple model for electrostatic catalysis that enables us to incorporate disparate concepts introduced by many investigators to describe how enzymes work into a more unified framework stressing the importance of electric fields at the active site.
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Affiliation(s)
- Stephen D Fried
- Proteins and Nucleic Acid Chemistry Division, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom;
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305;
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19
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Wu Y, Boxer SG. A Critical Test of the Electrostatic Contribution to Catalysis with Noncanonical Amino Acids in Ketosteroid Isomerase. J Am Chem Soc 2016; 138:11890-5. [PMID: 27545569 PMCID: PMC5063566 DOI: 10.1021/jacs.6b06843] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The vibrational Stark effect (VSE) has been used to measure the electric field in the active site of ketosteroid isomerase (KSI). These measured fields correlate with ΔG(⧧) in a series of conventional mutants, yielding an estimate for the electrostatic contribution to catalysis (Fried et al. Science 2014, 346, 1510-1513). In this work we test this result with much more conservative variants in which individual Tyr residues in the active site are replaced by 3-chlorotyrosine via amber suppression. The electric fields sensed at the position of the carbonyl bond involved in charge displacement during catalysis were characterized using the VSE, where the field sensitivity has been calibrated by vibrational Stark spectroscopy, solvatochromism, and MD simulations. A linear relationship is observed between the electric field and ΔG(⧧) that interpolates between wild-type and more drastic conventional mutations, reinforcing the evaluation of the electrostatic contribution to catalysis in KSI. A simplified model and calculation are developed to estimate changes in the electric field accompanying changes in the extended hydrogen-bond network in the active site. The results are consistent with a model in which the O-H group of a key active site tyrosine functions by imposing a static electrostatic potential onto the carbonyl bond. The model suggests that the contribution to catalysis from the active site hydrogen bonds is of similar weight to the distal interactions from the rest of the protein. A similar linear correlation was also observed between the proton affinity of KSI's active site and the catalytic rate, suggesting a direct connection between the strength of the H-bond and the electric field it exerts.
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Affiliation(s)
- Yufan Wu
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
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20
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Oyala PH, Ravichandran KR, Funk MA, Stucky PA, Stich TA, Drennan CL, Britt RD, Stubbe J. Biophysical Characterization of Fluorotyrosine Probes Site-Specifically Incorporated into Enzymes: E. coli Ribonucleotide Reductase As an Example. J Am Chem Soc 2016; 138:7951-64. [PMID: 27276098 PMCID: PMC4929525 DOI: 10.1021/jacs.6b03605] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Fluorinated tyrosines
(FnY’s, n = 2
and 3) have been site-specifically incorporated into E. coli class Ia ribonucleotide reductase (RNR) using the
recently evolved M. jannaschii Y-tRNA synthetase/tRNA
pair. Class Ia RNRs require four redox active Y’s, a stable
Y radical (Y·) in the β subunit (position 122 in E. coli), and three transiently oxidized Y’s (356
in β and 731 and 730 in α) to initiate the radical-dependent
nucleotide reduction process. FnY (3,5;
2,3; 2,3,5; and 2,3,6) incorporation in place of Y122-β
and the X-ray structures of each resulting β with a diferric
cluster are reported and compared with wt-β2 crystallized under
the same conditions. The essential diferric-FnY· cofactor is self-assembled from apo FnY-β2, Fe2+, and O2 to produce ∼1
Y·/β2 and ∼3 Fe3+/β2. The FnY· are stable and active in nucleotide
reduction with activities that vary from 5% to 85% that of wt-β2.
Each FnY·-β2 has been characterized
by 9 and 130 GHz electron paramagnetic resonance and high-field electron
nuclear double resonance spectroscopies. The hyperfine interactions
associated with the 19F nucleus provide unique signatures
of each FnY· that are readily distinguishable
from unlabeled Y·’s. The variability of the abiotic FnY pKa’s
(6.4 to 7.8) and reduction potentials (−30 to +130 mV relative
to Y at pH 7.5) provide probes of enzymatic reactions proposed to
involve Y·’s in catalysis and to investigate the importance
and identity of hopping Y·’s within redox active proteins
proposed to protect them from uncoupled radical chemistry.
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Affiliation(s)
- Paul H Oyala
- Department of Chemistry, University of California, Davis , One Shields Avenue, Davis, California 95616, United States
| | | | | | - Paul A Stucky
- Department of Chemistry, University of California, Davis , One Shields Avenue, Davis, California 95616, United States
| | - Troy A Stich
- Department of Chemistry, University of California, Davis , One Shields Avenue, Davis, California 95616, United States
| | - Catherine L Drennan
- Howard Hughes Medical Institute, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - R David Britt
- Department of Chemistry, University of California, Davis , One Shields Avenue, Davis, California 95616, United States
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21
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Chen D, Oezguen N, Urvil P, Ferguson C, Dann SM, Savidge TC. Regulation of protein-ligand binding affinity by hydrogen bond pairing. SCIENCE ADVANCES 2016; 2:e1501240. [PMID: 27051863 PMCID: PMC4820369 DOI: 10.1126/sciadv.1501240] [Citation(s) in RCA: 345] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 02/05/2016] [Indexed: 05/20/2023]
Abstract
Hydrogen (H)-bonds potentiate diverse cellular functions by facilitating molecular interactions. The mechanism and the extent to which H-bonds regulate molecular interactions are a largely unresolved problem in biology because the H-bonding process continuously competes with bulk water. This interference may significantly alter our understanding of molecular function, for example, in the elucidation of the origin of enzymatic catalytic power. We advance this concept by showing that H-bonds regulate molecular interactions via a hitherto unappreciated donor-acceptor pairing mechanism that minimizes competition with water. On the basis of theoretical and experimental correlations between H-bond pairings and their effects on ligand binding affinity, we demonstrate that H-bonds enhance receptor-ligand interactions when both the donor and acceptor have either significantly stronger or significantly weaker H-bonding capabilities than the hydrogen and oxygen atoms in water. By contrast, mixed strong-weak H-bond pairings decrease ligand binding affinity due to interference with bulk water, offering mechanistic insight into why indiscriminate strengthening of receptor-ligand H-bonds correlates poorly with experimental binding affinity. Further support for the H-bond pairing principle is provided by the discovery and optimization of lead compounds targeting dietary melamine and Clostridium difficile toxins, which are not realized by traditional drug design methods. Synergistic H-bond pairings have therefore evolved in the natural design of high-affinity binding and provide a new conceptual framework to evaluate the H-bonding process in biological systems. Our findings may also guide wider applications of competing H-bond pairings in lead compound design and in determining the origin of enzymatic catalytic power.
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Affiliation(s)
- Deliang Chen
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Chemistry and Chemical Engineering College, Gannan Normal University, Ganzhou, Jiangxi 341000, P. R. China
| | - Numan Oezguen
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, TX 77030, USA
| | - Petri Urvil
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, TX 77030, USA
| | | | - Sara M. Dann
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tor C. Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, TX 77030, USA
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22
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Wu Y, Fried SD, Boxer SG. Dissecting Proton Delocalization in an Enzyme's Hydrogen Bond Network with Unnatural Amino Acids. Biochemistry 2015; 54:7110-9. [PMID: 26571340 DOI: 10.1021/acs.biochem.5b00958] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extended hydrogen bond networks are a common structural motif of enzymes. A recent analysis proposed quantum delocalization of protons as a feature present in the hydrogen bond network spanning a triad of tyrosines (Y(16), Y(32), and Y(57)) in the active site of ketosteroid isomerase (KSI), contributing to its unusual acidity and large isotope shift. In this study, we utilized amber suppression to substitute each tyrosine residue with 3-chlorotyrosine to test the delocalization model and the proton affinity balance in the triad. X-ray crystal structures of each variant demonstrated that the structure, notably the O-O distances within the triad, was unaffected by 3-chlorotyrosine substitutions. The changes in the cluster's acidity and the acidity's isotope dependence in these variants were assessed via UV-vis spectroscopy and the proton sharing pattern among individual residues with (13)C nuclear magnetic resonance. Our data show pKa detuning at each triad residue alters the proton delocalization behavior in the H-bond network. The extra stabilization energy necessary for the unusual acidity mainly comes from the strong interactions between Y(57) and Y(16). This is further enabled by Y(32), which maintains the right geometry and matched proton affinity in the triad. This study provides a rich picture of the energetics of the hydrogen bond network in enzymes for further model refinement.
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Affiliation(s)
- Yufan Wu
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
| | - Stephen D Fried
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
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23
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Dennig A, Busto E, Kroutil W, Faber K. Biocatalytic One-Pot Synthesis of l-Tyrosine Derivatives from Monosubstituted Benzenes, Pyruvate, and Ammonia. ACS Catal 2015. [DOI: 10.1021/acscatal.5b02129] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander Dennig
- Department of Chemistry,
Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse
28, A-8010 Graz, Austria
| | - Eduardo Busto
- Department of Chemistry,
Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse
28, A-8010 Graz, Austria
| | - Wolfgang Kroutil
- Department of Chemistry,
Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse
28, A-8010 Graz, Austria
| | - Kurt Faber
- Department of Chemistry,
Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse
28, A-8010 Graz, Austria
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24
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Onwukwe GU, Koski MK, Pihko P, Schmitz W, Wierenga RK. Structures of yeast peroxisomal Δ(3),Δ(2)-enoyl-CoA isomerase complexed with acyl-CoA substrate analogues: the importance of hydrogen-bond networks for the reactivity of the catalytic base and the oxyanion hole. ACTA ACUST UNITED AC 2015; 71:2178-91. [PMID: 26527136 DOI: 10.1107/s139900471501559x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/19/2015] [Indexed: 11/10/2022]
Abstract
Δ(3),Δ(2)-Enoyl-CoA isomerases (ECIs) catalyze the shift of a double bond from 3Z- or 3E-enoyl-CoA to 2E-enoyl-CoA. ECIs are members of the crotonase superfamily. The crotonase framework is used by many enzymes to catalyze a wide range of reactions on acyl-CoA thioesters. The thioester O atom is bound in a conserved oxyanion hole. Here, the mode of binding of acyl-CoA substrate analogues to peroxisomal Saccharomyces cerevisiae ECI (ScECI2) is described. The best defined part of the bound acyl-CoA molecules is the 3',5'-diphosphate-adenosine moiety, which interacts with residues of loop 1 and loop 2, whereas the pantetheine part is the least well defined. The catalytic base, Glu158, is hydrogen-bonded to the Asn101 side chain and is further hydrogen-bonded to the side chain of Arg100 in the apo structure. Arg100 is completely buried in the apo structure and a conformational change of the Arg100 side chain appears to be important for substrate binding and catalysis. The oxyanion hole is formed by the NH groups of Ala70 (loop 2) and Leu126 (helix 3). The O atoms of the corresponding peptide units, Gly69 O and Gly125 O, are both part of extensive hydrogen-bond networks. These hydrogen-bond networks are a conserved feature of the crotonase oxyanion hole and their importance for catalysis is discussed.
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Affiliation(s)
- Goodluck U Onwukwe
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - M Kristian Koski
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Petri Pihko
- Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland
| | - Werner Schmitz
- Department of Biochemistry and Molecular Biology, University of Würzburg, Biozentrum, Am Hubland, 97074 Würzburg, Germany
| | - Rik K Wierenga
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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25
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Nichols DA, Hargis JC, Sanishvili R, Jaishankar P, Defrees K, Smith E, Wang KK, Prati F, Renslo AR, Woodcock HL, Chen Y. Ligand-Induced Proton Transfer and Low-Barrier Hydrogen Bond Revealed by X-ray Crystallography. J Am Chem Soc 2015; 137:8086-95. [PMID: 26057252 PMCID: PMC4530788 DOI: 10.1021/jacs.5b00749] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ligand binding can change the pKa of protein residues and influence enzyme catalysis. Herein, we report three ultrahigh resolution X-ray crystal structures of CTX-M β-lactamase, directly visualizing protonation state changes along the enzymatic pathway: apo protein at 0.79 Å, precovalent complex with nonelectrophilic ligand at 0.89 Å, and acylation transition state (TS) analogue at 0.84 Å. Binding of the noncovalent ligand induces a proton transfer from the catalytic Ser70 to the negatively charged Glu166, and the formation of a low-barrier hydrogen bond (LBHB) between Ser70 and Lys73, with a length of 2.53 Å and the shared hydrogen equidistant from the heteroatoms. QM/MM reaction path calculations determined the proton transfer barrier to be 1.53 kcal/mol. The LBHB is absent in the other two structures although Glu166 remains neutral in the covalent complex. Our data represents the first X-ray crystallographic example of a hydrogen engaged in an enzymatic LBHB, and demonstrates that desolvation of the active site by ligand binding can provide a protein microenvironment conducive to LBHB formation. It also suggests that LBHBs may contribute to stabilization of the TS in general acid/base catalysis together with other preorganized features of enzyme active sites. These structures reconcile previous experimental results suggesting alternatively Glu166 or Lys73 as the general base for acylation, and underline the importance of considering residue protonation state change when modeling protein-ligand interactions. Additionally, the observation of another LBHB (2.47 Å) between two conserved residues, Asp233 and Asp246, suggests that LBHBs may potentially play a special structural role in proteins.
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Affiliation(s)
- Derek A. Nichols
- University of South Florida College of Medicine, Dept of Molecular Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, FL 33612
| | | | - Ruslan Sanishvili
- GMCA@APS, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439
| | - Priyadarshini Jaishankar
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, University of California San Francisco, 1700 4 Street, Byers Hall S504, San Francisco, CA 94158
| | - Kyle Defrees
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, University of California San Francisco, 1700 4 Street, Byers Hall S504, San Francisco, CA 94158
| | - Emmanuel Smith
- University of South Florida College of Medicine, Dept of Molecular Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, FL 33612
| | - Kenneth K. Wang
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Fabio Prati
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Adam R. Renslo
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, University of California San Francisco, 1700 4 Street, Byers Hall S504, San Francisco, CA 94158
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida 33620
| | - Yu Chen
- University of South Florida College of Medicine, Dept of Molecular Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, FL 33612
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26
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Sigala PA, Ruben EA, Liu CW, Piccoli PMB, Hohenstein EG, Martínez TJ, Schultz AJ, Herschlag D. Determination of Hydrogen Bond Structure in Water versus Aprotic Environments To Test the Relationship Between Length and Stability. J Am Chem Soc 2015; 137:5730-40. [PMID: 25871450 DOI: 10.1021/ja512980h] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hydrogen bonds profoundly influence the architecture and activity of biological macromolecules. Deep appreciation of hydrogen bond contributions to biomolecular function thus requires a detailed understanding of hydrogen bond structure and energetics and the relationship between these properties. Hydrogen bond formation energies (ΔGf) are enormously more favorable in aprotic solvents than in water, and two classes of contributing factors have been proposed to explain this energetic difference, focusing respectively on the isolated and hydrogen-bonded species: (I) water stabilizes the dissociated donor and acceptor groups much better than aprotic solvents, thereby reducing the driving force for hydrogen bond formation; and (II) water lengthens hydrogen bonds compared to aprotic environments, thereby decreasing the potential energy within the hydrogen bond. Each model has been proposed to provide a dominant contribution to ΔGf, but incisive tests that distinguish the importance of these contributions are lacking. Here we directly test the structural basis of model II. Neutron crystallography, NMR spectroscopy, and quantum mechanical calculations demonstrate that O-H···O hydrogen bonds in crystals, chloroform, acetone, and water have nearly identical lengths and very similar potential energy surfaces despite ΔGf differences >8 kcal/mol across these solvents. These results rule out a substantial contribution from solvent-dependent differences in hydrogen bond structure and potential energy after association (model II) and thus support the conclusion that differences in hydrogen bond ΔGf are predominantly determined by solvent interactions with the dissociated groups (model I). These findings advance our understanding of universal hydrogen-bonding interactions and have important implications for biology and engineering.
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Affiliation(s)
| | | | | | - Paula M B Piccoli
- §Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | | | | | - Arthur J Schultz
- §Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
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27
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Fraser SA, Easton CJ. Biosynthetic Incorporation of Fluorinated Amino Acids into Peptides and Proteins. Aust J Chem 2015. [DOI: 10.1071/ch14356] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Native and engineered protein biosynthetic machinery processes a wide range of fluorinated α-amino acids for incorporation into peptides and proteins, either as substitutes for structurally similar amino acids normally found in proteins, or as additional ones. In the former case, replacement occurs wherever the normal amino acid is encoded, while the latter method is site-specific. The fluorinated peptides have a diverse variety of interesting properties. The biochemical synthetic methods are straightforward, to the point that they should routinely be assessed as alternatives to traditional solid- and solution-phase peptide synthesis.
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