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Pramanik S, Steinert RM, Mitchell-Koch KR, Bowman-James K. Structural Insight on Supramolecular Polyion Salts: Inositol Hexaphosphate Enclosed in Cationic Macrocyclic Clusters. Chemistry 2023; 29:e202301764. [PMID: 37544911 DOI: 10.1002/chem.202301764] [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: 06/03/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023]
Abstract
Supramolecular macrocyclic forces have been used to trap phytate, myo-inositol-1,2,3,4,5,6-hexakisphosphate, a key bioanion with multiple roles in metabolic processes. Due to the complex chemistry of six multivalent phosphates surrounding the small, cyclic inositol framework, crystallographic information of simple phytate salts has been elusive. This report represents a combined crystallographic, theoretical, and solution binding investigation of a supramolecular macrocyclic complex of phytate. Together, the results provide significant insight to phytate's intramolecular and intermolecular interactions at the microenvironment level. The macrocycle-phytate aggregates consist of phytate anionic pairs, each partly sandwiched by two 24-membered, amide/amine-based cationic macrocycles. The phytate ion pairs hold the tetrameric macrocyclic array together by six strong intermolecular hydrogen bonds. Both phytates crystallize in 1a5e phosphate conformations (one axial (P2) and five equatorial phosphates). Solution NMR binding studies in 1 : 1 DMSO-d6 : D2 O indicate 2 : 1 macrocycle:phytate associations, suggesting that the sandwich-like nature of the complex holds together in solution. DFT studies indicate the likely occurrence of dynamic intramolecular interchange of phosphate protons, as well as important roles for the axial (P2) phosphate in both intramolecular and intermolecular hydrogen bonding interactions.
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Affiliation(s)
- Subhamay Pramanik
- Department of Chemistry, University of Kansas, Lawrence, Kansas, 66045, USA
| | - Ryan M Steinert
- Department of Chemistry, Wichita State University, Wichita, Kansas, 67260, USA
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2
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Zhou S, Liu Y, Wang S, Wang L. Chemical features and machine learning assisted predictions of protein-ligand short hydrogen bonds. Sci Rep 2023; 13:13741. [PMID: 37612311 PMCID: PMC10447522 DOI: 10.1038/s41598-023-40614-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
There are continuous efforts to elucidate the structure and biological functions of short hydrogen bonds (SHBs), whose donor and acceptor heteroatoms reside more than 0.3 Å closer than the sum of their van der Waals radii. In this work, we evaluate 1070 atomic-resolution protein structures and characterize the common chemical features of SHBs formed between the side chains of amino acids and small molecule ligands. We then develop a machine learning assisted prediction of protein-ligand SHBs (MAPSHB-Ligand) model and reveal that the types of amino acids and ligand functional groups as well as the sequence of neighboring residues are essential factors that determine the class of protein-ligand hydrogen bonds. The MAPSHB-Ligand model and its implementation on our web server enable the effective identification of protein-ligand SHBs in proteins, which will facilitate the design of biomolecules and ligands that exploit these close contacts for enhanced functions.
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Affiliation(s)
| | - Yuanhao Liu
- Department of Statistics, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, 08854, USA
| | - Sijian Wang
- Department of Statistics, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, 08854, USA.
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3
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Sun D, Wu Z, Zhang X, Yang J, Zhao Y, Nam W, Wang Y. Brønsted Acids Promote Olefin Oxidations by Bioinspired Nonheme Co III(PhIO)(OH) Complexes: A Role for Low-Barrier Hydrogen Bonds. J Am Chem Soc 2023; 145:5739-5749. [PMID: 36867878 DOI: 10.1021/jacs.2c12307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Introduction of Brønsted acids into biomimetic nonheme reactions promotes the oxidative ability of metal-oxygen complexes significantly. However, the molecular machinery of the promoted effects is missing. Herein, a comprehensive investigation of styrene oxidation by a cobalt(III)-iodosylbenzene complex, [(TQA)CoIII(OIPh)(OH)]2+ (1, TQA = tris(2-quinolylmethyl)amine), in the presence and absence of triflic acid (HOTf) was performed using density functional theory calculations. Results revealed for the first time that there is a low-barrier hydrogen bond (LBHB) between HOTf and the hydroxyl ligand of 1, which forms two valence-resonance structures [(TQA)CoIII(OIPh)(HO---HOTf)]2+ (1LBHB) and [(TQA)CoIII(OIPh)(H2O--OTf-)]2+ (1'LBHB). Due to the oxo-wall, these complexes (1LBHB and 1'LBHB) cannot convert to high-valent cobalt-oxyl species. Instead, styrene oxidation by these oxidants (1LBHB and 1'LBHB) shows novel spin-state selectivity, i.e., on the ground closed-shell singlet state, styrene is oxidized to an epoxide, whereas on the excited triplet and quintet states, an aldehyde product, phenylacetaldehyde, is formed. The preferred pathway is styrene oxidation by 1'LBHB, which is initiated by a rate-limiting bond-formation-coupled electron transfer process with an energy barrier of 12.2 kcal mol-1. The nascent PhIO-styrene-radical-cation intermediate undergoes an intramolecular rearrangement to produce an aldehyde. The halogen bond between the OH-/H2O ligand and the iodine of PhIO modulates the activity of the cobalt-iodosylarene complexes 1LBHB and 1'LBHB. These new mechanistic findings enrich our knowledge of nonheme chemistry and hypervalent iodine chemistry and will play a positive role in the rational design of new catalysts.
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Affiliation(s)
- Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Zhimin Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Xuan Zhang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Jindou Yang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, China
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Kozlova MI, Shalaeva DN, Dibrova DV, Mulkidjanian AY. Common Mechanism of Activated Catalysis in P-loop Fold Nucleoside Triphosphatases-United in Diversity. Biomolecules 2022; 12:1346. [PMID: 36291556 PMCID: PMC9599734 DOI: 10.3390/biom12101346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/20/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
To clarify the obscure hydrolysis mechanism of ubiquitous P-loop-fold nucleoside triphosphatases (Walker NTPases), we analysed the structures of 3136 catalytic sites with bound Mg-NTP complexes or their analogues. Our results are presented in two articles; here, in the second of them, we elucidated whether the Walker A and Walker B sequence motifs-common to all P-loop NTPases-could be directly involved in catalysis. We found that the hydrogen bonds (H-bonds) between the strictly conserved, Mg-coordinating Ser/Thr of the Walker A motif ([Ser/Thr]WA) and aspartate of the Walker B motif (AspWB) are particularly short (even as short as 2.4 ångströms) in the structures with bound transition state (TS) analogues. Given that a short H-bond implies parity in the pKa values of the H-bond partners, we suggest that, in response to the interactions of a P-loop NTPase with its cognate activating partner, a proton relocates from [Ser/Thr]WA to AspWB. The resulting anionic [Ser/Thr]WA alkoxide withdraws a proton from the catalytic water molecule, and the nascent hydroxyl attacks the gamma phosphate of NTP. When the gamma-phosphate breaks away, the trapped proton at AspWB passes by the Grotthuss relay via [Ser/Thr]WA to beta-phosphate and compensates for its developing negative charge that is thought to be responsible for the activation barrier of hydrolysis.
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Affiliation(s)
- Maria I. Kozlova
- School of Physics, Osnabrueck University, D-49069 Osnabrueck, Germany
| | - Daria N. Shalaeva
- School of Physics, Osnabrueck University, D-49069 Osnabrueck, Germany
| | - Daria V. Dibrova
- School of Physics, Osnabrueck University, D-49069 Osnabrueck, Germany
| | - Armen Y. Mulkidjanian
- School of Physics, Osnabrueck University, D-49069 Osnabrueck, Germany
- Center of Cellular Nanoanalytics, Osnabrueck University, D-49069 Osnabrueck, Germany
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5
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Yang J, Li Y, Qiu Q, Wang R, Yan W, Yu Y, Niu L, Pei H, Wei H, Ouyang L, Ye H, Xu D, Wei Y, Chen Q, Chen L. Small Molecules Promote Selective Denaturation and Degradation of Tubulin Heterodimers through a Low-Barrier Hydrogen Bond. J Med Chem 2022; 65:9159-9173. [PMID: 35762925 DOI: 10.1021/acs.jmedchem.2c00379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Here, we report a novel mechanism to selectively degrade target proteins. 3-(3-Phenoxybenzyl)amino-β-carboline (PAC), a tubulin inhibitor, promotes selective degradation of αβ-tubulin heterodimers. Biochemical studies have revealed that PAC specifically denatures tubulin, making it prone to aggregation that predisposes it to ubiquitinylation and then degradation. The degradation is mediated by a single hydrogen bond formed between the pyridine nitrogen of PAC and βGlu198, which is identified as a low-barrier hydrogen bond (LBHB). In contrast, another two tubulin inhibitors that only form normal hydrogen bonds with βGlu198 exhibit no degradation effect. Thus, the LBHB accounts for the degradation. We then screened for compounds capable of forming an LBHB with βGlu198 and demonstrated that BML284, a Wnt signaling activator, also promotes tubulin heterodimer degradation through the LBHB. Our study provided a unique example of LBHB function and identified a novel approach to obtain tubulin degraders.
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Affiliation(s)
- Jianhong Yang
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Yong Li
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Qiang Qiu
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Ruihan Wang
- MOE Key Laboratory of Green Chemistry and Technology, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Wei Yan
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Yamei Yu
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Lu Niu
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Heying Pei
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Haoche Wei
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Liang Ouyang
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Haoyu Ye
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Dingguo Xu
- MOE Key Laboratory of Green Chemistry and Technology, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China
| | - Yuquan Wei
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Qiang Chen
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
| | - Lijuan Chen
- Laboratory of Natural and Targeted Small Molecule Drugs, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu 610041, China
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Neutron crystallography reveals mechanisms used by Pseudomonas aeruginosa for host-cell binding. Nat Commun 2022; 13:194. [PMID: 35017516 PMCID: PMC8752737 DOI: 10.1038/s41467-021-27871-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/15/2021] [Indexed: 12/22/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa, a major cause of nosocomial infections, uses carbohydrate-binding proteins (lectins) as part of its binding to host cells. The fucose-binding lectin, LecB, displays a unique carbohydrate-binding site that incorporates two closely located calcium ions bridging between the ligand and protein, providing specificity and unusually high affinity. Here, we investigate the mechanisms involved in binding based on neutron crystallography studies of a fully deuterated LecB/fucose/calcium complex. The neutron structure, which includes the positions of all the hydrogen atoms, reveals that the high affinity of binding may be related to the occurrence of a low-barrier hydrogen bond induced by the proximity of the two calcium ions, the presence of coordination rings between the sugar, calcium and LecB, and the dynamic behaviour of bridging water molecules at room temperature. These key structural details may assist in the design of anti-adhesive compounds to combat multi-resistance bacterial infections. Pseudomonas aeruginosa employs lectins to bind to its host cells, and is known to be the major cause of lung infections. Lectin B (LecB) from Pseudomonas aeruginosa binds specifically to galactose and fucose and is important for pathogenicity, adhesion and biofilm formation. In this work, the neutron crystal structure (1.9 Å) of the deuterated LecB/Ca/fucose complex is reported. The structure, in combination with perdeuteration of the ligand and the receptor allowed the observation of hydrogen atoms, protonation states and hydrogen bonds involved in the interaction between pathogenic bacteria and host cells. Thus the study provides structural insights into the mechanism of high affinity binding of LecB to its targets.
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Chen Y, Wei W, Zhou Y, Xie D. The role of hydrogen bond in catalytic triad of serine proteases. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2110194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Yani Chen
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wanqing Wei
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yanzi Zhou
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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8
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Yoon S, Harris ME. Beyond the Plateau: pL Dependence of Proton Inventories as a Tool for Studying Ribozyme and Ribonuclease Catalysis. Biochemistry 2021; 60:2810-2823. [PMID: 34495648 DOI: 10.1021/acs.biochem.1c00489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acid/base catalysis is an important catalytic strategy used by ribonucleases and ribozymes; however, understanding the number and identity of functional groups involved in proton transfer remains challenging. The proton inventory (PI) technique analyzes the dependence of the enzyme reaction rate on the ratio of D2O to H2O and can provide information about the number of exchangeable sites that produce isotope effects and their magnitude. The Gross-Butler (GB) equation is used to evaluate H/D fractionation factors from PI data typically collected under conditions (i.e., a "plateau" in the pH-rate profile) assuming minimal change in active site residue ionization. However, restricting PI analysis to these conditions is problematic for many ribonucleases, ribozymes, and their variants due to ambiguity in the roles of active site residues, the lack of a plateau within the accessible pL range, or cooperative interactions between active site functional groups undergoing ionization. Here, we extend the integration of species distributions for alternative enzyme states in noncooperative models of acid/base catalysis into the GB equation, first used by Bevilacqua and colleagues for the HDV ribozyme, to develop a general population-weighted GB equation that allows simulation and global fitting of the three-dimensional relationship of the D2O ratio (n) versus pL versus kn/k0. Simulations using the GPW-GB equation of PI results for RNase A, HDVrz, and VSrz illustrate that data obtained at multiple selected pL values across the pL-rate profile can assist in the planning and interpreting of solvent isotope effect experiments to distinguish alternative mechanistic models.
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Affiliation(s)
- Suhyun Yoon
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
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9
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Mechanism of ArcLight derived GEVIs involves electrostatic interactions that can affect proton wires. Biophys J 2021; 120:1916-1926. [PMID: 33744263 PMCID: PMC8204334 DOI: 10.1016/j.bpj.2021.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/28/2021] [Accepted: 03/10/2021] [Indexed: 11/24/2022] Open
Abstract
The genetically encoded voltage indicators ArcLight and its derivatives mediate voltage-dependent optical signals by intermolecular, electrostatic interactions between neighboring fluorescent proteins (FPs). A random mutagenesis event placed a negative charge on the exterior of the FP, resulting in a greater than 10-fold improvement of the voltage-dependent optical signal. Repositioning this negative charge on the exterior of the FP reversed the polarity of voltage-dependent optical signals, suggesting the presence of “hot spots” capable of interacting with the negative charge on a neighboring FP, thereby changing the fluorescent output. To explore the potential effect on the chromophore state, voltage-clamp fluorometry was performed with alternating excitation at 390 nm followed by excitation at 470 nm, resulting in several mutants exhibiting voltage-dependent, ratiometric optical signals of opposing polarities. However, the kinetics, voltage ranges, and optimal FP fusion sites were different depending on the wavelength of excitation. These results suggest that the FP has external, electrostatic pathways capable of quenching fluorescence that are wavelength specific. One mutation to the FP (E222H) showed a voltage-dependent increase in fluorescence when excited at 390 nm, indicating the ability to affect the proton wire from the protonated chromophore to the H222 position. ArcLight-derived sensors may therefore offer a novel way to map how conditions external to the β-can structure can affect the fluorescence of the chromophore and transiently affect those pathways via conformational changes mediated by manipulating membrane potential.
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Kumar P, Agarwal PK, Cuneo MJ. On the Case of the Misplaced Hydrogens. Chembiochem 2021; 22:288-297. [PMID: 32706524 PMCID: PMC7952024 DOI: 10.1002/cbic.202000376] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/21/2020] [Indexed: 12/30/2022]
Abstract
Few other elements play a more central role in biology than hydrogen. The interactions, bonding and movement of hydrogen atoms are central to biological catalysis, structure and function. Yet owing to the elusive nature of a single hydrogen atom few experimental and computational techniques can precisely determine its location. This is exemplified in short hydrogen bonds (SHBs) where the location of the hydrogen atom is indicative of the underlying strength of the bonds, which can vary from 1-5 kcal/mol in canonical hydrogen bonds, to an almost covalent nature in single-well hydrogen bonds. Owing to the often-times inferred position of hydrogen, the role of SHBs in biology has remained highly contested and debated. This has also led to discrepancies in computational, biochemical and structural studies of proteins thought to use SHBs in performing chemistry and stabilizing interactions. Herein, we discuss in detail two distinct examples, namely the conserved catalytic triad and the photoreceptor, photoactive yellow protein, where studies of these SHB-containing systems have permitted contextualization of the role these unique hydrogen bonds play in biology.
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Affiliation(s)
- Prashasti Kumar
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Pratul K Agarwal
- Arium BioLabs LLC, Knoxville, TN, 37932, USA
- Department of Physiological Sciences and High-Performance Computing Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Matthew J Cuneo
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN, 38103, USA
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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: 24] [Impact Index Per Article: 8.0] [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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Abstract
The method to calculate the energy of intramolecular hydrogen bond is proposed and tested for a sample of malonaldehyde and its fluorine derivatives; the corresponding calculations were performed at the ωB97XD/aug-cc-pVTZ level. This method based on relationships found for related intermolecular hydrogen bonds is compared with other approaches which may be applied to estimate the intramolecular hydrogen bond energy. Particularly, methods based on the comparison of the system that contains the intramolecular hydrogen bond compared with corresponding conformations where such interaction does not occur are discussed. The function-based energy decomposition analysis, FB-EDA, of the intramolecular hydrogen bonds is also proposed here.
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13
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Inverse Solvent Isotope Effects in Enzyme-Catalyzed Reactions. Molecules 2020; 25:molecules25081933. [PMID: 32326332 PMCID: PMC7221790 DOI: 10.3390/molecules25081933] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 11/17/2022] Open
Abstract
Solvent isotope effects have long been used as a mechanistic tool for determining enzyme mechanisms. Most commonly, macroscopic rate constants such as kcat and kcat/Km are found to decrease when the reaction is performed in D2O for a variety of reasons including the transfer of protons. Under certain circumstances, these constants are found to increase, in what is termed an inverse solvent kinetic isotope effect (SKIE), which can be a diagnostic mechanistic feature. Generally, these phenomena can be attributed to an inverse solvent equilibrium isotope effect on a rapid equilibrium preceding the rate-limiting step(s). This review surveys inverse SKIEs in enzyme-catalyzed reactions by assessing their underlying origins in common mechanistic themes. Case studies for each category are presented, and the mechanistic implications are put into context. It is hoped that readers may find the illustrative examples valuable in planning and interpreting solvent isotope effect experiments.
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14
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Wu G. 17O NMR studies of organic and biological molecules in aqueous solution and in the solid state. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:135-191. [PMID: 31779879 DOI: 10.1016/j.pnmrs.2019.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 06/10/2023]
Abstract
This review describes the latest developments in the field of 17O NMR spectroscopy of organic and biological molecules both in aqueous solution and in the solid state. In the first part of the review, a general theoretical description of the nuclear quadrupole relaxation process in isotropic liquids is presented at a mathematical level suitable for non-specialists. In addition to the first-order quadrupole interaction, the theory also includes additional relaxation mechanisms such as the second-order quadrupole interaction and its cross correlation with shielding anisotropy. This complete theoretical treatment allows one to assess the transverse relaxation rate (thus the line width) of NMR signals from half-integer quadrupolar nuclei in solution over the entire range of motion. On the basis of this theoretical framework, we discuss general features of quadrupole-central-transition (QCT) NMR, which is a particularly powerful method of studying biomolecules in the slow motion regime. Then we review recent advances in 17O QCT NMR studies of biological macromolecules in aqueous solution. The second part of the review is concerned with solid-state 17O NMR studies of organic and biological molecules. As a sequel to the previous review on the same subject [G. Wu, Prog. Nucl. Magn. Reson. Spectrosc. 52 (2008) 118-169], the current review provides a complete coverage of the literature published since 2008 in this area.
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Affiliation(s)
- Gang Wu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada.
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15
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Vealey ZN, Foguel L, Vaccaro PH. Hydrogen-Bonding Motifs and Proton-Transfer Dynamics in Electronically Excited 6-Hydroxy-2-formylfulvene. J Phys Chem A 2019; 123:6506-6526. [DOI: 10.1021/acs.jpca.9b05025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary N. Vealey
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Lidor Foguel
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Patrick H. Vaccaro
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
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16
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Tolborg K, Jørgensen MRV, Sist M, Mamakhel A, Overgaard J, Iversen BB. Low‐Barrier Hydrogen Bonds in Negative Thermal Expansion Material H
3
[Co(CN)
6
]. Chemistry 2019; 25:6814-6822. [DOI: 10.1002/chem.201900358] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Kasper Tolborg
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Mads R. V. Jørgensen
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
- MAXIV LaboratoryLund University Fotongatan 2 22594 Lund Sweden
| | - Mattia Sist
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Aref Mamakhel
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Jacob Overgaard
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
| | - Bo B. Iversen
- Center for Materials CrystallographyDepartment of Chemistry and iNANOAarhus University Langelandsgade 140 8000 Aarhus C Denmark
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17
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Substrate binding mode and catalytic mechanism of human heparan sulfate d-glucuronyl C5 epimerase. Proc Natl Acad Sci U S A 2019; 116:6760-6765. [PMID: 30872481 DOI: 10.1073/pnas.1818333116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heparan sulfate (HS) is a linear, complex polysaccharide that modulates the biological activities of proteins through binding sites made by a series of Golgi-localized enzymes. Of these, glucuronyl C5-epimerase (Glce) catalyzes C5-epimerization of the HS component, d-glucuronic acid (GlcA), into l-iduronic acid (IdoA), which provides internal flexibility to the polymer and forges protein-binding sites to ensure polymer function. Here we report crystal structures of human Glce in the unbound state and of an inactive mutant, as assessed by real-time NMR spectroscopy, bound with a (GlcA-GlcNS)n substrate or a (IdoA-GlcNS)n product. Deep infiltration of the oligosaccharides into the active site cleft imposes a sharp kink within the central GlcNS-GlcA/IdoA-GlcNS trisaccharide motif. An extensive network of specific interactions illustrates the absolute requirement of N-sulfate groups vicinal to the epimerization site for substrate binding. At the epimerization site, the GlcA/IdoA rings are highly constrained in two closely related boat conformations, highlighting ring-puckering signatures during catalysis. The structure-based mechanism involves the two invariant acid/base residues, Glu499 and Tyr578, poised on each side of the target uronic acid residue, thus allowing reversible abstraction and readdition of a proton at the C5 position through a neutral enol intermediate, reminiscent of mandelate racemase. These structures also shed light on a convergent mechanism of action between HS epimerases and lyases and provide molecular frameworks for the chemoenzymatic synthesis of heparin or HS analogs.
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18
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Ni J, Pignatello JJ. Charge-assisted hydrogen bonding as a cohesive force in soil organic matter: water solubility enhancement by addition of simple carboxylic acids. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:1225-1233. [PMID: 30084855 DOI: 10.1039/c8em00255j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Weak bonds between molecular segments and between separate molecules of natural organic matter (OM) govern OM solubility, adsorption, supramolecular association in solution, and complexation with metal ions and oxides. We tested the hypothesis that especially strong hydrogen bonds, known as (negative) charge-assisted hydrogen bonds, (-)CAHB, contribute significantly to OM cohesion and play a role in the water solubility of solid-phase OM. The (-)CAHB, exemplified by structures such as (-CO2HO2C-)- and (-CO2HO-)-, may form between weak acids with similar proton affinity, and is shorter, more covalent, and much stronger than ordinary hydrogen bonds. Using a high-organic reference soil, we show that (-)CAHBs within the solid OM phase (intra-OM) are disrupted by solutions of aliphatic and aromatic acids, resulting in enhanced solubility of OM. The aromatic acids included naturally occurring plant exudate compounds. At constant pH and ionic strength, OM solubility increased with added organic acid concentration and molecular weight. Polar compounds incapable of forming (-)CAHBs, such as alkanols, acetonitrile, and dimethyl sulfoxide, were ineffective. Solubility enhancement showed behavior consistent with (-)CAHB theory and published observations-namely, (i) that formate is more effective than acetate due to its tendency to form stronger (-)CAHBs; (ii) that solubility enhancement peaks at pH ∼5-6, where the product of the concentration of the interacting carboxylate ions reaches a maximum; and (iii) that elution of acetate or formate through soil columns releases hydroxide ion, consistent with formation of (-)CAHBs between added acid and free weak acid groups on the solid OM. The results support the hypothesis that the (-)CAHB contributes to the cohesion of OM in the solid state.
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Affiliation(s)
- Jinzhi Ni
- Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, Connecticut 06504-1106, USA.
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19
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Vealey ZN, Foguel L, Vaccaro PH. Spectral Signatures of Proton-Transfer Dynamics at the Cusp of Low-Barrier Hydrogen Bonding. J Phys Chem Lett 2018; 9:4949-4954. [PMID: 30101590 DOI: 10.1021/acs.jpclett.8b02199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite their importance in diverse chemical and biochemical processes, low-barrier hydrogen bonds remain elusive targets to classify and interpret spectroscopically. Here the correlated nature of hydrogen bonding and proton transfer in the low-barrier regime has been probed for the ground and excited electronic states of 6-hydroxy-2-formylfulvene by acquiring jet-cooled fluorescence spectra of the parent and monodeuterated isotopologs. While excited-state profiles reveal regular vibronic patterns devoid of obvious dynamical signatures, their ground-state counterparts display a radically altered energy landscape characterized by spectral bifurcations comparable in magnitude to typical vibrational spacings (>100 cm-1). Quantitative analyses yield unusual deuterium kinetic isotope effects that straddle limiting values attributed to above-barrier vibration and below-barrier tunneling of the proton adjoining donor/acceptor sites. Our findings provide compelling experimental evidence for ultrafast hydron-migration events commensurate with the onset of low-barrier hydrogen bonding and afford a trenchant glimpse of molecular phenomena taking place at the "tipping point" between disparate dynamical regimes.
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Affiliation(s)
- Zachary N Vealey
- Department of Chemistry , Yale University , New Haven , Connecticut 06520-8107 United States
| | - Lidor Foguel
- Department of Chemistry , Yale University , New Haven , Connecticut 06520-8107 United States
| | - Patrick H Vaccaro
- Department of Chemistry , Yale University , New Haven , Connecticut 06520-8107 United States
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20
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Panek JJ, Jezierska A. N-oxide Derivatives: Car-Parrinello Molecular Dynamics and Electron Localization Function Study on Intramolecular Hydrogen Bonds. J Phys Chem A 2018; 122:6605-6614. [PMID: 30039968 DOI: 10.1021/acs.jpca.8b02970] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
First-principle molecular dynamics simulations (CPMD) and electron localization function (ELF) topological analysis were performed for two N-oxides, 2-[( N, N-dimethylamino- N-oxy)methyl]-4,6-dimethylphenol (I) and 5,5'-dibromo-3-[(diethylamino)methyl]-2,2'-biphenol N-oxide (II). Special attention was paid to hydrogen bond dynamics and spectroscopic features. Simulations were carried out in vacuo and in the crystalline phase. It was found that for compound I proton transfer phenomena do not occur spontaneously. An opposite situation was noticed for one of the two intramolecular hydrogen bonds of compound II. The influence of the neighboring molecules (including microsolvation) and the crystal field on the hydrogen bond properties cannot be neglected. Hydrogen bond spectroscopic signatures were quite well reproduced by power spectra of atomic velocity. Metric and spectroscopic theoretical findings were compared with experimental data available, especially in a view of the fact that experimental X-ray diffraction and FT-IR data of compound II indicate strong delocalization of the N-oxide bridge proton. ELF analysis showed that for compound II the N-oxide bridge belongs to the topological category of strong hydrogen bonds with the separate ELF basin for the bridged hydrogen atom.
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Affiliation(s)
- Jarosław J Panek
- Faculty of Chemistry , University of Wrocław , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Aneta Jezierska
- Faculty of Chemistry , University of Wrocław , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
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21
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Durlak P, Latajka Z. Car–Parrinello and Path Integral Molecular Dynamics Study of the Proton Transfer in the Intramolecular Hydrogen Bonds in the Ketohydrazone–Azoenol System. J Phys Chem B 2018; 122:7862-7873. [DOI: 10.1021/acs.jpcb.8b04883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Piotr Durlak
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie Street, 50-383 Wrocław, Poland
| | - Zdzisław Latajka
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie Street, 50-383 Wrocław, Poland
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22
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Lu J, Hung I, Brinkmann A, Gan Z, Kong X, Wu G. Solid-State 17 O NMR Reveals Hydrogen-Bonding Energetics: Not All Low-Barrier Hydrogen Bonds Are Strong. Angew Chem Int Ed Engl 2017; 56:6166-6170. [PMID: 28225158 DOI: 10.1002/anie.201700488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Indexed: 11/07/2022]
Abstract
While NMR and IR spectroscopic signatures and structural characteristics of low-barrier hydrogen bond (LBHB) formation are well documented in the literature, direct measurement of the LBHB energy is difficult. Here, we show that solid-state 17 O NMR spectroscopy can provide unique information about the energy required to break a LBHB. Our solid-state 17 O NMR data show that the HB enthalpy of the O⋅⋅⋅H⋅⋅⋅N LBHB formed in crystalline nicotinic acid is only 7.7±0.5 kcal mol-1 , suggesting that not all LBHBs are particularly strong.
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Affiliation(s)
- Jiasheng Lu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Andreas Brinkmann
- Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6, Canada
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Xianqi Kong
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Gang Wu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
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23
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Lu J, Hung I, Brinkmann A, Gan Z, Kong X, Wu G. Solid‐State
17
O NMR Reveals Hydrogen‐Bonding Energetics: Not All Low‐Barrier Hydrogen Bonds Are Strong. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700488] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jiasheng Lu
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance National High Magnetic Field Laboratory 1800 East Paul Dirac Drive Tallahassee FL 32310 USA
| | - Andreas Brinkmann
- Measurement Science and Standards National Research Council Canada 1200 Montreal Road Ottawa Ontario K1A 0R6 Canada
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance National High Magnetic Field Laboratory 1800 East Paul Dirac Drive Tallahassee FL 32310 USA
| | - Xianqi Kong
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Gang Wu
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
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24
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Lin J, Pozharski E, Wilson MA. Short Carboxylic Acid-Carboxylate Hydrogen Bonds Can Have Fully Localized Protons. Biochemistry 2017; 56:391-402. [PMID: 27989121 PMCID: PMC5805389 DOI: 10.1021/acs.biochem.6b00906] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Short hydrogen bonds (H-bonds) have been proposed to play key functional roles in several proteins. The location of the proton in short H-bonds is of central importance, as proton delocalization is a defining feature of low-barrier hydrogen bonds (LBHBs). Experimentally determining proton location in H-bonds is challenging. Here, bond length analysis of atomic (1.15-0.98 Å) resolution X-ray crystal structures of the human protein DJ-1 and its bacterial homologue, YajL, was used to determine the protonation states of H-bonded carboxylic acids. DJ-1 contains a buried, dimer-spanning 2.49 Å H-bond between Glu15 and Asp24 that satisfies standard donor-acceptor distance criteria for a LBHB. Bond length analysis indicates that the proton is localized on Asp24, excluding a LBHB at this location. However, similar analysis of the Escherichia coli homologue YajL shows both residues may be protonated at the H-bonded oxygen atoms, potentially consistent with a LBHB. A Protein Data Bank-wide screen identifies candidate carboxylic acid H-bonds in approximately 14% of proteins, which are typically short [⟨dO-O⟩ = 2.542(2) Å]. Chemically similar H-bonds between hydroxylated residues (Ser/Thr/Tyr) and carboxylates show a trend of lengthening O-O distance with increasing H-bond donor pKa. This trend suggests that conventional electronic effects provide an adequate explanation for short, charge-assisted carboxylic acid-carboxylate H-bonds in proteins, without the need to invoke LBHBs in general. This study demonstrates that bond length analysis of atomic resolution X-ray crystal structures provides a useful experimental test of certain candidate LBHBs.
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Affiliation(s)
- Jiusheng Lin
- Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, NE, 68588
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD, 21201,Institute for Bioscience and Biotechnology Research, Rockville, MD 20850,To whom correspondence can be addressed: Edwin Pozharski: or Mark A. Wilson:
| | - Mark A. Wilson
- Department of Biochemistry and the Redox Biology Center, University of Nebraska, Lincoln, NE, 68588,To whom correspondence can be addressed: Edwin Pozharski: or Mark A. Wilson:
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25
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Zilberg S, Dick B. Less stable tautomers form stronger hydrogen bonds: the case of water complexes. Phys Chem Chem Phys 2017; 19:25086-25094. [PMID: 28880041 DOI: 10.1039/c7cp04105e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hydrogen bonding in cyclic complexes of water with tautomeric pairs of molecules M0 and M1 is calculated to be stronger by more than 25% for the less stable tautomer M1 in all cases where the energy gap between the two tautomers is large (ΔE(M0 − M1) > 10 kcal mol−1).
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Affiliation(s)
- Shmuel Zilberg
- Chemical Sciences Department
- Ariel University
- Ariel 40700
- Israel
| | - Bernhard Dick
- Institute of Physical and Theoretical Chemistry
- University of Regensburg
- 93040 Regensburg
- Germany
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26
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Pagba CV, McCaslin TG, Chi SH, Perry JW, Barry BA. Proton-Coupled Electron Transfer and a Tyrosine-Histidine Pair in a Photosystem II-Inspired β-Hairpin Maquette: Kinetics on the Picosecond Time Scale. J Phys Chem B 2016; 120:1259-72. [PMID: 26886811 DOI: 10.1021/acs.jpcb.6b00560] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photosystem II (PSII) and ribonucleotide reductase employ oxidation and reduction of the tyrosine aromatic ring in radical transport pathways. Tyrosine-based reactions involve either proton-coupled electron transfer (PCET) or electron transfer (ET) alone, depending on the pH and the pKa of tyrosine's phenolic oxygen. In PSII, a subset of the PCET reactions are mediated by a tyrosine-histidine redox-driven proton relay, YD-His189. Peptide A is a PSII-inspired β-hairpin, which contains a single tyrosine (Y5) and histidine (H14). Previous electrochemical characterization indicated that Peptide A conducts a net PCET reaction between Y5 and H14, which have a cross-strand π-π interaction. The kinetic impact of H14 has not yet been explored. Here, we address this question through time-resolved absorption spectroscopy and 280-nm photolysis, which generates a neutral tyrosyl radical. The formation and decay of the neutral tyrosyl radical at 410 nm were monitored in Peptide A and its variant, Peptide C, in which H14 is replaced by cyclohexylalanine (Cha14). Significantly, both electron transfer (ET, pL 11, L = lyonium) and PCET (pL 9) were accelerated in Peptide A and C, compared to model tyrosinate or tyrosine at the same pL. Increased electronic coupling, mediated by the peptide backbone, can account for this rate acceleration. Deuterium exchange gave no significant solvent isotope effect in the peptides. At pL 9, but not at pL 11, the reaction rate decreased when H14 was mutated to Cha14. This decrease in rate is attributed to an increase in reorganization energy in the Cha14 mutant. The Y5-H14 mechanism in Peptide A is reminiscent of proton- and electron-transfer events involving YD-H189 in PSII. These results document a mechanism by which proton donors and acceptors can regulate the rate of PCET reactions.
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Affiliation(s)
- Cynthia V Pagba
- School of Chemistry and Biochemistry, the Petit Institute for Bioengineering and Bioscience, and the ‡Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Tyler G McCaslin
- School of Chemistry and Biochemistry, the Petit Institute for Bioengineering and Bioscience, and the ‡Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - San-Hui Chi
- School of Chemistry and Biochemistry, the Petit Institute for Bioengineering and Bioscience, and the ‡Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Joseph W Perry
- School of Chemistry and Biochemistry, the Petit Institute for Bioengineering and Bioscience, and the ‡Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Bridgette A Barry
- School of Chemistry and Biochemistry, the Petit Institute for Bioengineering and Bioscience, and the ‡Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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27
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Zilberg S, Dick B. Finding structural principles for strong hydrogen-bonds: Less stable tautomers form dimers with stronger hydrogen bonds. ChemistrySelect 2016. [DOI: 10.1002/slct.201600063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shmuel Zilberg
- Chemical Sciences Department; Ariel University; Ariel 40700 Israel
| | - Bernhard Dick
- Institute of Physical and Theoretical Chemistry; University of Regensburg; 93040 Regensburg Germany
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28
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Johnson NP, Ji H, Steinberg TH, von Hippel PH, Marcus AH. Sequence-Dependent Conformational Heterogeneity and Proton-Transfer Reactivity of the Fluorescent Guanine Analogue 6-Methyl Isoxanthopterin (6-MI) in DNA. J Phys Chem B 2015; 119:12798-807. [PMID: 26368400 DOI: 10.1021/acs.jpcb.5b06361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The local conformations of individual nucleic acid bases in DNA are important components in processes fundamental to gene regulation. Fluorescent nucleic acid base analogues, which can be substituted for natural bases in DNA, can serve as useful spectroscopic probes of average local base conformation and conformational heterogeneity. Here we report excitation-emission peak shift (EES) measurements of the fluorescent guanine (G) analogue 6-methyl isoxanthoptherin (6-MI), both as a ribonucleotide monophosphate (NMP) in solution and as a site-specific substituent for G in various DNA constructs. Changes in the peak positions of the fluorescence spectra as a function of excitation energy indicate that distinct subpopulations of conformational states exist in these samples on time scales longer than the fluorescence lifetime. Our pH-dependent measurements of the 6-MI NMP in solution show that these states can be identified as protonated and deprotonated forms of the 6-MI fluorescent probe. We implement a simple two-state model, which includes four vibrationally coupled electronic levels to estimate the free energy change, the free energy of activation, and the equilibrium constant for the proton transfer reaction. These parameters vary in single-stranded and duplex DNA constructs, and also depend on the sequence context of flanking bases. Our results suggest that proton transfer in 6-MI-substituted DNA constructs is coupled to conformational heterogeneity of the probe base, and can be interpreted to suggest that Watson-Crick base pairing between 6-MI and its complementary cytosine in duplex DNA involves a "low-barrier-hydrogen-bond". These findings may be important in using the 6-MI probe to understand local base conformational fluctuations, which likely play a central role in protein-DNA and ligand-DNA interactions.
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Affiliation(s)
- Neil P Johnson
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States.,Oregon Center for Optics and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States
| | - Huiying Ji
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States.,Oregon Center for Optics and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States
| | - Thomas H Steinberg
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States
| | - Peter H von Hippel
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States
| | - Andrew H Marcus
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States.,Oregon Center for Optics and Department of Chemistry and Biochemistry, University of Oregon , Eugene, Oregon 97403, United States
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29
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Affiliation(s)
- Perry Allen Frey
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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30
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Zarycz MNC, Provasi PF. Investigation of the resonance-assisted hydrogen bond in model β-diketones through localized molecular orbital analysis of the spin-spin coupling constants related to the O-H···O hydrogen bond. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:120-129. [PMID: 25266873 DOI: 10.1002/mrc.4152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 08/13/2014] [Accepted: 08/29/2014] [Indexed: 06/03/2023]
Abstract
The resonance-assisted hydrogen bond (HB) phenomenon has been studied theoretically by a localized molecular orbital (LMO) decomposition of the spin-spin coupling constants between atoms either involved or close to the O-H···O system of some β-diketones and their saturated counterparts. The analysis, carried out at the level of the second-order polarization propagator approximation, shows that the contributions in terms of LMO to the paramagnetic spin orbital and the spin dipolar Ramsey terms proof the importance of the delocalized π-electron structure supporting the idea of the existence of the resonance-assisted HB phenomenon phenomenon. The LMO contributions to the Fermi contact term indicate mainly the presence of the HB that may or not be linked to the π-electrons.
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Affiliation(s)
- M Natalia C Zarycz
- Department of Physics, University of Northeastern CONICET, Av. Libertad 5500, Corrientes, Argentina
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31
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Schmidtmann M, Middlemiss DS, Wilson CC. Isotopomeric polymorphism in a “doubly-polymorphic” multi-component molecular crystal. CrystEngComm 2015. [DOI: 10.1039/c5ce00123d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Isotopomeric polymorphism is observed in complexes of isonicotinamide with oxalic acid, highly unusual here in that each isotopic complex is itself polymorphic, a situation of “double polymorphism”. The four polymorphic forms exhibit different degrees of hydron transfer.
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Affiliation(s)
- Marc Schmidtmann
- Department of Chemistry
- Carl von Ossietzky University of Oldenburg
- Oldenburg, Germany
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32
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Kochanek SE, Clymer TM, Pakkala VS, Hebert SP, Reeping K, Firestine SM, Evanseck JD. Intramolecular charge-assisted hydrogen bond strength in pseudochair carboxyphosphate. J Phys Chem B 2014; 119:1184-91. [PMID: 25405523 PMCID: PMC4306500 DOI: 10.1021/jp506796r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Carboxyphosphate,
a suspected intermediate in ATP-dependent carboxylases,
has not been isolated nor observed directly by experiment. Consequently,
little is known concerning its structure, stability, and ionization
state. Recently, carboxyphosphate as either a monoanion or dianion
has been shown computationally to adopt a novel pseudochair conformation
featuring an intramolecular charge-assisted hydrogen bond (CAHB).
In this work, additive and subtractive correction schemes to the commonly
employed open–closed method are used to estimate the strength
of the CAHB. Truhlar’s Minnesota M06-2X functional with Dunning’s
aug-cc-pVTZ basis set has been used for geometry optimization, energy
evaluation, and frequency analysis. The CHARMM force field has been
used to approximate the Pauli repulsive terms in the closed and open
forms of carboxyphosphate. From our additive correction scheme, differential
Pauli repulsion contributions between the pseudochair (closed) and
open conformations of carboxyphosphate are found to be significant
in determining the CAHB strength. The additive correction modifies
the CAHB prediction (ΔEclosed–open) of −14 kcal/mol for the monoanion and −12 kcal/mol
for the dianion to −22.9 and −18.4 kcal/mol, respectively.
Results from the subtractive technique reinforce those from our additive
procedure, where the predicted CAHB strength ranges from −17.8
to −25.4 kcal/mol for the monoanion and from −15.7 to
−20.9 kcal/mol for the dianion. Ultimately, we find that the
CAHB in carboxyphosphate meets the criteria for short-strong hydrogen
bonds. However, carboxyphosphate has a unique energy profile that
does not result in the symmetric double-well behavior of low-barrier
hydrogen bonds. These findings provide deeper insight into the pseudochair
conformation of carboxyphosphate, and lead to an improved mechanistic
understanding of this intermediate in ATP-dependent carboxylases.
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Affiliation(s)
- Sarah E Kochanek
- Center for Computational Sciences and the Department of Chemistry and Biochemistry, Duquesne University , 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282-1530, United States
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33
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Natarajan A, Schwans JP, Herschlag D. Using unnatural amino acids to probe the energetics of oxyanion hole hydrogen bonds in the ketosteroid isomerase active site. J Am Chem Soc 2014; 136:7643-54. [PMID: 24787954 PMCID: PMC4046884 DOI: 10.1021/ja413174b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Indexed: 02/04/2023]
Abstract
Hydrogen bonds are ubiquitous in enzyme active sites, providing binding interactions and stabilizing charge rearrangements on substrate groups over the course of a reaction. But understanding the origin and magnitude of their catalytic contributions relative to hydrogen bonds made in aqueous solution remains difficult, in part because of complexities encountered in energetic interpretation of traditional site-directed mutagenesis experiments. It has been proposed for ketosteroid isomerase and other enzymes that active site hydrogen bonding groups provide energetic stabilization via "short, strong" or "low-barrier" hydrogen bonds that are formed due to matching of their pKa or proton affinity to that of the transition state. It has also been proposed that the ketosteroid isomerase and other enzyme active sites provide electrostatic environments that result in larger energetic responses (i.e., greater "sensitivity") to ground-state to transition-state charge rearrangement, relative to aqueous solution, thereby providing catalysis relative to the corresponding reaction in water. To test these models, we substituted tyrosine with fluorotyrosines (F-Tyr's) in the ketosteroid isomerase (KSI) oxyanion hole to systematically vary the proton affinity of an active site hydrogen bond donor while minimizing steric or structural effects. We found that a 40-fold increase in intrinsic F-Tyr acidity caused no significant change in activity for reactions with three different substrates. F-Tyr substitution did not change the solvent or primary kinetic isotope effect for proton abstraction, consistent with no change in mechanism arising from these substitutions. The observed shallow dependence of activity on the pKa of the substituted Tyr residues suggests that the KSI oxyanion hole does not provide catalysis by forming an energetically exceptional pKa-matched hydrogen bond. In addition, the shallow dependence provides no indication of an active site electrostatic environment that greatly enhances the energetic response to charge accumulation, consistent with prior experimental results.
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Affiliation(s)
- Aditya Natarajan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States
| | | | - Daniel Herschlag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, United States
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34
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Solomon EI, Heppner DE, Johnston EM, Ginsbach JW, Cirera J, Qayyum M, Kieber-Emmons MT, Kjaergaard CH, Hadt RG, Tian L. Copper active sites in biology. Chem Rev 2014; 114:3659-853. [PMID: 24588098 PMCID: PMC4040215 DOI: 10.1021/cr400327t] [Citation(s) in RCA: 1147] [Impact Index Per Article: 114.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - David E. Heppner
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | - Jake W. Ginsbach
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Jordi Cirera
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Munzarin Qayyum
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | | | - Ryan G. Hadt
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Li Tian
- Department of Chemistry, Stanford University, Stanford, CA, 94305
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35
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Nadal-Ferret M, Gelabert R, Moreno M, Lluch JM. Are there really low-barrier hydrogen bonds in proteins? The case of photoactive yellow protein. J Am Chem Soc 2014; 136:3542-52. [PMID: 24548066 DOI: 10.1021/ja4116617] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For a long time, low-barrier hydrogen bonds (LBHBs) have been proposed to exist in many enzymes and to play an important role in their catalytic function, but the proof of their existence has been elusive. The transient formation of an LBHB in a protein system has been detected for the first time using neutron diffraction techniques on a photoactive yellow protein (PYP) crystal in a study published in 2009 (Yamaguchi, S.; et al. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 440-444). However, very recent theoretical studies based on electronic structure calculations and NMR resonance experiments on PYP in solution (Saito, K.; et al. Proc. Natl. Acad. Sci. U.S.A. 2012, 109, 167-172) strongly indicate that there is not such an LBHB. By means of electronic structure calculations combined with the solution of the nuclear Schrödinger equation, we analyze here under which conditions an LBHB can exist in PYP, thus leading to a more reasonable and conciliating understanding of the above-mentioned studies.
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Affiliation(s)
- Marc Nadal-Ferret
- Departament de Química and ‡Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , 08193 Bellaterra (Barcelona), Spain
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36
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Kreuzer HW, Hill EA, Moran JJ, Bartholomew RA, Yang H, Hegg EL. Contributions of the [NiFe]- and [FeFe]-hydrogenase to H2production inShewanella oneidensisMR-1 as revealed by isotope ratio analysis of evolved H2. FEMS Microbiol Lett 2014; 352:18-24. [DOI: 10.1111/1574-6968.12361] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/06/2013] [Accepted: 12/14/2013] [Indexed: 11/29/2022] Open
Affiliation(s)
| | - Eric. A. Hill
- Pacific Northwest National Laboratory; Richland WA USA
| | | | | | - Hui Yang
- Michigan State University; East Lansing MI USA
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37
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Durlak P, Latajka Z. Car–Parrinello and path integral molecular dynamics study of the intramolecular hydrogen bonds in the crystals of benzoylacetone and dideuterobenzoylacetone. Phys Chem Chem Phys 2014; 16:23026-37. [DOI: 10.1039/c4cp02569e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of the intramolecular short hydrogen bond in the molecular crystal of benzoylacetone and its deuterated analogue are investigated using ab initio molecular dynamics simulations.
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Affiliation(s)
- Piotr Durlak
- Faculty of Chemistry
- University of Wrocław
- 50-383 Wrocław, Poland
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38
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Moynihan MM, Murkin AS. Cysteine Is the General Base That Serves in Catalysis by Isocitrate Lyase and in Mechanism-Based Inhibition by 3-Nitropropionate. Biochemistry 2013; 53:178-87. [DOI: 10.1021/bi401432t] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Margaret M. Moynihan
- Department
of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Andrew S. Murkin
- Department
of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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39
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Dong H, Fiorin G, DeGrado W, Klein ML. Exploring Histidine Conformations in the M2 Channel Lumen of the Influenza A Virus at Neutral pH via Molecular Simulations. J Phys Chem Lett 2013; 4:3067-3071. [PMID: 24069512 PMCID: PMC3779100 DOI: 10.1021/jz401672h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 08/28/2013] [Indexed: 06/02/2023]
Abstract
The pH-regulated M2 proton channel from the influenza A virus has a His-tetrad in its transmembrane (TM) domain that is essential for proton conduction. At neutral pH, the tetrad has been observed in two distinct configurations, the "His-box" and "dimer-of-dimers", with similar backbone structures suggesting competing models for proton conduction. Here, we propose that both conformations can play a role. In support of this hypothesis, we used molecular dynamics simulations based on density functional theory to simulate the M2-TM domain and force-field-based simulations to estimate the relevant free-energy barriers. Both configurations are stable on accessible simulation time scales, and transitions between them occur faster than the millisecond time scale of proton conduction. Moreover, the deprotonation energy is too high for spontaneous conduction, consistent with their occurrence in the low-current regime. Our computations support a multiconfiguration model with different population levels, thereby connecting experimental data obtained under different conditions.
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Affiliation(s)
- Hao Dong
- Institute for
Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122-6078, United States
| | - Giacomo Fiorin
- Institute for
Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122-6078, United States
| | - William
F. DeGrado
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 555 Mission Bay Boulevard South, San Francisco, California 94158-9001, United States
| | - Michael L. Klein
- Institute for
Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122-6078, United States
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40
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Oliveira BGD. Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H−δ⋯H+δdihydrogen bonds. Phys Chem Chem Phys 2013; 15:37-79. [DOI: 10.1039/c2cp41749a] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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41
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Shokri A, Abedin A, Fattahi A, Kass SR. Effect of Hydrogen Bonds on pKa Values: Importance of Networking. J Am Chem Soc 2012; 134:10646-50. [DOI: 10.1021/ja3037349] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alireza Shokri
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455,
United States
| | - Azardokht Abedin
- Department
of Chemistry, Sharif University of Technology, Tehran, Iran
| | - Alireza Fattahi
- Department
of Chemistry, Sharif University of Technology, Tehran, Iran
| | - Steven R. Kass
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455,
United States
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42
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Raissi H, Yoosefian M, Khoshkhou S. Conformational study of the (z)-[(2-iminoethylidone)silyl]amine at the MP2, DFT and G2MP2 levels. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Nanubolu JB, Sridhar B, Ravikumar K. Resonance-assisted amide protonation in dutasteride hydrochloride salt. CrystEngComm 2012. [DOI: 10.1039/c2ce06421a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Isaev AN. On the question of hydrogen bond proton transfer. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2011. [DOI: 10.1134/s0036024412010128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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45
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JALILI SEIFOLLAH, AKHAVAN MOJDEH. STUDY OF INTRAMOLECULAR HYDROGEN BONDING IN ORTHO-SUBSTITUTED ACETANILIDE COMPOUNDS USING COMPUTATIONAL METHODS. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633604001185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The intramolecular hydrogen bonding formation in ortho-substituted compounds of Acetanilide, ortho-hydroxy Acetanilide and ortho-nitro Acetanilide, was investigated using Density Functional Theory (DFT), Møller-Plesset second-order (MP2) method and "Atoms in Molecules (AIM)" theory. It was found that in each case, the cis isomer is more stable than the trans isomer and ortho-nitro Acetanilide forms a stronger hydrogen bond than ortho-hydroxy Acetanilide. The effects of hydrogen bonding on structural parameters of the considered systems were studied using Becke's functional (B3LYP) and at the ab initio MP2 level in conjunction with different basis sets and suitable structural factors. The results are in agreement with the results of AIM theory.
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Affiliation(s)
- SEIFOLLAH JALILI
- Department of Chemistry, K. N. Toosi University of Technology, P. O. Box 15875-4416, Tehran, Iran
- Department of Nano-Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), P. O. Box 19395-5531, Tehran, Iran
| | - MOJDEH AKHAVAN
- Department of Chemistry, K. N. Toosi University of Technology, P. O. Box 15875-4416, Tehran, Iran
- Department of Nano-Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), P. O. Box 19395-5531, Tehran, Iran
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46
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Liu M, Kang S, Ray S, Jackson J, Zaitsev AD, Gerber SA, Cuny GD, Glicksman MA. Kinetic, mechanistic, and structural modeling studies of truncated wild-type leucine-rich repeat kinase 2 and the G2019S mutant. Biochemistry 2011; 50:9399-408. [PMID: 21961647 DOI: 10.1021/bi201173d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Leucine-rich repeat kinase 2 (LRRK2), a large and complex protein that possesses two enzymatic properties, kinase and GTPase, is one of the major genetic factors in Parkinson's disease (PD). Here, we characterize the kinetic and catalytic mechanisms of truncated wild-type (t-wt) LRRK2 and its most common mutant, G2019S (t-G2019S), with a structural interpretation of the kinase domain. First, the substitution of threonine with serine in the LRRKtide peptide results in a much less efficient substrate as demonstrated by a 26-fold decrease in k(cat) and a 6-fold decrease in binding affinity. The significant decrease in k(cat) is attributed to a slow chemical transfer step as evidenced by the inverse solvent kinetic isotope effect in the proton inventory and pL (pH or pD)-dependent studies. The shape of the proton inventory and pL profile clearly signals the involvement of a general base (pK(a) = 7.5) in the catalysis with a low fractionation factor in the ground state. We report for the first time that the increased kinase activity of the G2019S mutant is substrate-dependent. Homology modeling of the kinase domain (open and closed forms) and structural analysis of the docked peptide substrates suggest that electrostatic interactions play an important role in substrate recognition, which is affected by G2019S and may directly influence the kinetic properties of the enzyme. Finally, the GTPase activity of the t-G2019S mutant was characterized, and the mutation modestly decreases GTPase activity without significantly affecting GTP binding affinity.
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Affiliation(s)
- Min Liu
- Laboratory for Drug Discovery in Neurodegeneration, Harvard NeuroDiscovery Center, Brigham and Women's Hospital, Harvard Medical School, Cambridge, Massachusetts 02139, United States.
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47
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Keough JM, Jenson DL, Zuniga AN, Barry BA. Proton coupled electron transfer and redox-active tyrosine Z in the photosynthetic oxygen-evolving complex. J Am Chem Soc 2011; 133:11084-7. [PMID: 21714528 PMCID: PMC3246746 DOI: 10.1021/ja2041139] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proton coupled electron transfer (PCET) reactions play an essential role in many enzymatic processes. In PCET, redox-active tyrosines may be involved as intermediates when the oxidized phenolic side chain deprotonates. Photosystem II (PSII) is an excellent framework for studying PCET reactions, because it contains two redox-active tyrosines, YD and YZ, with different roles in catalysis. One of the redox-active tyrosines, YZ, is essential for oxygen evolution and is rapidly reduced by the manganese-catalytic site. In this report, we investigate the mechanism of YZ PCET in oxygen-evolving PSII. To isolate YZ(•) reactions, but retain the manganese-calcium cluster, low temperatures were used to block the oxidation of the metal cluster, high microwave powers were used to saturate the YD(•) EPR signal, and YZ(•) decay kinetics were measured with EPR spectroscopy. Analysis of the pH and solvent isotope dependence was performed. The rate of YZ(•) decay exhibited a significant solvent isotope effect, and the rate of recombination and the solvent isotope effect were pH independent from pH 5.0 to 7.5. These results are consistent with a rate-limiting, coupled proton electron transfer (CPET) reaction and are contrasted to results obtained for YD(•) decay kinetics at low pH. This effect may be mediated by an extensive hydrogen-bond network around YZ. These experiments imply that PCET reactions distinguish the two PSII redox-active tyrosines.
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Affiliation(s)
- James M. Keough
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - David L. Jenson
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Ashley N. Zuniga
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Bridgette A. Barry
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
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48
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Hall RS, Fedorov AA, Xu C, Fedorov EV, Almo SC, Raushel FM. Three-dimensional structure and catalytic mechanism of cytosine deaminase. Biochemistry 2011; 50:5077-85. [PMID: 21545144 DOI: 10.1021/bi200483k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytosine deaminase (CDA) from E. coli is a member of the amidohydrolase superfamily. The structure of the zinc-activated enzyme was determined in the presence of phosphonocytosine, a mimic of the tetrahedral reaction intermediate. This compound inhibits the deamination of cytosine with a K(i) of 52 nM. The zinc- and iron-containing enzymes were characterized to determine the effect of the divalent cations on activation of the hydrolytic water. Fe-CDA loses activity at low pH with a kinetic pK(a) of 6.0, and Zn-CDA has a kinetic pK(a) of 7.3. Mutation of Gln-156 decreased the catalytic activity by more than 5 orders of magnitude, supporting its role in substrate binding. Mutation of Glu-217, Asp-313, and His-246 significantly decreased catalytic activity supporting the role of these three residues in activation of the hydrolytic water molecule and facilitation of proton transfer reactions. A library of potential substrates was used to probe the structural determinants responsible for catalytic activity. CDA was able to catalyze the deamination of isocytosine and the hydrolysis of 3-oxauracil. Large inverse solvent isotope effects were obtained on k(cat) and k(cat)/K(m), consistent with the formation of a low-barrier hydrogen bond during the conversion of cytosine to uracil. A chemical mechanism for substrate deamination by CDA was proposed.
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Affiliation(s)
- Richard S Hall
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
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49
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Yi P, Peng H, Wang Z, Yu X, Li X, Liang Y. Theoretical Study of Structure, Energetic, Hydrogen Bonds Strength and Intramolecular Proton Transfer of 2-(2-R (ROH, NH2, SH) Phenyl (or Pyridyl)) Benzoxazoles (or Benzothiazoles). CHINESE J CHEM 2011. [DOI: 10.1002/cjoc.201190136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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50
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Biliškov N, Kojić-Prodić B, Mali G, Molčanov K, Stare J. A Partial Proton Transfer in Hydrogen Bond O−H···O in Crystals of Anhydrous Potassium and Rubidium Complex Chloranilates. J Phys Chem A 2011; 115:3154-66. [DOI: 10.1021/jp112380f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Nikola Biliškov
- Rudjer Bošković Institute, POB 180, HR-10002 Zagreb, Croatia
| | | | - Gregor Mali
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Dunajska c. 156, SI-1000 Ljubljana
| | | | - Jernej Stare
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
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