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Dixit VA, Murty US, Bajaj P, Blumberger J, de Visser SP. Mechanisms of Electron Transfer Rate Modulations in Cytochrome P450 BM3. J Phys Chem B 2022; 126:9737-9747. [PMID: 36384294 DOI: 10.1021/acs.jpcb.2c03967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial cytochromes P450 BM3 (CYP450 BM3) catalyze reactions of industrial importance. Despite many successful biotransformations, robust (re)design for novel applications remains challenging. Rational design and evolutionary approaches are not always successful, highlighting a lack of complete understanding of the mechanisms of electron transfer (ET) modulations. Thus, the full potential of CYP450 reactions remains under-exploited. In this work, we report the first molecular dynamics (MD)-based explicit prediction of BM3 ET parameters (reorganization energies; λ and ET free energies; ΔG°), and log ET rates (log kET) using the Marcus theory. Overall, the calculated ET rates for the BM3 wild-type (WT), mutants (F393 and L86), ligand-bound state, and ion concentrations agree well with experimental data. In ligand-free (LF) BM3, mutations modulate kET via ET ΔG°. Simulations show that the experimental ET rate enhancement is due to increased driving force (more negative ΔG°) upon ligation. This increase is related to the protein reorganization required to accommodate the ligand in the binding pocket rather than binding interactions with the ligand. Our methodology (CYPWare 1.0) automates all the stages of the MD simulation step-up, energy calculations, and estimation of ET parameters. CYPWare 1.0 and this work thus represent an important advancement in the CYP450 ET rate predictions, which has the potential to guide the redesign of ET enzymes. This program and a Web tool are available on GitHub for academic research.
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Affiliation(s)
- Vaibhav A Dixit
- Department of Medicinal Chemistry, Department of Pharmaceuticals, Ministry of Chemicals & Fertilizers,, National Institute of Pharmaceutical Education and Research, Guwahati, (NIPER Guwahati) Govt. of India, Sila Katamur (Halugurisuk), P.O.: Changsari, Dist: Kamrup, 781101Guwahati, Assam, India
| | - Upadhyayula Suryanarayana Murty
- Department of Medicinal Chemistry, Department of Pharmaceuticals, Ministry of Chemicals & Fertilizers,, National Institute of Pharmaceutical Education and Research, Guwahati, (NIPER Guwahati) Govt. of India, Sila Katamur (Halugurisuk), P.O.: Changsari, Dist: Kamrup, 781101Guwahati, Assam, India
| | - Priyanka Bajaj
- National Institute of Pharmaceutical Education and Research, Hyderabad (NIPER Hyderabad), NH-9, Balanagar Main Road, Kukatpally Industrial Estate, Balanagar, Hyderabad500037, Telangana, India
| | - Jochen Blumberger
- Department of Physics and Astronomy, and Thomas Young Centre, University College London, Gower Street, LondonWC1E 6BT, U.K
| | - Sam P de Visser
- Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, ManchesterM17DN, U.K
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2
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Luirink RA, Dekker SJ, Capoferri L, Janssen LF, Kuiper CL, Ari ME, Vermeulen NP, Vos JC, Commandeur JN, Geerke DP. A combined computational and experimental study on selective flucloxacillin hydroxylation by cytochrome P450 BM3 variants. J Inorg Biochem 2018; 184:115-122. [DOI: 10.1016/j.jinorgbio.2018.04.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 03/23/2018] [Accepted: 04/18/2018] [Indexed: 12/20/2022]
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3
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Capoferri L, Leth R, ter Haar E, Mohanty AK, Grootenhuis PDJ, Vottero E, Commandeur JNM, Vermeulen NPE, Jørgensen FS, Olsen L, Geerke DP. Insights into regioselective metabolism of mefenamic acid by cytochrome P450 BM3 mutants through crystallography, docking, molecular dynamics, and free energy calculations. Proteins 2016; 84:383-96. [PMID: 26757175 DOI: 10.1002/prot.24985] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 12/21/2022]
Abstract
Cytochrome P450 BM3 (CYP102A1) mutant M11 is able to metabolize a wide range of drugs and drug-like compounds. Among these, M11 was recently found to be able to catalyze formation of human metabolites of mefenamic acid and other nonsteroidal anti-inflammatory drugs (NSAIDs). Interestingly, single active-site mutations such as V87I were reported to invert regioselectivity in NSAID hydroxylation. In this work, we combine crystallography and molecular simulation to study the effect of single mutations on binding and regioselective metabolism of mefenamic acid by M11 mutants. The heme domain of the protein mutant M11 was expressed, purified, and crystallized, and its X-ray structure was used as template for modeling. A multistep approach was used that combines molecular docking, molecular dynamics (MD) simulation, and binding free-energy calculations to address protein flexibility. In this way, preferred binding modes that are consistent with oxidation at the experimentally observed sites of metabolism (SOMs) were identified. Whereas docking could not be used to retrospectively predict experimental trends in regioselectivity, we were able to rank binding modes in line with the preferred SOMs of mefenamic acid by M11 and its mutants by including protein flexibility and dynamics in free-energy computation. In addition, we could obtain structural insights into the change in regioselectivity of mefenamic acid hydroxylation due to single active-site mutations. Our findings confirm that use of MD and binding free-energy calculation is useful for studying biocatalysis in those cases in which enzyme binding is a critical event in determining the selective metabolism of a substrate.
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Affiliation(s)
- Luigi Capoferri
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands
| | - Rasmus Leth
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Ernst ter Haar
- Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA, 02210
| | - Arun K Mohanty
- Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA, 02210
| | | | - Eduardo Vottero
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands
| | - Jan N M Commandeur
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands
| | - Nico P E Vermeulen
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands
| | - Flemming Steen Jørgensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Lars Olsen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Daan P Geerke
- AIMMS Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical Sciences, VU University, De Boelelaan 1083, 1081 HV Amsterdam, the Netherlands
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Litzenburger M, Bernhardt R. Selective oxidation of carotenoid-derived aroma compounds by CYP260B1 and CYP267B1 from Sorangium cellulosum So ce56. Appl Microbiol Biotechnol 2016; 100:4447-57. [PMID: 26767988 DOI: 10.1007/s00253-015-7269-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/17/2015] [Accepted: 12/23/2015] [Indexed: 11/24/2022]
Abstract
Due to their bioactive properties as well as their application as precursors in chemical synthesis, hydroxylated isoprenoids and norisoprenoids are very valuable compounds. The efficient hydroxylation of such compounds remains a challenge in organic chemistry caused by the formation of a variety of side products and lack of overall regio- and stereoselectivity. In contrast, cytochromes P450 are known for their selective oxidation under mild conditions. Here, we demonstrate for the first time the ability of myxobacterial CYP260B1 and CYP267B1 from Sorangium cellulosum So ce56 to oxidize such carotenoid-derived aroma compounds. A focused library of 14 substrates such as ionones, damascones, as well as some of their isomers and derivatives was screened in vitro. Both P450s were capable of an efficient oxidation of all tested compounds. CYP260B1-dependent conversions mainly formed multiple products, whereas conversions by CYP267B1 resulted predominantly in a single product. To identify the main products by NMR spectroscopy, an Escherichia coli-based whole-cell system was used. CYP267B1 showed a hydroxylase activity towards the formation of allylic alcohols. Likewise, CYP260B1 performed the allylic hydroxylation of β-damascone [(E)-1-(2,6,6-trimethylcyclohex-1-enyl)but-2-en-1-one] and δ-damascone [(E)-1-(2,6,6-trimethylcyclohex-3-enyl)but-2-en-1-one]. Moreover, CYP260B1 showed an epoxidase activity towards β-ionone [(E)-4-(2,6,6-trimethylcyclohex-1-enyl)but-3-en-2-one] as well as the methyl-substituted α-ionone derivatives raldeine [(E)-1-(2,6,6-trimethylcyclohex-2-enyl)pent-1-en-3-one] and isoraldeine [(E)-3-methyl-4-(2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one]. In addition, to known products, also novel products such as 2-OH-δ-damascone [(E)-1-(5-hydroxy-2,6,6-trimethylcyclohex-3-enyl)but-2-en-1-one], 3-OH-allyl-α-ionone [(E)-1-(4-hydroxy-2,6,6-trimethylcyclohex-2-enyl)hepta-1,6-dien-3-one], and 4-OH-allyl-β-ionone [(E)-1-(3-hydroxy-2,6,6-trimethylcyclohex-1-enyl)hepta-1,6-dien-3-one] were identified during our studies.
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Affiliation(s)
- Martin Litzenburger
- Institut für Biochemie, Universität des Saarlandes, Campus B.2.2, 66123, Saarbruecken, Germany
| | - Rita Bernhardt
- Institut für Biochemie, Universität des Saarlandes, Campus B.2.2, 66123, Saarbruecken, Germany.
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Olsen L, Oostenbrink C, Jørgensen FS. Prediction of cytochrome P450 mediated metabolism. Adv Drug Deliv Rev 2015; 86:61-71. [PMID: 25958010 DOI: 10.1016/j.addr.2015.04.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 03/30/2015] [Accepted: 04/27/2015] [Indexed: 10/23/2022]
Abstract
Cytochrome P450 enzymes (CYPs) form one of the most important enzyme families involved in the metabolism of xenobiotics. CYPs comprise many isoforms, which catalyze a wide variety of reactions, and potentially, a large number of different metabolites can be formed. However, it is often hard to rationalize what metabolites these enzymes generate. In recent years, many different in silico approaches have been developed to predict binding or regioselective product formation for the different CYP isoforms. These comprise ligand-based methods that are trained on experimental CYP data and structure-based methods that consider how the substrate is oriented in the active site or/and how reactive the part of the substrate that is accessible to the heme group is. We will review key aspects for various approaches that are available to predict binding and site of metabolism (SOM), what outcome can be expected from the predictions, and how they could potentially be improved.
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Abstract
Drug metabolism can produce metabolites with physicochemical and pharmacological properties that differ substantially from those of the parent drug, and consequently has important implications for both drug safety and efficacy. To reduce the risk of costly clinical-stage attrition due to the metabolic characteristics of drug candidates, there is a need for efficient and reliable ways to predict drug metabolism in vitro, in silico and in vivo. In this Perspective, we provide an overview of the state of the art of experimental and computational approaches for investigating drug metabolism. We highlight the scope and limitations of these methods, and indicate strategies to harvest the synergies that result from combining measurement and prediction of drug metabolism.
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Pyranose dehydrogenase ligand promiscuity: a generalized approach to simulate monosaccharide solvation, binding, and product formation. PLoS Comput Biol 2014; 10:e1003995. [PMID: 25500811 PMCID: PMC4263366 DOI: 10.1371/journal.pcbi.1003995] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 10/13/2014] [Indexed: 11/19/2022] Open
Abstract
The flavoenzyme pyranose dehydrogenase (PDH) from the litter decomposing fungus Agaricus meleagris oxidizes many different carbohydrates occurring during lignin degradation. This promiscuous substrate specificity makes PDH a promising catalyst for bioelectrochemical applications. A generalized approach to simulate all 32 possible aldohexopyranoses in the course of one or a few molecular dynamics (MD) simulations is reported. Free energy calculations according to the one-step perturbation (OSP) method revealed the solvation free energies (ΔGsolv) of all 32 aldohexopyranoses in water, which have not yet been reported in the literature. The free energy difference between β- and α-anomers (ΔGβ-α) of all d-stereoisomers in water were compared to experimental values with a good agreement. Moreover, the free-energy differences (ΔG) of the 32 stereoisomers bound to PDH in two different poses were calculated from MD simulations. The relative binding free energies (ΔΔGbind) were calculated and, where available, compared to experimental values, approximated from Km values. The agreement was very good for one of the poses, in which the sugars are positioned in the active site for oxidation at C1 or C2. Distance analysis between hydrogens of the monosaccharide and the reactive N5-atom of the flavin adenine dinucleotide (FAD) revealed that oxidation is possible at HC1 or HC2 for pose A, and at HC3 or HC4 for pose B. Experimentally detected oxidation products could be rationalized for the majority of monosaccharides by combining ΔΔGbind and a reweighted distance analysis. Furthermore, several oxidation products were predicted for sugars that have not yet been tested experimentally, directing further analyses. This study rationalizes the relationship between binding free energies and substrate promiscuity in PDH, providing novel insights for its applicability in bioelectrochemistry. The results suggest that a similar approach could be applied to study promiscuity of other enzymes. Generally, enzymes are perceived as being specific for both their substrates and the reaction they catalyze. This standard paradigm started to shift and currently enzyme promiscuity towards various substrates is perceived rather as the rule than the exception. Enzyme promiscuity seems to be vital for proteins to acquire new functions, and therefore for evolution itself. The driving forces for promiscuity are manifold and consequently challenging to study. Binding free energies, which can be calculated from computer simulations, represent a convenient measure for them. Here, we investigate the binding free energies between the enzyme pyranose dehydrogenase (PDH) and a sugar-substrate by computational means. PDH has an extraordinarily promiscuous substrate-specificity, making it interesting for e.g. bioelectrochemical applications. By introducing modifications to the sugar-structure used for the molecular dynamics simulations, we could simultaneously study all 32 possible aldohexopyranoses from a single simulation. This saves costly computational resources and time for setting up and analyzing the simulations. We could nicely reproduce experimental results and predict so far undetected sugar-oxidation products, directing further experiments. This study gives novel insights into PDH's substrate promiscuity and the enzyme's applicability. A similar approach could be applied to study the promiscuity of other enzymes.
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Meneghini C, Leboffe L, Bionducci M, Fanali G, Meli M, Colombo G, Fasano M, Ascenzi P, Mobilio S. The five-to-six-coordination transition of ferric human serum heme-albumin is allosterically-modulated by ibuprofen and warfarin: a combined XAS and MD study. PLoS One 2014; 9:e104231. [PMID: 25153171 PMCID: PMC4143227 DOI: 10.1371/journal.pone.0104231] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 07/08/2014] [Indexed: 12/20/2022] Open
Abstract
Human serum albumin (HSA) is involved physiologically in heme scavenging; in turn, heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, the allosteric effect of ibuprofen and warfarin on the local atomic structure around the ferric heme-Fe (heme-Fe(III)) atom of HSA-heme-Fe (HSA-heme-Fe(III)) has been probed by Fe-K edge X-ray absorption spectroscopy (XAS). The quantitative analysis of the Fe-K edge extended X-ray absorption fine structure (EXAFS) signals and modeling of the near edge (XANES) spectral features demonstrated that warfarin and ibuprofen binding modify the local structure of the heme-Fe(III). Combined XAS data analysis and targeted molecular dynamics (MD) simulations provided atomic resolution insights of protein structural rearrangements required to accommodate the heme-Fe(III) upon ibuprofen and warfarin binding. In the absence of drugs, the heme-Fe(III) atom is penta-coordinated having distorted 4+1 configuration made by the nitrogen atoms of the porphyrin ring and the oxygen phenoxy atom of the Tyr161 residue. MD simulations show that ibuprofen and warfarin association to the secondary fatty acid (FA) binding site 2 (FA2) induces a reorientation of domain I of HSA-heme-Fe(III), this leads to the redirection of the His146 residue providing an additional bond to the heme-Fe(III) atom, providing the 5+1 configuration. The comparison of Fe-K edge XANES spectra calculated using MD structures with those obtained experimentally confirms the reliability of the proposed structural model. As a whole, combining XAS and MD simulations it has been possible to provide a reliable model of the heme-Fe(III) atom coordination state and to understand the complex allosteric transition occurring in HSA-heme-Fe(III) upon ibuprofen and warfarin binding.
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Affiliation(s)
| | - Loris Leboffe
- Department of Sciences, Roma Tre University, Roma, Italy
- National Institute of Biostructures and Biosystems, Roma, Italy
| | | | - Gabriella Fanali
- Biomedical Research Division, Department of Theoretical and Applied Sciences, and Center of Neuroscience, University of Insubria, Busto Arsizio (VA), Italy
| | - Massimiliano Meli
- Institute for Molecular Recognition Chemistry, National Research Council, Milano, Italy
| | - Giorgio Colombo
- Institute for Molecular Recognition Chemistry, National Research Council, Milano, Italy
| | - Mauro Fasano
- Biomedical Research Division, Department of Theoretical and Applied Sciences, and Center of Neuroscience, University of Insubria, Busto Arsizio (VA), Italy
| | - Paolo Ascenzi
- National Institute of Biostructures and Biosystems, Roma, Italy
- Interdepartmental Laboratory of Electron Microscopy, Roma Tre University, Roma, Italy
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Oostenbrink C. Structure‐Based Methods for Predicting the Sites and Products of Metabolism. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/9783527673261.ch10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Plazinska A, Plazinski W, Jozwiak K. Fast, metadynamics-based method for prediction of the stereochemistry-dependent relative free energies of ligand-receptor interactions. J Comput Chem 2014; 35:876-82. [PMID: 24615679 DOI: 10.1002/jcc.23563] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/30/2014] [Accepted: 02/01/2014] [Indexed: 01/09/2023]
Abstract
The computational approach applicable for the molecular dynamics (MD)-based techniques is proposed to predict the ligand-protein binding affinities dependent on the ligand stereochemistry. All possible stereoconfigurations are expressed in terms of one set of force-field parameters [stereoconfiguration-independent potential (SIP)], which allows for calculating all relative free energies by only single simulation. SIP can be used for studying diverse, stereoconfiguration-dependent phenomena by means of various computational techniques of enhanced sampling. The method has been successfully tested on the β2-adrenergic receptor (β2-AR) binding the four fenoterol stereoisomers by both metadynamics simulations and replica-exchange MD. Both the methods gave very similar results, fully confirming the presence of stereoselective effects in the fenoterol-β2-AR interactions. However, the metadynamics-based approach offered much better efficiency of sampling which allows for significant reduction of the unphysical region in SIP.
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Affiliation(s)
- Anita Plazinska
- Department of Chemistry, Faculty of Pharmacy, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, W. Chodzki Street, 4a, 20-093, Lublin, Poland
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Lai B, Nagy G, Garate JA, Oostenbrink C. Entropic and enthalpic contributions to stereospecific ligand binding from enhanced sampling methods. J Chem Inf Model 2014; 54:151-8. [PMID: 24372516 PMCID: PMC3904767 DOI: 10.1021/ci4006657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
The
stereoselective binding of R- and S-propranolol to the metabolic enzyme cytochrome P450 2D6
and its mutant F483A was studied using various computational approaches.
Previously reported free-energy differences from Hamiltonian replica
exchange simulations, combined with thermodynamic integration, are
compared to the one-step perturbation approach, combined with local-elevation
enhanced sampling, and an excellent agreement between methods was
obtained. Further, the free-energy differences are interpreted in
terms of enthalpic and entropic contributions where it is shown that
exactly compensating contributions obscure a molecular interpretation
of differences in the affinity while various reduced terms allow a
more detailed analysis, which agree with heuristic observations on
the interactions.
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Affiliation(s)
- Balder Lai
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation at BOKU- University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
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Lin Z, van Gunsteren WF. Influence of variation of a side chain on the folding equilibrium of a β-peptide: limitations of one-step perturbation. J Comput Chem 2013; 34:1899-906. [PMID: 23712925 DOI: 10.1002/jcc.23331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 04/25/2013] [Indexed: 11/11/2022]
Abstract
In a recent study (Lin et al., Helv. Chim. Acta 2011, 94, 597), the one-step perturbation method was applied to tackle a challenging computational problem, that is, the calculation of the folding free enthalpies ΔGF,U of six hepta-β-peptides with different, Ala, Val, Leu, Ile, Ser, or Thr, side chains in the fifth residue. The ΔGF,U values obtained using one-step perturbation based on a single molecular dynamics simulation of a judiciously chosen reference state with soft-core atoms in the side chain of the fifth residue showed an overall accuracy of about kB T for the four peptides with nonpolar side chains, but twice as large deviations were observed for the peptides with polar side chains. Here, alternative reference-state Hamiltonians that better cover the conformational space relevant to these peptides are investigated, and post simulation rotational sampling of the χ1 and χ2 torsional angles of the fifth residue is carried out to sample different orientations of the side chain. A reference state with rather soft atoms yields accurate ΔGF,U values for the peptides with the Ser and Thr side chains, but it failed to correctly predict the folding free enthalpy for one peptide with a nonpolar side chain, that is, Leu. Based on the results and those of earlier studies, possible ways to improve the accuracy of the efficient one-step perturbation technique to compute free enthalpies of folding are discussed.
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Affiliation(s)
- Zhixiong Lin
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093 Zürich, Switzerland
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