Role of Inhibitor Aliphatic Chain in the Thermodynamics of Inhibitor Binding to Escherichia coli Enoyl-ACP Reductase and the Phe203Leu Mutant: A Proposed Mechanism for Drug Resistance
| العنوان: | Role of Inhibitor Aliphatic Chain in the Thermodynamics of Inhibitor Binding to Escherichia coli Enoyl-ACP Reductase and the Phe203Leu Mutant: A Proposed Mechanism for Drug Resistance |
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| المؤلفون: | Christie G. Brouillette, Steve Dunham, Karen Siegel, Mark E. Snow, Irina I. Protasevich, J. Ronald Rubin, Rocco Gogliotti |
| المصدر: | Biochemistry. 43:13380-13389 |
| بيانات النشر: | American Chemical Society (ACS), 2004. |
| سنة النشر: | 2004 |
| مصطلحات موضوعية: | Protein Folding, Hot Temperature, Protein Conformation, Stereochemistry, Entropy, Phenylalanine, Mutant, Calorimetry, Reductase, medicine.disease_cause, Biochemistry, Structure-Activity Relationship, Phenols, Leucine, Drug Resistance, Bacterial, medicine, Point Mutation, Enzyme Inhibitors, Ternary complex, Escherichia coli, chemistry.chemical_classification, Binding Sites, Chemistry, Escherichia coli Proteins, Cooperative binding, Isothermal titration calorimetry, Enoyl-(Acyl-Carrier-Protein) Reductase (NADH), Recombinant Proteins, Enzyme, Thermodynamics, Fatty Acid Synthases, Oxidoreductases |
| الوصف: | The antibacterial target enoyl-acyl carrier protein (ACP) reductase is a homotetrameric enzyme that catalyzes the last reductive step of fatty acid biosynthesis. In the present paper, four 2-(2-hydroxyphenoxy)phenol inhibitors, wherein the 4-position substituent varied from H to n-propyl, were studied to determine the contribution of the aliphatic chain to the binding to the wild-type (wt) enoyl-ACP reductase from Escherichia coli (FabI) and a drug-resistant mutant, (F203L)FabI, in which phenylalanine 203 is mutated to leucine. Thermodynamic parameters of ternary complex formation (enzyme-NAD(+)-inhibitor) were determined by isothermal titration calorimetry. The inhibitor affinity to wt FabI and (F203L)FabI increases with increasing aliphatic chain length, although the corresponding affinity for (F203L)FabI is lower, and also, it shows no detectable binding to the 4-H inhibitor. A distinguishing feature of inhibitor binding to either binary enzyme-NAD(+) complex is the apparent negative cooperativity for binding to the tetramer with half-site occupancy. For both enzymes, binding is enthalpy, DeltaH, driven. However, binding DeltaH becomes less favorable with increasing aliphatic chain length. Increases in affinity are found to be exclusively due to favorable changes in solvation entropy. Incremental changes in thermodynamic parameters within the series of inhibitors binding to wt FabI and (F203L)FabI are approximately the same. However, absolute differences between the two enzymes for binding to a given inhibitor are significant, suggesting different binding modes. This finding, coupled with a binding site conformation that is likely to be more rigid in the mutant, appears to result in the drug resistance of (F203L)FabI. |
| تدمد: | 1520-4995 0006-2960 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e29e30a8da8d90925180fce965cd6cca https://doi.org/10.1021/bi0492509 |
| رقم الأكسشن: | edsair.doi.dedup.....e29e30a8da8d90925180fce965cd6cca |
| قاعدة البيانات: | OpenAIRE |
Find this issue from the American Chemical Society | تدمد: | 15204995 00062960 |
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