Mycobacterium tuberculosis dihydrofolate reductase reveals two conformational states and a possible low affinity mechanism to antifolate drugs.

Abstract

Inhibition of the biosynthesis of tetrahydrofolate (THF) has long been a focus in the treatment of both cancer and infectious diseases. Dihydrofolate reductase (DHFR), which catalyzes the last step, is one of the most thoroughly explored targets of this pathway, but there are no DHFR inhibitors used for tuberculosis treatment. Here, we report a structural, site-directed mutagenesis and calorimetric analysis of Mycobacterium tuberculosis DHFR (MtDHFR) in complex with classical DHFR inhibitors. Our study provides insights into the weak inhibition of MtDHFR by trimethoprim and other antifolate drugs, such as pyrimethamine and cycloguanil. The construction of the mutant Y100F, together with calorimetric studies, gives insights into low affinity of MtDHFR for classical DHFR inhibitors. Finally, the structures of MtDHFR in complex with pyrimethamine and cycloguanil define important interactions in the active site and provide clues to the more effective design of antibiotics targeted against MtDHFR.

• Authors: Marcio Vinicius Bertacine Dias, Petros Tyrakis, Romenia Ramos Domingues, Adriana Franco Paes Leme, Tom L Blundell
• Journal: Structure (London, England : 1993) (Structure) Vol. 22 Issue 1 Pg. 94-103 (Jan 07 2014) ISSN: 1878-4186 [Electronic] United States
• PMID: 24210757 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical References

• Bacterial Proteins
• Enzyme Inhibitors
• Folic Acid Antagonists
• Ligands
• Recombinant Proteins
• Triazines
• cycloguanil
• Trimethoprim
• Tetrahydrofolate Dehydrogenase
• Proguanil
• Pyrimethamine

Topics

• Bacterial Proteins (antagonists & inhibitors, chemistry, genetics, metabolism)
• Calorimetry
• Crystallography, X-Ray
• Enzyme Inhibitors (chemistry)
• Escherichia coli (genetics, metabolism)
• Folic Acid Antagonists (chemistry)
• Ligands
• Molecular Docking Simulation
• Mutagenesis, Site-Directed
• Mycobacterium tuberculosis (chemistry, enzymology, genetics)
• Proguanil (chemistry)
• Protein Conformation
• Pyrimethamine (chemistry)
• Recombinant Proteins (chemistry, genetics, metabolism)
• Structure-Activity Relationship
• Tetrahydrofolate Dehydrogenase (chemistry, genetics, metabolism)
• Thermodynamics
• Triazines (chemistry)
• Trimethoprim (chemistry)