2AF6

Crystal structure of Mycobacterium tuberculosis Flavin dependent thymidylate synthase (Mtb ThyX) in the presence of co-factor FAD and substrate analog 5-Bromo-2'-Deoxyuridine-5'-Monophosphate (BrdUMP)

Summary for 2AF6

• Entry DOI: 10.2210/pdb2af6/pdb
• Descriptor: Thymidylate synthase thyX, IODIDE ION, FLAVIN-ADENINE DINUCLEOTIDE, ... (6 entities in total)
• Functional Keywords: m.tuberculosis, thyx, fdts, tscp, flavin dependent thymidylate synthase, transferase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 8
• Total formula weight: 243699.20

Authors

Sampathkumar, P.,Turley, S.,Ulmer, J.E.,Rhie, H.G.,Sibley, C.H.,Hol, W.G. (deposition date: 2005-07-25, release date: 2005-10-04, Last modification date: 2024-10-16)

Primary citation

Sampathkumar, P.,Turley, S.,Ulmer, J.E.,Rhie, H.G.,Sibley, C.H.,Hol, W.G.
Structure of the Mycobacterium tuberculosis Flavin Dependent Thymidylate Synthase (MtbThyX) at 2.0A Resolution.
J.Mol.Biol., 352:1091-1104, 2005

PubMed Abstract: A novel flavin-dependent thymidylate synthase was identified recently as an essential gene in many archaebacteria and some pathogenic eubacteria. This enzyme, ThyX, is a potential antibacterial drug target, since humans and most eukaryotes lack the thyX gene and depend upon the conventional thymidylate synthase (TS) for their dTMP requirements. We have cloned and overexpressed the thyX gene (Rv2754c) from Mycobacterium tuberculosis in Escherichia coli. The M.tuberculosis ThyX (MtbThyX) enzyme complements the E.coli chi2913 strain that lacks its conventional TS activity. The crystal structure of the homotetrameric MtbThyX was determined in the presence of the cofactor FAD and the substrate analog, 5-bromo-2'-deoxyuridine-5'-monophosphate (BrdUMP). In the active site, which is formed by three monomers, FAD is bound in an extended conformation with the adenosine ring in a deep pocket and BrdUMP in a closed conformation near the isoalloxazine ring. Structure-based mutational studies have revealed a critical role played by residues Lys165 and Arg168 in ThyX activity, possibly by governing access to the carbon atom to be methylated of a totally buried substrate dUMP.

PubMed: 16139296
DOI: 10.1016/j.jmb.2005.07.071

Experimental method

X-RAY DIFFRACTION (2.01 Å)