4XT6: Crystal Structure Of Rv2671 From Mycobacterium Tuberculosis In Complex With The Tetrahydropteridine Ring Of Tetrahydrofolate (thf)

Mycobacterium tuberculosis (Mtb) Rv2671 is annotated as a 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate (AROPP) reductase (RibD) in the riboflavin biosynthetic pathway. Recently, a strain of Mtb with a mutation in the 5' untranslated region of Rv2671, which resulted in its overexpression, was found to be resistant to dihydrofolate reductase (DHFR) inhibitors including the anti-Mtb drug para-aminosalicylic acid (PAS). In this study, a biochemical analysis of Rv2671 showed that it was able to catalyze the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF), which explained why the overexpression of Rv2671 was sufficient to confer PAS resistance. We solved the structure of Rv2671 in complex with the NADP(+) and tetrahydrofolate (THF), which revealed the structural basis for the DHFR activity. The structures of Rv2671 complexed with two DHFR inhibitors, trimethoprim and trimetrexate, provided additional details of the substrate binding pocket and elucidated the differences between their inhibitory activities. Finally, Rv2671 was unable to catalyze the reduction of AROPP, which indicated that Rv2671 and its closely related orthologues are not involved in riboflavin biosynthesis.
PDB ID: 4XT6Download
MMDB ID: 136670
PDB Deposition Date: 2015/1/23
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 1.85  Å
Source Organism:
Similar Structures:
Biological Unit for 4XT6: dimeric; determined by author and by software (PISA)
Molecular Components in 4XT6
Label Count Molecule
Proteins (2 molecules)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB