Active site plasticity revealed from the structure of the enterobacterial N-ribohydrolase RihA bound to a competitive inhibitor.

ABSTRACT:

Background

Pyrimidine-preferring N-ribohydrolases (CU-NHs) are a class of Ca2+-dependent enzymes that catalyze the hydrolytic cleavage of the N-glycosidic bond in pyrimidine nucleosides. With the exception of few selected organisms, their physiological relevance in prokaryotes and eukaryotes is yet under investigation.

Results

Here, we report the first crystal structure of a CU-NH bound to a competitive inhibitor, the complex between the Escherichia coli enzyme RihA bound to 3, 4-diaminophenyl-iminoribitol (DAPIR) to a resolution of 2.1 A. The ligand can bind at the active site in two distinct orientations, and the stabilization of two flexible active site regions is pivotal to establish the interactions required for substrate discrimination and catalysis.

Conclusions

SUBMITTER: Garau G 

PROVIDER: S-EPMC2898832 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature