Methylthioinosine phosphorylase from Pseudomonas aeruginosa. Structure and annotation of a novel enzyme in quorum sensing.

ABSTRACT: The PA3004 gene of Pseudomonas aeruginosa PAO1 was originally annotated as a 5'-methylthioadenosine phosphorylase (MTAP). However, the PA3004 encoded protein uses 5'-methylthioinosine (MTI) as a preferred substrate and represents the only known example of a specific MTI phosphorylase (MTIP). MTIP does not utilize 5'-methylthioadenosine (MTA). Inosine is a weak substrate with a k(cat)/K(m) value 290-fold less than MTI and is the second best substrate identified. The crystal structure of P. aeruginosa MTIP (PaMTIP) in complex with hypoxanthine was determined to 2.8 Å resolution and revealed a 3-fold symmetric homotrimer. The methylthioribose and phosphate binding regions of PaMTIP are similar to MTAPs, and the purine binding region is similar to that of purine nucleoside phosphorylases (PNPs

SUBMITTER: Guan R 

PROVIDER: S-EPMC3040260 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature