Substrate selectivity of YgfU, a uric acid transporter from Escherichia coli.

ABSTRACT: The ubiquitous nucleobase-ascorbate transporter (NAT/NCS2) family includes more than 2,000 members, but only 15 have been characterized experimentally. Escherichia coli has 10 members, of which the uracil permease UraA and the xanthine permeases XanQ and XanP are functionally known. Of the remaining members, YgfU is closely related in sequence and genomic locus with XanQ. We analyzed YgfU and showed that it is a proton-gradient dependent, low-affinity (K(m) 0.5 mM), and high-capacity transporter for uric acid. It also shows a low capacity for transport of xanthine at 37 °C but not at 25 °C. Based on the set of positions delineated as important from our previous Cys-scanning analysis of permease XanQ, we subjected YgfU to rationally designed site-directed mutagenesis. The results show that

SUBMITTER: Papakostas K 

PROVIDER: S-EPMC3346081 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature