The hpx genetic system for hypoxanthine assimilation as a nitrogen source in Klebsiella pneumoniae: gene organization and transcriptional regulation.

ABSTRACT: Growth experiments showed that adenine and hypoxanthine can be used as nitrogen sources by several strains of K. pneumoniae under aerobic conditions. The assimilation of all nitrogens from these purines indicates that the catabolic pathway is complete and proceeds past allantoin. Here we identify the genetic system responsible for the oxidation of hypoxanthine to allantoin in K. pneumoniae. The hpx cluster consists of seven genes, for which an organization in four transcriptional units, hpxDE, hpxR, hpxO, and hpxPQT, is proposed. The proteins involved in the oxidation of hypoxanthine (HpxDE) or uric acid (HpxO) did not display any similarity to other reported enzymes known to catalyze these reactions but instead are similar to oxygenases acting on aromatic compounds. Expression of the hpx

SUBMITTER: de la Riva L 

PROVIDER: S-EPMC2593211 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature