Crystal structure and mechanism of the Escherichia coli ArnA (PmrI) transformylase domain. An enzyme for lipid A modification with 4-amino-4-deoxy-L-arabinose and polymyxin resistance.

ABSTRACT: Gram-negative bacteria have evolved mechanisms to resist the bactericidal action of cationic antimicrobial peptides of the innate immune system and antibiotics such as polymyxin. The strategy involves the addition of the positively charged sugar 4-amino-4-deoxy-l-arabinose (Ara4N) to lipid A in their outer membrane. ArnA is a key enzyme in the Ara4N-lipid A modification pathway. It is a bifunctional enzyme catalyzing (1) the oxidative decarboxylation of UDP-glucuronic acid (UDP-GlcA) to the UDP-4' '-ketopentose [UDP-beta-(l-threo-pentapyranosyl-4' '-ulose] and (2) the N-10-formyltetrahydrofolate-dependent formylation of UDP-Ara4N. Here we demonstrate that the transformylase activity of the Escherichia coli ArnA is contained in its 300 N-terminal residues. We designate it the ArnA transform

SUBMITTER: Gatzeva-Topalova PZ 

PROVIDER: S-EPMC2583347 | biostudies-literature | 2005 Apr

REPOSITORIES: biostudies-literature