RRC ID 35486
Author Xiao Y, Gerth K, Müller R, Wall D.
Title Myxobacterium-produced antibiotic TA (myxovirescin) inhibits type II signal peptidase.
Journal Antimicrob Agents Chemother
Abstract Antibiotic TA is a macrocyclic secondary metabolite produced by myxobacteria that has broad-spectrum bactericidal activity. The structure of TA is unique, and its molecular target is unknown. Here, we sought to elucidate TA's mode of action (MOA) through two parallel genetic approaches. First, chromosomal Escherichia coli TA-resistant mutants were isolated. One mutant that showed specific resistance toward TA was mapped and resulted from an IS4 insertion in the lpp gene, which encodes an abundant outer membrane (Braun's) lipoprotein. In a second approach, the comprehensive E. coli ASKA plasmid library was screened for overexpressing clones that conferred TA(r). This effort resulted in the isolation of the lspA gene, which encodes the type II signal peptidase that cleaves signal sequences from prolipoproteins. In whole cells, TA was shown to inhibit Lpp prolipoprotein processing, similar to the known LspA inhibitor globomycin. Based on genetic evidence and prior globomycin studies, a block in Lpp expression or prevention of Lpp covalent cell wall attachment confers TA(r) by alleviating a toxic buildup of mislocalized pro-Lpp. Taken together, these data argue that LspA is the molecular target of TA. Strikingly, the giant ta biosynthetic gene cluster encodes two lspA paralogs that we hypothesize play a role in producer strain resistance.
Volume 56(4)
Pages 2014-21
Published 2012-4-1
DOI 10.1128/AAC.06148-11
PII AAC.06148-11
PMID 22232277
PMC PMC3318312
MeSH Anti-Bacterial Agents / biosynthesis Anti-Bacterial Agents / pharmacology* Aspartic Acid Endopeptidases / antagonists & inhibitors* Aspartic Acid Endopeptidases / genetics Bacterial Proteins / antagonists & inhibitors* Bacterial Proteins / genetics Chromosome Mapping Chromosomes, Bacterial / drug effects Chromosomes, Bacterial / genetics Dose-Response Relationship, Drug Drug Resistance, Bacterial / genetics Escherichia coli / drug effects Macrolides / pharmacology* Microbial Sensitivity Tests Microscopy, Fluorescence Mutagenesis Myxococcus xanthus / metabolism* Peptides / pharmacology Plasmids / genetics Protease Inhibitors / pharmacology* Protein Biosynthesis / drug effects
IF 4.715
Times Cited 38
Prokaryotes E. coli JW0025(ASKA lspA) ASKA library