The tandem repeats enabling reversible switching between the two phases of β-lactamase substrate spectrum.

ABSTRACT: Expansion or shrinkage of existing tandem repeats (TRs) associated with various biological processes has been actively studied in both prokaryotic and eukaryotic genomes, while their origin and biological implications remain mostly unknown. Here we describe various duplications (de novo TRs) that occurred in the coding region of a β-lactamase gene, where a conserved structure called the omega loop is encoded. These duplications that occurred under selection using ceftazidime conferred substrate spectrum extension to include the antibiotic. Under selective pressure with one of the original substrates (amoxicillin), a high level of reversion occurred in the mutant β-lactamase genes completing a cycle back to the original substrate spectrum. The de novo TRs coupled with reversion makes a gene

SUBMITTER: Yi H 

PROVIDER: S-EPMC4169377 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature