Purification, crystallization and preliminary structural characterization of the periplasmic domain P1 of the Escherichia coli membrane-protein insertase YidC.

In Escherichia coli, the biogenesis of inner membrane proteins (IMPs) requires targeting and insertion factors such as the signal recognition particle (SRP) and the Sec translocon. Recent studies have identified YidC as a novel and essential component involved in membrane insertion of IMPs both in conjunction with the Sec translocon and as a separate entity. E. coli YidC is a member of the YidC (in bacteria)/Oxa1 (in mitochondria)/Alb3 (in chloroplasts) protein family and contains six transmembrane segments and a very large periplasmic domain P1. The overproduction, purification, crystallization and preliminary crystallographic studies of the native and selenomethionine-labelled P1 domain are reported here as a first step towards the elucidation of the molecular mechanism of YidC as a membrane-protein insertase.