Involvement of the putative metal efflux protein YbeX in ribosomal metabolism

Abstract

YbeX of Escherichia coli, a member of CorC protein family, is a putative Co2+/ Mg2+ efflux factor. Here, we describe several{Delta} ybeX phenotypes and report an involvement of YbeX in ribosomal metabolism. E. coli lacking ybeX has a longer lag phase on outgrowth from the stationary phase. This phenotype is heterogeneous at the individual cell level and can be rescued by supplementing the growth media with magnesium.{Delta} ybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics, which have a common ability to induce the cold shock response in E. coli.{Delta} ybeX cells accumulate distinct 16S rRNA degradation intermediates present in both 30S particles and 70S ribosomes. We propose that a function of YbeX is maintaining the magnesium homeostasis in the cell, which is needed for proper ribosomal assembly.