Involvement of the putative metal efflux protein YbeX in ribosomal metabolism

Abstract

YbeX ofEscherichia coli, a member of CorC protein family, is a putative Co2+/ Mg2+efflux factor. Here, we describe severalΔybeXphenotypes and report an involvement of YbeX in ribosomal metabolism.E. colilackingybeXhas 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.ΔybeXstrain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics, which have a common ability to induce the cold shock response inE. coli.ΔybeXcells 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.