Adaptation of Lacticaseibacillus rhamnosus CM MSU 529 to aerobic and respiratory growth: a proteomic approach

Lacticaseibacillus rhamnosus CM MSU 529 is the O2-tolerant facultative homofermentative lactic acid bacteria realizing respiratory metabolism when grown in a supplemented with hemin and vitamin K2 nutrient medium. This study describes the effect of aerobic and respiratory conditions on biomass and proteome of strain CM MSU 529 grown in a batch culture. Aeration caused the induction of the biosynthesis of 43 proteins, while 14 proteins were down-regulated as detected by label-free LC-MS/MS. Up-regulated proteins are involved in oxygen consumption (Pox, LctO, pyridoxine 5'-phosphate oxidase), xylulose-5-phosphate conversion (Xfp), pyruvate metabolism (PdhD, AlsS, AlsD), reactive oxygen species (ROS) elimination (Tpx, TrxA, Npx), general stress response (GroES, PfpI, universal stress protein, YqiG), antioxidant production (CysK, DkgA), pyrimidine metabolism (CarA, CarB, PyrE, PyrC, PyrB, PyrR), oligopeptide transport and metabolism (OppA, PepO), maturation and stability of ribosomal subunits (RbfA, VicX). Down-regulated proteins participate in ROS defense (AhpC), citrate and pyruvate consumption (CitE, PflB), oxaloacetate production (AvtA), arginine synthesis (ArgG), amino acid transport (GlnQ), and deoxy-nucleoside biosynthesis (RtpR). Overproduction of purine biosynthesis enzyme (PurE) distinguished cells grown under respiratory conditions from cells grown under aerobiosis. The data obtained shed light on mechanisms providing O2-tolerance and adaptation to aerobic/respiratory conditions in strain CM MSU 529.