Genetic and biochemical characterization of glycerol uptake in Mycoplasma mycoides subsp mycoides SC: Its impact on H2O2 production and virulence

Highly virulent strains of Mycoplasma mycoides subsp, mycoides SC belonging to the African cluster contain an operon with the genes gtsA, gtsB, and gt sC, encoding membrane ATP binding cassette transporter proteins GtsA, GtsB, and GtsC, which are involved in glycerol transport. Strain Afade from the African cluster incorporated [U-C-14]glycerol with a time-dependent increas e. The less virulent strain L2 of the European cluster, which lacks gtsB an d gtsC, failed to incorporate glycerol, Antibodies against GtsB noncompetit ively inhibited glycerol uptake. L-alpha -Glycerophosphate was not transpor ted by M. mycoides subsp, mycoides SC. It is postulated to be synthesized b y phosphorylation of glycerol during transport and subsequently metabolized further to dihydroxyacetone phosphate accompanied by release of H2O2. Pero xide production in glycerol-containing growth medium was high for the Afric an strain Afade but very low for the European strain L2, Virtually no H2O2 was produced by both strains without glycerol, Hence, the efficient glycero l uptake system found in the virulent strain of the African cluster leads t o a strong release of peroxide, a potential virulence factor which is lacki ng in the less virulent European strains. M, mycoides subsp, mycoides SC mi ght have adopted, as a strategy for virulence, a highly efficient uptake sy stem for glycerol which allows the production of an active metabolic interm ediate that damages host cells.