MapA: a protein involved in the envelope biogénesis of Brucella suis

RUIZ-RANWEZ, M.V.; POSADAS, D. M.; RUSSO, D. M.; BIALER, M. G. ; ABDIAN, P; ZORREGUIETA, A

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2014

Sociedad Argentina de Bioquímica y Biología Molecular

Brucellae have a cell surface with distinctive properties, which make them more resistant to polycationic peptides and more permeable to hydrophobic compounds. It has been proposed that this would reflect an adaptation to intracellular parasitism. We have identified a gene of B. suis encoding a protein (MapA) predicted to localize in the cell envelope. The ∆mapA mutant did not show differences compared to the parental strain regarding: i) outer membrane protein profiles, ii) growth curves in rich medium or under saline stress and iii) tolerance to acidic pH and complement present in porcine serum. Instead, the mutant showed an enhanced sensitivity to Triton X-100, Polymyxin B (a cationic lipopeptide) and Lysozyme. Observation of the phenotype of ∆mapA with acriflavine and LPS analysis by SDS-PAGE and silver staining suggest that the O-antigen portion of the LPS is not altered in the mutant. Interestingly, the mutant colonies in the presence of crystal violet showed a differential staining compared with the wild type. In addition, the ∆mapA mutant was impaired in the binding to HeLa cells probably due to an altered cell surface. These results suggest that MapA play a role in the integrity of the Brucella cell envelope.