Interaction of cell division proteins with pbp2b and effects in morphogenesis of Streptococcus pneumoniae.

NUBIA YANDAR; GERMAN PINAS; NICOLAS REINOSO; PAULO CORTES; JOSE ECHENIQUE

Cordoba

Congreso; Reunión Anual de la Sociedad Argentina de Microbiologia General; 2015

The penicillin-binding proteins (PBPs) are enzymes involved in cell wall synthesis and cell division in Streptococcuspneumoniae. We have previously described that Cp1015 strain containing pbp2b mutations (from clinical strains that conferβ-lactam resistance) showed a pneumococcal subpopulation with bacillary shape, atypical septum formation and positioning,frequent asymmetrical divisions, and a PBP2b and FtsZ delocalization. These results suggested that PBP2b is involved inessential processes related to cell shape determination and cell division. By two-hybrid assays, we revealed that PBP2binteracted with proteins such as EzrA, MreC, RodA and FtsA, which were involved in cell division in S.pneumoniae. Weconstructed the mreC, mreD, rodA, ftsA and ezrA mutants by insertion-duplication mutagenesis. This mutants displayed smallcolonies, fitness, morphological and cell-wall biosynthesis alterations by vancomycin-fluorescein staining. In this study weobtained double mutants by sequential transformation of this proteins with PBP2b and PBP2b28 -GFP. They revealed elongatedphenotype, a variety of morphology defects: ?twisted-towel? shape, bind together chains, terminal thickens and aggregates ofPBP2b and PBP2b28 -GFP. These results suggested that ErzA, MreC, MreD, RodA and FtsA could contribute, together withPBP2b, to determine the pneumococcal cell shape of S. pneumoniae.