EzrA, MreC, MreD, RodA and FtsA Interacts with PBP2b during cell division of Streptococcus pneumoniae

YANDAR, N.; ALBARRACIN ORIO AG; PIÑAS GE; CIAN MB; CORTES PR; ECHENIQUE J

Rosario

Congreso; Sociedad Argentina de Investigación Bioquímica y Biología Molecular,; 2014

SAIB

The penicillin-binding proteins (PBPs) are enzymes involved in peptidoglycan synthesis and cell division in bacteria. In S. pneumoniae, we have described that the pbp2b28 mutations confer β-lactam resistance and caused bacillary shape, atypical septum formation, asymmetrical divisions, and a PBP2B and FtsZ delocalization, suggesting that PBP2b is involved in the cell shape determination and cell division mechanisms. By bacterial two-hybrid assays, we revealed that PBP2b and PBP2b28 interacted with proteins such as EzrA, MreC, MreD, RodA and FtsA, which belong to divisome. We constructed insertion mutants in the genes that encode these proteins, and these ones displayed morphological and cell-wall biosynthesis alterations detected by vancomycin-fluorescein staining, which label peptidoglycan biosynthesis de novo. We also obtained the mreC, mreD, rodA, ftsA and ezrA mutants transformed with vectors that expressed PBP2b-GFP and PBP2b28-GFP. The expression of PBP2b28-GFP produced terminal thickens, shape changes and PBP2b28-GFP aggregates in all mutants. However, morphological defects such as ?twisted-towel? were observed only in the mreC, mreD and rodA mutants. These results suggested that MreC, MreD, RodA, FtsA and EzrA interact in different manner with PBP2b, probably coupled to other divisome proteins, to determine cell shape and cell division mechanism of S. pneumoniae.