Congresos y reuniones científicas
Título:
PBP2B controls the shape determination and cell division mechanisms of Streptococcus pneumoniae
Autor/es:
ALBARRACIN ORIO AG, PIÑAS GE, CORTES PR, CIAN MB, ECHENIQUE J
Lugar:
POTRERO DE LOS FUNES
Reunión:
Encuentro; Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011
Institución organizadora:
SAIB
Resumen:
Mutations in penicillin-binding proteins (PBPs) PBP1a, PBP2x, and
PBP2b confer ß-Lactam resistance in S. pneumoniae. These
enzymes are involved in cell wall synthesis and cell division. We
described that laboratory strain harboring pbp2b mutations showed
morphological abnormalities (rod-shaped cells) with an abnormal
septum pattern, suggesting alterations in the cell division
mechanism. These cell alterations were compensated by the
acquisition of pbp2x and pbp1a resistance-conferring mutations
obtained from clinical strains.
Analyzing PBP-tag protein fusions, we demonstrated that all these
pbp mutations conferred an increased stability to their respective
mutant proteins, suggesting that a higher half-life of PBP2x and
PBP1a mutant proteins is necessary to compensate the increased
half-life of the PBP2b mutant protein (PBP2b*). Probably this
compensation is related to a coordinated enzymatic activity between
PBPs.
In the pbp2b mutants, we demonstrated that the FtsZ and PBP2B*
were delocalized, and that PBP2b* displayed a helix manner, similar
to that showed by FtsZ in the same pbp2b mutants. By two-hybrid
system assays, we detected a protein-protein interaction between
FtsZ and PBP2b*, suggesting that the cell division alterations are
caused by this interaction. We propose that PBP2b participates in the
control of shape determination and cell division mechanisms in
S.pneumoniae.