Autolytic Activity and Plasma Binding Study of Aap, a Novel Minor Autolysin of Streptococcus pneumoniae.
Pneumococcal autolysins are enzymes involved in cell wall turnover and cellular division physiologically. They have been found to be involved in the pneumococcus pathogenesis. The aim of this study was to identify the autolytic activity of Spr1754 as a novel protein of Streptococcus pneumoniae. Moreover, the binding of the recombinant protein to plasma proteins was also determined. The spr1754 gene was amplified by PCR and cloned into the pET21a(+) prokaryotic expression vector. The constructed pET21a(+)/spr1754 recombinant plasmid was transformed into E. coli Origami (DE3) and induced using IPTG. The recombinant protein of Spr1754 was purified by Ni-NTA affinity chromatography and confirmed by SDS-PAGE and Western blot analysis using anti-His tag monoclonal antibody. Autolytic activity and the ability of the recombinant protein in binding to plasma proteins were performed using zymogram analysis and western blot, respectively. The spr1754 with expected size was cloned and overexpressed in Escherichia coli Origami (DE3), successfully. After purification of the Spr1754 recombinant protein, the autolytic activity was observed by zymography. Of the four plasma proteins used in this study, binding of lactoferrin to Spr1754 recombinant protein was shown. The Spr1754 recombinant protein has a bifunctional activity, i.e., as being autolysin and lactoferrin binding and designated as Aap (autolytic/ adhesion/ pneumococcus). Nevertheless, characterization of the Aap needs to be followed using gene inactivation and cell wall localization.
Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Ramina
R
Mahboobi
Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Davoud
D
Afshar
Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Mohammad Reza
MR
Pourmand
Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Rahil
R
Mashhadi
D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D005822:Genetic Vectors; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins; D013296:Streptococcus pneumoniae / Q000235:genetics*
D011994:Recombinant Proteins; D009238:N-Acetylmuramoyl-L-alanine Amidase
Minor autolysin; Spr 1754; Streptococcus pneumonia