Haemoglobin receptor protein is intragenically encoded by the cysteine proteinase‐encoding genes and the haemagglutinin‐encoding gene of Porphyromonas gingivalis

Publisher Website
Google Scholar
Abstract
The obligately anaerobic bacterium Porphyromonas gingivalis produces characteristic black‐pigmented colonies on blood agar. It is thought that the black pigmentation is caused by haem accumulation and is related to virulence of the microorganism. P. gingivalis cells expressed a prominent 19 kDa protein when grown on blood agar plates. Analysis of its N‐terminal amino acid sequence indicated that the 19 kDa protein was encoded by an internal region (HGP15 domain) of an arginine‐specific cysteine proteinase (Arg‐gingipain, RGP)‐encoding gene (rgp1) and was also present in genes for lysine‐specific cysteine proteinases (prtP and kgp) and a haemagglutinin (hagA) of P. gingivalis. The HGP15 domain protein was purified from an HGP15‐overproducing Escherichia coli and was found to have the ability to bind to haemoglobin in a pH‐dependent manner. The anti‐HGP15 antiserum reacted with the 19 kDa haemoglobin‐binding protein in the envelope of P. gingivalis. P. gingivalis wild‐type strain showed pH‐dependent haemoglobin adsorption, whereas its non‐pigmented mutants that produced no HGP15‐related proteins showed deficiency in haemoglobin adsorption. These results strongly indicate a close relationship among HGP15 production, haemoglobin adsorption and haem accumulation of P. gingivalis.

This publication has 57 references indexed in Scilit: