Porphyrin-mediated binding to hemoglobin by the HA2 domain of cysteine proteinases (gingipains) and hemagglutinins from the periodontal pathogen Porphyromonas gingivalis.

ABSTRACT: Heme binding and uptake are considered fundamental to the growth and virulence of the gram-negative periodontal pathogen Porphyromonas gingivalis. We therefore examined the potential role of the dominant P. gingivalis cysteine proteinases (gingipains) in the acquisition of heme from the environment. A recombinant hemoglobin-binding domain that is conserved between two predominant gingipains (domain HA2) demonstrated tight binding to hemin (Kd = 16 nM), and binding was inhibited by iron-free protoporphyrin IX (Ki = 2.5 microM). Hemoglobin binding to the gingipains and the recombinant HA2 (rHA2) domain (Kd = 2.1 nM) was also inhibited by protoporphyrin IX (Ki = 10 microM), demonstrating an essential interaction between the HA2 domain and the heme moiety in hemoglobin binding. Binding of rHA2

SUBMITTER: DeCarlo AA 

PROVIDER: S-EPMC93857 | biostudies-literature | 1999 Jun

REPOSITORIES: biostudies-literature