Neutralization of toxic haem by Porphyromonas gingivalis haemoglobin receptor.
Free haem is known to be toxic to organs, tissues and cells. It enhances permeability by binding to a cell membrane, which leads to cell death, and damages lipids, proteins and DNA through the generation of reactive oxygen species. Lysine- and arginine-specific gingipains (Kgp and RgpA/B) are major proteinases that play an important role in the pathogenicity of a black-pigmented periodontopathogen named Porphyromonas gingivalis. One of the adhesin domains of gingipain, HbR could bind haem as an iron nutrient source for P. gingivalis. Using erythrocyte and its membrane as a model, results from the present study demonstrate that recombinant HbR expressed in Escherichia coli could inhibit haem-induced haemolysis, probably through removing haem from the haem-membrane complex and lowering free haem toxicity by mediating dimerization of haem molecules. The ability to protect a cell membrane from haem toxicity is a new function for HbR.
Nhien
Nguyen Thanh Thuy
NT
Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan.
Huy
Nguyen Tien
NT
Naito
Mariko
M
Oida
Tatsuo
T
Uyen
Dinh Thanh
DT
Huang
Mingguo
M
Kikuchi
Mihoko
M
Harada
Shigeharu
S
Nakayama
Koji
K
Hirayama
Kenji
K
Kamei
Kaeko
K
D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D004926:Escherichia coli / Q000378:metabolism; D000080867:Gingipain Cysteine Endopeptidases; D006242:Haptoglobins / Q000378:metabolism; D006418:Heme / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D015227:Lipid Peroxidation; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012710:Serum Albumin, Bovine / Q000378:metabolism
D018829:Adhesins, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D006242:Haptoglobins; D011994:Recombinant Proteins; D012710:Serum Albumin, Bovine; D006418:Heme; D003546:Cysteine Endopeptidases