The role of proteases of periodontopathogens in iron acquisition
Project/Area Number |
11671827
|
Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Morphological basic dentistry
|
Research Institution | Matsumoto Dental University, School of Dentistry |
Principal Investigator |
FUJIMURA Setsuo Matsumoto Dental University, assoc.pro, 歯学部, 助教授 (40045505)
|
Project Period (FY) |
1999 – 2000
|
Project Status |
Completed (Fiscal Year 2000)
|
Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
Keywords | P.gingivalis / periodontopathogen / iron acquisition / proteases / iron acquisition / 歯周病 / 鉄獲得機構 / プロテアーゼ / Porphyromonas / ヘム蛋白質 |
Research Abstract |
In humans, extracellular irons are rapidly bound by transferring in serum and lactoferrin at mucosal surfaces. Thus the in vivo concentration of free iron is too low (10^<-18> M) to support the growth of microorganisms. Human adult periodontal pathogens including Porphyromonas gingivalis lack siderophore system, an iron chelate system. Therefore, these species must possess the specific mechanism for iron acquisition. We had considered that the microorganisms utilize hemoglobin of the erythrocytes in the diseased area as iron source, which was confirmed by our experiments. In this study, we observed that myoglobin another abundant hemoprotein in the body also serve as iron source. Myoglobin was found to bind reversibly to the envelope of P.gingivalis in a pH-dependent manner ; the binding took place below neutral pHs of the incubation mixtures and myoglobin bound released from the envelope at high pHs. The amounts of myoglobin bound to 1 mg of the envelope at pH 5.0 per min under the presence of sufficient myoglobin were 1.4μg. K_d for the reaction at pH 5.0 was 2.2×10^<-10> M.From the dot blot assay, myoglobin obviously bound to hemoglobin-binding protein (HbBP) of P.gingivalis, however, the amounts of myoglobin that bound to HbBP were half those of hemoglobin. One of the fractions, separated by gel filtration, of the digested materials of myoglobin by the detergent-solubilized envelope containing proteases was found to support the growth of P.gingivalis in the iron source-depleted medium.
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Report
(3 results)
Research Products
(4 results)