1988 Fiscal Year Final Research Report Summary
Bacterial enterotoxin receptor and its signal transduction
| Project/Area Number |
62570184
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TOSHIYA Hirayama The Institute of Medical Science, The University of Tokyo, 医科学研究所, 助教授 (50050696)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Bacterial enterotoxin / Heat-sable enterotoxin / Enterotoxin / Receptor / フォトアフィニティラベル |
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| Research Abstract |
In this project, the identification of intestinal receptor for the heat-stable enterotoxin (STH) produced by enterotoxigenic Escherichia coli and the requirement for toxin's unique structure to bind the receptor were investigated. The toxin contains 19 amino acid residues and causes secretory diarrhea in human and animals by activating guanylate cyclase in the intestine. The region 6-18 has a cyclindrical structure formed by three disulfide bonds and represents the active domain of the enterotoxin.
I examined the binding site of STh in rat intestinal cell membrane by using radioiodinated synthetic STh[5-19] (^<125>I-ANB-STh[5-19]) which id covalently coupled through the N-terminus to the photoactive reagent, N-5-azido-2-nitrobenzoyl-succinimide (ANB-NOS). After incubation of purified intestinal cell membrane with ^<125>I-ZNB-STh[5-19] for 15 min at 30゜C, the samples were subsequently photolyzed at 254 nm. The protein with molecular size of 70,000, designated as 70-KDa protein,was specifically labeled with the photoreactive STh analogue and this labeling was completely inhibited by the active analogues of STh and also by active analogues of heat-stable enterotoxin of Yersinia enterocolitica (Y-ST) and Vibrio cholerae non-Ol (NAG-ST), suggesting that these heat-satble enterotoxins share common receptor protein.
By using the synthetic STh analogues with various combination of disulfide bonds, which are important for construction and stabilization of the spatial structure of STh to express its toxicity, the spatial structure of STh is also necessary for its binding to the 70-KDa protein.
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Research Products
(11 results)
