| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
It is important subject to understand the infection mechanism of bacteria or a virus. When thinking of the problem of new nature and a revival infection disease. Therefore, research of the protein toxins which are produced as pathogenic factor of bacterial infection symptom.
In the natural organism, when the bacterial toxins are infected in host cell, for the first steps, it is essential for binding the toxins to the cell associated receprors and co-receptors. These mechanisms are normally occurred in protein-protein interactions between infectious toxins and host cell receptors. In order to observe the interaction of these host cell and bacterial toxin on an atomic level, protein X-rays structural analysis is an effective technique. For this purpose, in this study, three types of bacterial toxins are crystallized and done the structural analyses.
(1) CRM (cross-reactive material) 197, a mutant Diphtheria Toxin with a Gly52 to Glu52 substitution in its A domain, is unable to ADP-ribosyla
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te EF-2 in vitro because of its extremely low affinity of NAD. Therefore, this mutant is used as a conjugate vaccine for the various virus and bacteria. To elucidate for the low affinity of NAD in CRM197 and to understand the detailed conformational changes of this mutant, we crystallized of CRM197 and determined the three dimensional structure at 2.6 A resolution.
(2) PMT is a major component of bacterial protein in Pasteurella multocida. This protein toxin consists of a 1285 amino acids. It revealed that the N-terminal domain contains receptor binding site and translocation domain, whereas catalytic domain is located in the C-terminal part of the protein. The catalytic function of PMT still unclear. It modulates the activity of the Gq/11 family of heterotrimetric G proteins, more specifically Gq. Several biochemical approaches are done for investigating the enzymatic activity of this protein toxin. But unfortunately it is not determined. For the purpose of investigate for the function of PM toxin, we crystallized of the C-terminal catalytic domain of the PM toxin and the structural determination has been done using SAD/MAD methods at 1.9 A resolution.
(3) CPE toxin is a major component of bacterial protein in Clostridium perfringens. This bacterial toxin is though as a pore-forming protein on the membrane of cell surface. For the purpose of understanding the mechanism of pore-formation of this bacterial toxin, the crystallization of CPE has been done for determining the three dimensional structure of CPE. Less
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