| Project/Area Number |
60580128
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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 |
物質生物化学
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| Research Institution | University of Tokyo |
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Principal Investigator |
MITSUI Yukio University of Tokyo, 薬学部, 助手 (40012637)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Kazuo University of Tokyo, 薬学部, 助手 (00012675)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | X-ray Analysis / Crystal Structure Analysis / Enzyme / Substrate / Enzyme Reaction / Three-dimensional Structure of Enzymes / 誘導適合 |
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| Research Abstract |
Regarding a microbial proteinase "Subtilisin" and its substrate (actually proteinaceous inhibitor) "SSI"(Streptomyces Subtilisin Inhibitor), the followings have been achieved or elucidated.
1) Resolution of the crystal structure analysis of free SSI was raised to 1.85 <ang> (from 2.6 <ang> ).
2) Resolution of the crystal structure analysis of SSI-Subtilisin complex was raised to 2.0 <ang> (from 2.6 <ang> ).
3) Making use of the results of 1) and 2), the detailed nature of the conformational change imposed on the enzyme Subtilisin and the substrate SSI upon complex formation was analyzed. For this analysis, the newly devised "Difference Distance Map" and the "Relative Difference Distance Map" were fully made use of. 3A) The global structure of the enzyme Subtilisin is virtually unchanged after complex formation with the substrate SSI, although some local induced-fit movement does occur. 3B) The substrate SSI undergoes global conformational change upon complex formation with the enzyme Subtilisin in the way described below. a) No conspicuous conformational changes occur within any local structure formed by 10 consecutive amino acid residues, b) no <alpha> -helices per se undergoes any significant conformational change, c) no conspicuous changes occur in the relative disposition of any two neighbouring <beta> -strands, d) the <alpha_1> -helix is separated from the <beta_1> - and <beta_2> -strands by ca. 2 <ang> . 3C) The mechanism of conformational change described in 3B) above is unique in the light of the two well-known mechanisms, the "hinge bending mechanism" and the "helix shear mechanism".
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