2013 Fiscal Year Final Research Report
Crystal structure of glucansucrase from the dental caries pathogen, Streptococcus mutans
| Project/Area Number |
23780139
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Food science
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| Research Institution | University of Shizuoka |
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Principal Investigator |
ITO Keisuke 静岡県立大学, 食品栄養科学部, 助教 (40580460)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 虫歯（う蝕） / Streptococcus mutans / 糖転移酵素 / 機能性食品 / ペプチド / X線結晶構造解析 |
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| Research Abstract |
Streptococcus mutans is the dental caries pathogen. Caries formation is initiated when glucan, a sticky glucose polymer produced by S. mutans, forms a biofilm (dental plaque) on teeth. The GTF-SI from S. mutans is the key enzyme for the biofilm formation. The structure of GTF-SI analyzed in this study showed that the domain order of GTF-SI was circularly permuted as compared to common GH family 13 amylases. Based on the apo GTF-SI structure and the structures in complex with its inhibitors, we proposed its transglycosyl reaction mechanism via glycosyl-enzyme intermediate in subsite -1. Most importantly, our study reveals that the conformations of the glucose moiety in subsite +1 determines the transglycosyl reaction specificity of glucansucrases. In addition to structural differences in subsite +1, GTF-SI possesses unique structural features in subsite +2. The information should be extremely useful to design new inhibitors to prevent the biofilm formation by the GTF-SI.
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