************第３２回尾張コンプレックスセミナー*************

題　目：　Systematic Investigation on Mycolic Acid Cyclopropane 
Synthases Interaction with Cofactors and Sinefungin by ONIOM Study

発表者：　Darinee Sae-Tang
(Department of Chemistry, Faculty of Science, Kasetsart University)

日　時：　６月２５日（木）午後４時～

場　所：　情報科学研究科６階６１６号室

内　 容： 
The several systematically ONIOM2 methods were performed with 
B3LYP/6-31G(d,p):PM3 combination in cyclopropane synthase system 
with various model sized. The study presents SAM cofactor 
obviously strong interacts in cofactor binding site than SAH 
product with effect from methyl group at sulfur atom resulting 
in positive charge around sulfur and neighboring atom. In addition, 
water molecules observed in X-ray crystal structure play function 
with hydrogen bond bridging between cofactor and Asp70, thus water 
molecules were added in the system study. The results show requirement 
of these waters to be included in the high level of calculations 
and constrained them to present their interaction. Including Asp70 
or Glu124 residue with cofactor and water molecules in the inner 
layer shows not significantly different energy. In order to set 
up ONIOM model with many atoms in the system, in cyclopropane 
synthase system studied, adding cofactor with water molecules in 
the inner layer or high level of calculation can represent the 
interaction and appropriate energies.

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