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The three‐dimensional structure of trichosanthin refined at 2.7 Å resolution
Author(s) -
Xia ZongXiang,
Zhang Lei,
Zhang ZhiMing,
Wu Shen,
Dong YiCheng
Publication year - 1993
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19930110314
Subject(s) - trichosanthin , chemistry , crystallography , resolution (logic) , hydrogen bond , molecule , stereochemistry , root mean square , amino acid , amino acid residue , peptide sequence , biochemistry , organic chemistry , electrical engineering , engineering , artificial intelligence , computer science , gene
The three‐dimensional structure of trichosanthin crystallizing in space group C2 has been refined at 2.7 Å resolution from a previously reported starting model at 3 Å resolution based on a solvent flattened map and the revised primary structure consisting of 247 amino‐acids. The final R ‐factor is 19.2% with the root mean‐square deviations of 0.018 Å from ideal bond lengths and of 2.2 ˙ from ideal bond angles. Trichosanthin molecule is composed of two domains, the large domain consisting of 181 amino‐acid residues starting from N ‐terminus and the small domain consisting of the rest of the amino‐acid residues. The molecule contains eight α‐helices. five β‐sheets made of sixteen β‐strands, and some reverse turns. It is noteworthy that some of the α‐helices and β‐sheets show irregular hydrogen bonding patterns. Six of the thirteen residues absolutely conserved in eleven ribosome‐inactivating proteins are located in a cleft near the interface of the two domains and they are likely to be active sites. Three additional conservative residues located in the cleft region might make some functional contribution as well.