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Complete subsite mapping of a “loopful” GH19 chitinase from rye seeds based on its crystal structure
Author(s) -
Ohnuma Takayuki,
Umemoto Naoyuki,
Kondo Kaori,
Numata Tomoyuki,
Fukamizo Tamo
Publication year - 2013
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2013.07.008
Subject(s) - chitinase , chemistry , stereochemistry , tetrasaccharide , molecule , chitin , mutant , enzyme , biochemistry , organic chemistry , polysaccharide , chitosan , gene
Crystallographic analysis of a mutated form of “loopful” GH19 chitinase from rye seeds a double mutant RSC‐c, in which Glu67 and Trp72 are mutated to glutamine and alanine, respectively, (RSC‐c‐E67Q/W72A) in complex with chitin tetrasaccharide (GlcNAc) 4 revealed that the entire substrate‐binding cleft was completely occupied with the sugar residues of two (GlcNAc) 4 molecules. One (GlcNAc) 4 molecule bound to subsites −4 to −1, while the other bound to subsites +1 to +4. Comparisons of the main chain conformation between liganded RSC‐c‐E67Q/W72A and unliganded wild type RSC‐c suggested domain motion essential for catalysis. This is the first report on the complete subsite mapping of GH19 chitinase.