Role of Phe283 in enzymatic reaction of cyclodextrin glycosyltransferase from alkalophilic Bacillus sp.1011: Substrate binding and arrangement of the catalytic site.

ABSTRACT: Cyclodextrin glycosyltransferase (CGTase) belonging to the alpha-amylase family mainly catalyzes transglycosylation and produces cyclodextrins from starch and related alpha-1,4-glucans. The catalytic site of CGTase specifically conserves four aromatic residues, Phe183, Tyr195, Phe259, and Phe283, which are not found in alpha-amylase. To elucidate the structural role of Phe283, we determined the crystal structures of native and acarbose-complexed mutant CGTases in which Phe283 was replaced with leucine (F283L) or tyrosine (F283Y). The temperature factors of the region 259-269 in native F283L increased >10 A(2) compared with the wild type. The complex formation with acarbose not only increased the temperature factors (>10 A(2)) but also changed the structure of the region 257-267. This regio

SUBMITTER: Kanai R 

PROVIDER: S-EPMC2286706 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature