v5.1.0.3
Cicer data from the Legume Information System
Description | Pullulanases (pullulan 6-glucanohydrolase, EC 3.2.1.41) are debranching enzymes that are able to hydrolyze the alpha-1,6-glycosidic linkage in pullulan, starch, amylopectin, and related oligosaccharides. Type I pullulanases specifically cleave the alpha-1,6-glycosidic linkages in pullulan and branched oligosaccharides to produce maltotriose and linear oligosaccharides, respectively [1]. Structural analysis of Klebsiella lipoprotein pullulanase (PulA) illustrates that the catalytic core is composed of two major regions: the TIM-barrel domain A and beta-sandwich fold domain C. PulA contains an extra domain, a highly mobile Ins subdomain of unknown function which is inserted into the catalytic TIM-barrel domain A of Klebsiella pullulanases. The Ins subdomain is rich in helical and loop secondary structure. A disulfide bond between Cys491 and Cys506 and two Ca2+ ions presumably stabilizes this domain.This insertion is also found in pullulanases from other Gram-negative genera that have a functional T2SS, such as Vibrio, Aeromonas, and Photorhabdus. Functional analysis indicate that this domain is required for PulA secretion via the T2SS [2]. |
Namespace | Domain |