title: Cloning of poly(aspartic acid) (PAA) hydrolase-1 gene from Pedobacter sp. KP-2 and hydrolysis of thermally synthesized PAA by its gene product.
abstract: Pedobacter sp. KP-2 can degrade and metabolize thermally synthesized alpha,beta-poly(D,L-aspartic acid) (tPAA), which contains 70% of unnatural beta-amide units, with high-molecular-weight. In this study, gene cloning and molecular characterization of PAA hydrolase-1 from KP-2 was carried out. Gene analysis reveals that deduced amino acid sequence of the enzyme shows a similarity to only that of PAA hydrolase-1 from Sphingomonas sp. KT-1. GPC and NMR analyses of the hydrolyzed products of tPAA by PAA hydrolase-1 of KP-2 indicate that this enzyme cleaves the beta-beta amide linkage via endo-mode to yield oligo(aspartic acid) from tPAA. Taking the composition of tPAA and the substrate specificity of PAA hydrolase-1 into consideration, the enzyme possibly plays a crucial role in tPAA biodegradation by KP-2.
authors.affiliation: Bioengineering Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan. thiraish@riken.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hiraishi
authors.forename: Eriko
authors.initials: E
authors.lastname: Masuda
authors.forename: Naoki
authors.initials: N
authors.lastname: Kanayama
authors.forename: Madoka
authors.initials: M
authors.lastname: Nagata
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Doi
authors.forename: Hideki
authors.initials: H
authors.lastname: Abe
authors.forename: Mizuo
authors.initials: M
authors.lastname: Maeda