Cloning of Poly(aspartic acid) (PAA) Hydrolase-1 Gene from Pedobacter sp KP-2 and Hydrolysis of Thermally Synthesized PAA by its Gene Product
Cloning of Poly(aspartic acid) (PAA) Hydrolase-1 Gene from Pedobacter sp KP-2 and Hydrolysis of Thermally Synthesized PAA by its Gene Product
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DOI：
10.1002/mabi.200800106
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发表时间：
2009-01-09
影响因子：
4.6
通讯作者：
Maeda, Mizuo
中科院分区：
文献类型：
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作者：
Hiraishi, Tomohiro;Masuda, Eriko;Maeda, Mizuo
土壤杆菌KP-2能降解和代谢热合成的高分子量的α，β-聚（D，L-天冬氨酸）（tPAA），其中含有70%的非天然β-酰胺单元。本研究对KP-2菌株PAA水解酶-1基因进行了克隆和分子生物学特性分析。基因序列分析表明，该酶推导的氨基酸序列仅与鞘氨醇单胞菌KT-1的PAA水解酶1的氨基酸序列相似。通过KP-2的PAA水解酶-1对tPAA的水解产物的GPC和NMR分析表明，该酶通过内切模式切割β-β酰胺键，从tPAA产生寡聚（天冬氨酸）。考虑到tPAA的组成和PAA水解酶-1的底物特异性，该酶可能在KP-2降解tPAA中起关键作用。
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.