摘要
分离到一株能合成γ-聚谷氨酸(γ-PGA)的细菌,通过16SrRNA 序列同源性分析、计算机微生物分类鉴定系统 BIOLOG-System 4.20等方法,确立该菌株为地衣芽孢杆菌,命名为 Bacillus licheniformis NK-03.该菌合成的γ-PGA 所含的 L-谷氨酸单体可高达98%,且重均分子量(M_w)为1360000.另外,利用 pXMJ19质粒将 B.licheniformis NK-03的7-PGA 合成酶基因 pgsBCA 克隆到了 Escherichia coli JM109中,使其成功表达合成了重均分子量为42 433的γ-PGA.同时,通过比较 B.licheniformis NK-03与已报道菌株 pgsBCA 基因编码氨基酸序列的同源性,发现基因簇中 pgsC 基因编码的氨基酸序列最为保守.
A strain of bacteria, Bacillus licheniformis NK-03, which can synthesize poly （γ-glutamic acid） （γ-PGA） was isolated and identified by 16S rRNA nucleotide sequence comparisons, Biolog-System. The content of L-glutamic acid monomer was 98 % in the γ- PGA, and the weight-average molecular weight （Mw） of γ-PGA was 1 360 000. The γ-PGA biosynthesis genes （pgsBCA） were cloned from Bacillus licheniformis NK-03. Recombinant plasmid pXMJ19-PGS was constructed by shuttle vector pXMJ19 and it was introduced into E. coli JM109. The results showed that the Mw of γ-PGA produced by E. coli recombinant was 42 433. The blast result of deduced amino acid sequence from the pgsBCA genes in B. licheniforrnis NK-03 comparing other reported strains showed that the pgsC gene is the most conservative gene for pgsBCA.
出处
《南开大学学报（自然科学版）》
CAS
CSCD
北大核心
2008年第3期57-63,共7页
Acta Scientiarum Naturalium Universitatis Nankaiensis
基金
十一.五863计划目标导向类项目(2006AA02Z239)
天津市自然科学基金(06YFJMJC07400)
南开大学2006年创新基金(Z06003-B2)
