食品与发酵工业2024，Vol.50Issue(12)：9-16,8.DOI:10.13995/j.cnki.11-1802/ts.035737
新型高丝氨酸脱氢酶的挖掘与改造研究
Research on mining and evolution of a novel homoserine dehydrogenase
摘要
Abstract
Homoserine dehydrogenase(HSD)is a key enzyme in the biosynthesis of aspartate-family amino acids such as L-homo-serine and L-threonine.But HSD exhibited low activity and is feedback inhibited by L-threonine,which severely restricts the biosynthesis level of L-homoserine and L-threonine.In this study,eight HSDs from different species were mined through database search.Among of them,BdHSD derived from Brachypodium distachyon had the highest catalytic activity with 7.6 U/mg,and was not feedback-inhibited by L-threonine.The optimal catalytic pH of BdHSD was 10.5,and the optimal catalytic temperature was 38 ℃.To improve the catalytic activ-ity of BdHSD,this study further performed the directed evolution of BdHSD,and three BdHSD mutants T186A,N283K,and A137T/I188V with higher catalytic activity were obtained through multiple rounds of screening.The enzyme activity of the mutant T186A reached 10.3 U/mg,which was 35.6％higher than that of the wild type.The L-homoserine fermentation analysis suggested that the BdHSD mutant could effectively enhance the synthesis level of L-homoserine.In summary,this study had mined and evolved the BdHSD with high efficient catalytic,which provided a powerful catalytic element for the efficient biosynthesis of L-homoserine,L-threonine,L-methionine,and other aspartate-family amino acids.关键词
高丝氨酸脱氢酶/酶进化/二穗短柄草/L-高丝氨酸/抗苏氨酸Key words
homoserine dehydrogenase/enzyme evolution/Brachypodium distachyon/L-homoserine/anti-threonine引用本文复制引用
吴硕,黄新燕,李梦雅,徐宁,魏亮,刘君..新型高丝氨酸脱氢酶的挖掘与改造研究[J].食品与发酵工业,2024,50(12):9-16,8.基金项目
国家重点研发计划(2021YFC2100700) （2021YFC2100700）
国家自然科学基金(32001671,31972061) （32001671,31972061）
