摘要
含有大肠杆菌青霉素G酰化酶基因的质粒pWGA在菌株DH5α中表达时,表现为温度敏感。在30℃和37℃两种培养温度下,用Northern Blot和Western Blot研究了菌体的转录水平和翻译水平。结果表明菌体培养温度升高不影响mRNA的转录,但不利于青霉素酰化酶前体蛋白的正确加工,导致青霉素酰化酶在37℃发酵生产时酶活力单位的下降。
The expression of penicillin G acylase (PGA) gene is sensitive to temperature. Cells of E. coli DH 5a harboring a plasmid pWGA carrying a gene for PGA produce active PGA at low level at 37℃ but can synthesize significant amount of the enzyme below 30℃. Active PGA is formed from a 94 KD precusor processed through remove of a signal peptide and a spacer peptide to yield an enzyme that contain a 23 KD (α) and 65 KD (β) subunit. This paper reported the effect of temperature on transcription, translation, and post-translational processing of PGA gene expression. We detected the transcription of PGA gene by Northern blet, and found the amount cf PGA mRNA at 37℃ much more than that 30℃ when the cells of DH 5α (pWGA) were cultured. It is evident that the precusor processing step(s) is sensitive to temperature.
出处
《实验生物学报》
CSCD
1991年第1期55-58,共4页
Acta Biologiae Experimentalis Sinica
关键词
大肠杆菌
青霉素酰化酶
基因表达
Penicillin G acylase. Precusor processing. Gene expression.
