球形红杆菌细胞色素c2在大肠杆菌中的合成。

Synthesis of Rhodobacter sphaeroides cytochrome c2 in Escherichia coli.

作者信息

McEwan A G, Kaplan S, Donohue T J

机构信息

Department of Microbiology, University of Illinois, Urbana.

出版信息

FEMS Microbiol Lett. 1989 Jun;50(3):253-8. doi: 10.1016/0378-1097(89)90427-8.

DOI:10.1016/0378-1097(89)90427-8

PMID:2547689

Abstract

The cytochrome c2 structural gene, cycA, from Rhodobacter sphaeroides was expressed in Escherichia coli. CycA-specific mRNA was detected in E. coli both under aerobic and anaerobic conditions with trimethylamine-N-oxide as electron acceptor. However mature holocytochrome c2 was only detected in anaerobically-grown cells. The mature form of cytochrome c2 (Mr = 12,500) was secreted into the periplasm of E. coli suggesting that the signal polypeptide was processed. The cytochrome c2 synthesized in E. coli exhibited absorbance maxima in the reduced form at 550 nm (alpha-band) and 521 nm (beta-band) and contained covalently attached haem c. The results indicate that a foreign c-type cytochrome can be secreted and assembled in E. coli under anaerobic conditions.

摘要

来自球形红杆菌的细胞色素c2结构基因cycA在大肠杆菌中得到表达。在以三甲胺-N-氧化物作为电子受体的有氧和无氧条件下，均在大肠杆菌中检测到了cycA特异性mRNA。然而，仅在厌氧生长的细胞中检测到了成熟的全细胞色素c2。细胞色素c2的成熟形式（Mr = 12,500）分泌到大肠杆菌的周质中，这表明信号多肽已被加工。在大肠杆菌中合成的细胞色素c2在还原形式下于550 nm（α带）和521 nm（β带）处呈现吸光度最大值，并且含有共价连接的血红素c。结果表明，一种外源c型细胞色素能够在厌氧条件下在大肠杆菌中分泌并组装。