期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 281, 期 13, 页码 8573-8581出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M513796200
关键词
-
The gene alr0617, from the cyanobacterium Anabaena sp. PCC7120, which is homologous to cpeS from Gloeobacter violaceus PCC 7421, Fremyella diplosiphon (Calothrix PCC7601), and Synechococcus sp. WH8102, and to cpcS from Synechococcus sp. PCC7002, was overexpressed in Escherichia coli. CpeS acts as a phycocyanobilin: Cys-beta 84-phycobiliprotein lyase that can attach, in vitro and in vivo, phycocyanobilin (PCB) to cysteine-beta 84 of the apo-beta-subunits of C-phycocyanin (CpcB) and phycoerythrocyanin (PecB). We found the following: ( a) In vitro, CpeS attaches PCB to native CpcB and PecB, and to their C155 I-mutants, but not to the C84S mutants. Under optimal conditions (150 mM NaCl and 500 mM potassium phosphate, 37 degrees C, and pH 7.5), no cofactors are required, and the lyase had a K-m(PCB) = 2.7 and 2.3 mu M, and a k(cat) = 1.7 x 10(-5) and 1.1 x 10(-5) s(-1) for PCB attachment to CpcB (C155I) and PecB (C155I), respectively; (b) Reconstitution products had absorption maxima at 619 and 602 nm and fluorescence emission maxima at 643 and 629 nm, respectively; and (c) PCB-CpcB(C155I) and PCB-PecB(C155I), with the same absorption and fluorescence maxima, were also biosynthesized heterologously in vivo, when cpeS was introduced into E. coli with cpcB( C155I) or pecB( C155I), respectively, together with genes ho1 ( encoding heme oxygenase) and pcyA ( encoding PCB: ferredoxin oxidoreductase), thereby further proving the lyase function of CpeS.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据