锌（II）在大肠杆菌B的DNA依赖性RNA聚合酶中的亚基定位。

Subunit localizations of zinc(II) in DNA-dependent RNA polymerase from Escherichia coli B.

作者信息

Miller J A, Serio G F, Howard R A, Bear J L, Evans J E, Kimball A P

出版信息

Biochim Biophys Acta. 1979 Aug 28;579(2):291-7. doi: 10.1016/0005-2795(79)90056-4.

Abstract

RNA Polymerase holoenzyme and core enzyme from Escherichia coli B have been shown to contain two zinc ions. Flameless atomic absorption spectroscopy of the isolated core subunits indicated that one zinc ion is localized on the beta subunit and the other is bound on the beta' subunit. Atomic fluorescence spectroscopy showed that prolonged dialysis of the metalloenzyme against 0.01 M o-phenanthroline resulted in the removal of both zinc(II) ions with accompanying loss of enzymatic activity. The activity of the apoenzyme was observed to be completely restored by readdition of zinc(II) and partially restored by cobalt(II).

摘要

已证明来自大肠杆菌B的RNA聚合酶全酶和核心酶含有两个锌离子。对分离出的核心亚基进行无火焰原子吸收光谱分析表明，一个锌离子定位于β亚基上，另一个与β'亚基结合。原子荧光光谱显示，金属酶用0.01 M邻菲罗啉长时间透析会导致两个锌（II）离子被去除，同时酶活性丧失。观察到通过重新添加锌（II）可使脱辅基酶的活性完全恢复，而钴（II）可使其部分恢复。