天蓝色链霉菌氧化酶（SCO2837p）：一种由天蓝色链霉菌A3(2)分泌的新型自由基金属酶。

Streptomyces coelicolor oxidase (SCO2837p): a new free radical metalloenzyme secreted by Streptomyces coelicolor A3(2).

作者信息

Whittaker Mei M, Whittaker James W

机构信息

Department of Environmental and Biomolecular Systems, Oregon Health and Science University, Beaverton, OR 97006-8291, USA.

出版信息

Arch Biochem Biophys. 2006 Aug 15;452(2):108-18. doi: 10.1016/j.abb.2006.06.020. Epub 2006 Jul 10.

DOI:10.1016/j.abb.2006.06.020

PMID:16884677

Abstract

The SCO2837 open-reading frame is located within the conserved central core region of the Streptomyces coelicolor A3(2) genome, which contains genes required for essential cellular functions. SCO2837 protein (SCO2837p) expressed by Pichia pastoris is a copper metalloenzyme, catalyzing the oxidation of simple alcohols to aldehydes and reduction of dioxygen to hydrogen peroxide. Distinct optical absorption spectra are observed for oxidized and one-electron reduced holoenzyme, and a free radical EPR signal is present in the oxidized apoprotein, characteristic of the Tyr-Cys redox cofactor previously reported for fungal secretory radical copper oxidases, galactose oxidase and glyoxal oxidase, with which it shares weak sequence similarity. SCO2837p was detected in the growth medium of both S. coelicolor and a recombinant expression host (Streptomyces lividans TK64) by Western blotting, with the expression level dependent on the nature of the carbon source. This represents the first characterized example of a prokaryotic radical copper oxidase.

摘要

SCO2837开放阅读框位于天蓝色链霉菌A3(2)基因组保守的中央核心区域内，该区域包含细胞基本功能所需的基因。毕赤酵母表达的SCO2837蛋白（SCO2837p）是一种铜金属酶，催化简单醇类氧化为醛类以及将双原子氧还原为过氧化氢。氧化型和单电子还原型全酶呈现出不同的光吸收光谱，并且在氧化型脱辅基蛋白中存在自由基EPR信号，这是先前报道的真菌分泌型自由基铜氧化酶、半乳糖氧化酶和乙二醛氧化酶的酪氨酸-半胱氨酸氧化还原辅因子的特征，SCO2837p与它们具有较弱的序列相似性。通过蛋白质免疫印迹法在天蓝色链霉菌和重组表达宿主（变铅青链霉菌TK64）的生长培养基中均检测到了SCO2837p，其表达水平取决于碳源的性质。这是原核生物自由基铜氧化酶的首个经表征的实例。