Long C M, Rohrmann G F, Merrill G F
Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.
Virology. 2009 Jun 5;388(2):231-5. doi: 10.1016/j.virol.2009.04.006. Epub 2009 May 1.
Open reading frame 92 of the Autographa californica baculovirus (Ac92) is one of about 30 core genes present in all sequenced baculovirus genomes. Computer analyses predicted that the Ac92 encoded protein (called p33) and several of its baculovirus orthologs were related to a family of flavin adenine dinucleotide (FAD)-linked sulfhydryl oxidases. Alignment of these proteins indicated that, although they were highly diverse, a number of amino acids in common with the Erv1p/Alrp family of sulfhydryl oxidases are present. Some of these conserved amino acids are predicted to stack against the isoalloxazine and adenine components of FAD, whereas others are involved in electron transfer. To investigate this relationship, Ac92 was expressed in bacteria as a His-tagged fusion protein, purified, and characterized both spectrophotometrically and for its enzymatic activity. The purified protein was found to have the color (yellow) and absorption spectrum consistent with it being a FAD-containing protein. Furthermore, it was demonstrated to have sulfhydryl oxidase activity using dithiothreitol and thioredoxin as substrates.
苜蓿银纹夜蛾核型多角体病毒（Ac92）的开放阅读框92是所有已测序杆状病毒基因组中约30个核心基因之一。计算机分析预测，Ac92编码的蛋白质（称为p33）及其一些杆状病毒直系同源物与黄素腺嘌呤二核苷酸（FAD）连接的巯基氧化酶家族有关。这些蛋白质的比对表明，尽管它们高度多样，但仍存在一些与Erv1p/Alrp巯基氧化酶家族共有的氨基酸。预计其中一些保守氨基酸会与FAD的异咯嗪和腺嘌呤成分堆积，而其他氨基酸则参与电子转移。为了研究这种关系，Ac92在细菌中作为His标签融合蛋白表达、纯化，并通过分光光度法和酶活性进行了表征。发现纯化后的蛋白质的颜色（黄色）和吸收光谱与它是一种含FAD的蛋白质一致。此外，以二硫苏糖醇和硫氧还蛋白为底物，证明其具有巯基氧化酶活性。
