Masui R, Wakabayashi S, Matsubara H, Hatefi Y
Department of Biology, Faculty of Science, Osaka University.
J Biochem. 1991 Apr;109(4):534-43. doi: 10.1093/oxfordjournals.jbchem.a123416.
Mitochondrial NADH:ubiquinone oxidoreductase (complex I) is the most complicated system in the respiratory chain. It consists of many subunits, some of which hold iron-sulfur clusters, but structural information is still limited. The amino acid sequences of two 13 kDa polypeptides, 13 kDa-A and 13 kDa-B polypeptides, of iron-sulfur protein fraction (IP) of bovine heart mitochondrial complex I were determined by a combination of protease digestion, Edman degradation, and carboxypeptidase digestion. The 13 kDa-A polypeptide was composed of 96 amino acids with a molecular weight of 10,536. The 13 kDa-B polypeptide consisted of 114 amino acids and had an acetylated amino terminus. The molecular weight of this protein was calculated to be 13,130 including the acetyl group. These proteins had no obvious sequence similarity to other known proteins. The partial amino acid sequence of 30 kDa-B polypeptide of IP was also determined to reveal a characteristic arrangement of cysteine residues that could be involved in iron-sulfur cluster formation.
线粒体NADH：泛醌氧化还原酶（复合体I）是呼吸链中最复杂的系统。它由许多亚基组成，其中一些含有铁硫簇，但结构信息仍然有限。通过蛋白酶消化、埃德曼降解和羧肽酶消化相结合的方法，确定了牛心线粒体复合体I的铁硫蛋白组分（IP）中两种13 kDa多肽（13 kDa-A和13 kDa-B多肽）的氨基酸序列。13 kDa-A多肽由96个氨基酸组成，分子量为10536。13 kDa-B多肽由114个氨基酸组成，氨基末端有乙酰化修饰。该蛋白包括乙酰基在内的分子量经计算为13130。这些蛋白质与其他已知蛋白质没有明显的序列相似性。还确定了IP的30 kDa-B多肽的部分氨基酸序列，以揭示可能参与铁硫簇形成的半胱氨酸残基的特征排列。
