Multiple Posttranslational Modifications at Distinct Sites Contribute to Heterogeneity of the Lipoprotein Cytochrome bo3

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• 作者：Alexander Prutsch ; Christiane Lohaus ; Brian Green ; Helmut E. Meyer ; and Mathias L&uuml ; bben
• 刊名：Biochemistry
• 出版年：2000
• 出版时间：May 30, 2000
• 年：2000
• 卷：39
• 期：21
• 页码：6554 - 6563
• 全文大小：148K
• 年卷期：v.39,no.21(May 30, 2000)
• ISSN：1520-4995

文摘

The heme-copper cytochrome oxidase of Escherichia coli (cytochrome bo₃) was tagged witholigohistidine at the C-terminus of the small noncatalytic subunit IV. After detergent solubilization, theenzyme was purified by a one-step procedure with immobilized metal affinity chromatography. Usingdifferent cytochrome bo₃ constructs as reference, the products were investigated by mass spectroscopicaland immunological methods. Several posttranslational modifications of subunits II, III, and IV wereobserved: (1) N-terminal methionines of subunits III and IV are split off. (2) Fifty percent of subunit IIIpolypeptides are acetylated, presumably at the N-terminal alanine. (3) Lipoprotein processing of subunitII involves cleavage of the signal peptide. (4) Maturation of subunit II [Ma, J., Katsonouri, A., and Gennis,R. B. (1997) Biochemistry 36, 11298-11303] alters the structure of the N-terminal cysteine byN-palmitoylation and S-glyceryldipalmitoylation. (5) A hexapeptide is split off from the C-terminus ofsubunit II. This happens subsequently to the N-terminal lipoprotein processing step and is dependent onthe growth state of cells.