Membrane Attachment Activates dnaA Protein, the Initiation Protein of Chromosome Replication in Escherichia coli

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 85; no. 19; pp. 7202 - 7205
• Main Authors: Yung, Benjamin Yat-Ming, Kornberg, Arthur
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.10.1988; National Acad Sciences
• Subjects: Adenosine Triphosphate - metabolism; Bacterial Proteins - metabolism; Biochemistry; Cardiolipins; Cholesterol - pharmacology; Cholesterols; Chromosomes; Cysteamine - analogs & derivatives; Cysteamine - pharmacology; DNA; DNA Replication; DNA, Bacterial - biosynthesis; DnaA protein; Escherichia coli; Escherichia coli - genetics; Fatty acids; Fatty Acids, Unsaturated - analysis; inner membranes; Membrane Fluidity; Oleic Acid; Oleic Acids - pharmacology; P branes; Phospholipids; Temperature; Unsaturated fatty acids
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.19.7202

ADP and ATP are tightly bound to dnaA protein and are crucial to its function in DNA replication; the exchange of these nucleotides is effected specifically by the acidic phospholipids (cardiolipin and phosphatidylglycerol) present in Escherichia coli membranes [Sekimizu, K. & Kornberg, A. (1988) J. Biol. Chem. 263, 7131-7135]. We now find that phospholipids derived from membranes lacking an unsaturated fatty acid (e.g., oleic acid) are unable to promote the exchange. This observation correlates strikingly with the long-known effect of 3-decynoyl-N-acetylcysteamine, a ``suicide analog'' that prevents initiation of a cycle of replication in E. coli by inhibiting the synthesis of oleic acid, an inhibition that can be overcome by providing the cells with oleic acid. Profound influences on the specific binding of dnaA protein to phospholipids by temperature, the content of unsaturated fatty acids, and the inclusion of cholesterol can be explained by the need for the phospholipids to be in fluid-phase vesicles. These findings suggest that membrane attachment of dnaA protein is vital for its function in the initiation of chromosome replication in E. coli.