Study of Interaction of Export Initiation Domain of Escherichia coli Mature Alkaline Phosphatase with Membrane Phospholipids during Secretion

V. V. Golovastov, S. N. Zolov, and M. A. Nesmeyanova^*

Laboratory of Protein Secretion in Bacteria, Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia; fax: (095) 956-3370; E-mail: aniram@ibpm.serpukhov.su

^* To whom correspondence should be addressed.

Received February 1, 2002

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The efficiency of secretion of alkaline phosphatase from Escherichia coli depending on the primary structure of its N-terminal region and the content of zwitterionic phospholipid phosphatidylethanolamine and anionic phospholipids in membranes has been studied in this work to establish the peculiarities of interaction of mature protein during its secretion with membrane phospholipids. It has been shown that the effect of phosphatidylethanolamine but not anionic phospholipids on the efficiency of alkaline phosphatase secretion is determined by the primary structure of its N-terminal region. The absence of phosphatidylethanolamine appreciably reduces the efficiency of secretion of wild type alkaline phosphatase and its mutant forms with amino acid substitutions in positions +5+6 and +13+14. In contrast, secretion of the protein withamino acid substitutions in positions +2+3, significantly decreased as a result of such mutation, in the presence of phosphatidylethanolamine, reaches the level of wild type protein secretion in the absence of phosphatidylethanolamine. The results suggest an interaction of the N-terminal region of the mature protein under its translocation across the membrane with phosphatidylethanolamine.

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KEY WORDS: alkaline phosphatase, protein secretion, phospholipids, amino acid substitutions, SecA, Escherichia coli

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