The Major Phospholipid of Escherichia coli, Phosphatidylethanolamine, Is Required for Efficient Production and Secretion of Alkaline Phosphatase

V. V. Golovastov, N. I. Mikhaleva, L. Yu. Kadyrova, and M. A. Nesmeyanova^*

Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia; fax: (095) 923-3602; E-mail: aniram@ibpm.serpukhov.su

^* To whom correspondence should be addressed.

Received February 3, 2000; Revision received May 10, 2000

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The major phospholipid of the Escherichia coli membranes--the zwitterion phosphatidylethanolamine (PE)--is the only phospholipid involved in the formation of non-bilayer structure of membrane lipids, which is supposed to be necessary for efficient translocation of secreted proteins across the cytoplasmic membrane. The effect of PE on the production and secretion of alkaline phosphatase has been studied in this work using the mutant strain E. coli AD93, which is unable to synthesize PE. It was shown that this phospholipid is required for the efficient production and secretion of alkaline phosphatase. The anionic phospholipid cardiolipin in combination with divalent cations Mg²⁺ functionally replaces PE in these processes, participating in the regulation of lipid polymorphism.

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KEY WORDS: proteins, secretion, phospholipids, bacteria, Escherichia coli, phospholipid mutations

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