Effect of Export-Specific Cytoplasmic Chaperone, Protein SecB, on Secretion of Escherichia coli Alkaline Phosphatase

S. V. Kononova¹, O. V. Khokhlova², S. N. Zolov¹, and M. A. Nesmeyanova^1*

¹Skryabin 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

²Pushchino State University, Pushchino, Moscow Region, 142290 Russia; fax: (095) 956-3370; E-mail: priem@adm.pgu.serpukhov.su

^* To whom correspondence should be addressed.

Received January 11, 2001; Revision received April 1, 2001

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The efficiency of secretion of Escherichia coli alkaline phosphatase depends on the presence in cells of a cytoplasmic chaperone--protein SecB. Secretion increases in the presence of this chaperone at 30°C, which is the most favorable for the interaction of SecB with the export-initiation domain found previously in the N-terminal region of the mature enzyme. This interaction most likely occurs in the region of the export domain, which is located close to the signal peptide and in complex with a translocational ATPase--protein SecA.

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KEY WORDS: Escherichia coli, alkaline phosphatase, protein translocation, export domain, amino acid substitutions, chaperone SecB, protein SecA

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