This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Boehler-Kohler, B A Articles by Benz, R Search for Related Content PubMed PubMed Citation Articles by Boehler-Kohler, B A Articles by Benz, R

Receptor for bacteriophage lambda of Escherichia coli forms larger pores in black lipid membranes than the matrix protein (porin).

ABSTRACT

The receptor for phage lambda in Escherichia coli was isolated by cholate extraction and purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Protein bands corresponding to the monomer and the dimer were eluted from the gel and tested for their activity to inactivate phage lambda and to form pores in black lipid membranes. It was found that only the dimer inactivated phage lambda, whereas both the monomer and the dimer were active in forming pores. The pore characteristics were similar to those exhibited by the matrix protein (porin) (R. Benz, K. Janko, W. Boos, and P. Läuger, Biochim. Biophys. Acta 511:305--319, 1978). In comparison, the lambda receptor showed a somewhat higher degree of cation specificity, and its pore size was larger. Assuming that the thickness of the outer membrane is 7.5 nm and that the pore is an ideal hydrophilic channel, the pore diameter in vivo was estimated to be 1.6 nm for the lambda receptor and 1.2 nm for the matrix protein.