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Daring to be different: colicin N finds another way
Author(s) -
Jakes Karen S.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12569
Subject(s) - colicin , bacterial outer membrane , porin , biology , escherichia coli , receptor , microbiology and biotechnology , biochemistry , gene
Summary The mechanisms by which colicins, protein toxins produced by E scherichia coli , kill other E . coli , have become much better understood in recent years. Most colicins initially bind to an outer membrane protein receptor, and then search for a separate nearby outer membrane protein translocator that serves as a pathway into target cells. Many colicins use the outer membrane porin, OmpF , as that translocator, while using a different primary receptor. Colicin N is unique among known colicins in that only OmpF had been identified as being required for uptake of the colicin and it was presumed to somehow serve as both receptor and translocator. Genetic screens also identified a number of genes required for lipopolysaccharide ( LPS ) synthesis as uniquely required for killing by colicin N , but not by other colicins. J ohnson et al . show that the receptor‐binding domain of colicin N binds to LPS , and does not require OmpF for that binding. LPS of a minimal length is required for binding, explaining the requirement for specific elements of the LPS biosynthetic pathway. For colicin N , the receptor‐binding domain does not recognize a protein, but rather the most abundant component of the outer membrane itself, LPS .