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Expression and regulation of protein K, an Escherichia coli K1 porin, in Escherichia coli K‐12
Author(s) -
Sutcliffe Joyce A.,
Foulds John D.
Publication year - 1983
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240230108
Subject(s) - escherichia coli , porin , biology , strain (injury) , gene , microbiology and biotechnology , osmotic concentration , fusion protein , lambda phage , insert (composites) , biochemistry , bacterial outer membrane , bacteriophage , recombinant dna , mechanical engineering , anatomy , engineering
Using a modified lambda phage as a vector and a procedure developed in Dr. C. Schnaitman's laboratory, we have cloned the structural gene for protein K from an Escherichia coli KI strain to an E coli K‐I2 strain. The cloned inserts consist of two HindIII fragments, 4 kb and 6.5 kb in size. The protein produced by the insert is nearly identical to “authentic” protein K when chymotryptic peptides of 125 I‐labeled proteins are compared. Protein K was found to respond to changes in the osmolarity of the medium, being favored in trypticase soy broth (high osmolarity). This fluctuation was not dependent on a functional ompR gene. However, protein K was not expressed in strains carrying the envZ473 mutation. Thus, protein K appears to be within a class of exported proteins whose expression is regulated by the envZ gene independent of the ompR gene.