title: Expression and regulation of protein K, an Escherichia coli K1 porin, in Escherichia coli K-12.
abstract: 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 K1 strain to an E coli K-12 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 125I-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 envZ-473 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.
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification; D013045:Species Specificity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins; C021076:protein K