PORIN ACTIVITY OF PURIFIED LAMBDA-RECEPTOR PROTEIN FROM ESCHERICHIA-COLI IN RECONSTITUTED VESICLE MEMBRANES

The receptor protein for bacteriophage λ was purified to homogeneity from a mutant strain of Escherichia coli K-12 producing reduced amounts of porin. In the reconstituted vesicle membranes the λ-receptor formed permeability channels that allowed the diffusion of maltose, lactose, sucrose, raffinose, amino acids, and nucleosides, but essentially not of stachyose. The permeability channels made of λ-receptor thus had a relatively low specificity for solute molecules. The active form of the protein seemed to be an oligomer of λ-receptor proteins. © 1979.