AN L-ARABINOSE BINDING PROTEIN AND ARABINOSE PERMEATION IN ESCHERICHIA COLI

A search was made for proteins of the arabinose system which bind arabinose, as it is expected that the permease and possibly the C protein could be identified by arabinose binding. One protein was found and this is most probably part of the arabinose permease. It is inducible, can be removed from cells by osmotic shock and easily purified, and consists of one polypeptide of molecular weight 35,000. In these respects it is closely similar to proteins binding sulfate, leucine, and galactose (Pardee, Prestidge, Whipple & Dreyfuss, 1966; Anraku, 1968; Penrose, Nichoalds, Piperno & Oxender, 1968). Mutants were found with reduced ability to concentrate arabinose intracellularly but which still possessed the arabinose binding proteins. One mutant was found with a lowered level of binding protein. This strain is unable to concentrate any detectable amount of arabinose. None of the mutations affecting permeation of arabinose mapped in the threonine-leucine region where the arabinose genes A, B, C and D are located. © 1969.