ISOLATION OF A GENE ENCODING NODULIN-LIKE INTRINSIC PROTEIN OF ESCHERICHIA-COLI

Members of the membrane intrinsic protein (MIP) family are expressed i n various organisms including plants, insects, and vertebrates. E. col i is known to have a MIP member gene, glycerol facilitator (GlpF). Her e we report the isolation of E. coli gene encoding BniP, bacterial nod ulin-like intrinsic protein. BniP encodes a 231 amino acid, 24 kDa pro tein with 42 % amino acid identity to Nod26, 38 % amino acid identity to AQP1, and 29 % amino acid identity to GlpF. Analysis of deduced ami no acid sequence predicted a hydrophobic protein with six membrane-spa nning domains. Expression of BniP in Xenopus oocytes induced slight in crease in osmotic water permeability, but not glycerol or ion permeabi lity. Our results showed that BniP is a new member of the MIP channel- forming proteins of E. coli.