Studies on the sequence and structure of the Escherichia coli K‐12 nupG gene, encoding a nucleoside‐transport system

Abstract

The nupG gene, encoding one of the two active nucleoside‐transport systems in Escherichia coli K‐12, has been cloned on the multicopy plasmid pBR322 and derivatives thereof. The recombinant plasmids complemented a chromosomal nupG mutation. A genetic map was determined by digestion with restriction endonucleases and the nucleotide sequence of a 3‐kb stretch of DNA has been determined on fragments cloned into M13 phages. An open reading frame of 1254 bp, encoding a protein with a calculated molecular mass of 45.333 kDa, was deduced to be the coding region of nupG. Minicell‐forming strains carrying plasmids containing this gene were shown to produce a hydrophobic, membrane‐bound polypeptide with an apparent molecular mass of approximately 43 kDa. Copyright © 1987, Wiley Blackwell. All rights reserved