title: Nucleotide sequence and analysis of the mgl operon of Escherichia coli K12.
abstract: The nucleotide sequence of the Escherichia coli K12 beta-methylgalactoside transport operon, mgl, was determined. Primer extension analysis indicated that the synthesis of mRNA initiates at guanine residue 145 of the determined sequence. The operon contains three open reading frames (ORF). The operator proximal ORF, mglB, encodes the galactose binding protein, a periplasmic protein of 332 amino acids including the 23 residue amino-terminal signal peptide. Following a 62 nucleotide spacer, the second ORF, mglA, is capable of encoding a protein of 506 amino acids. The amino-terminal and carboxyl-terminal halves of this protein are homologous to each other and each half contains a putative nucleotide binding site. The third ORF, mglC, is capable of encoding a hydrophobic protein of 336 amino acids which is thought to generate the transmembrane pore. The overall organization of the mglBAC operon and its potential to encode three proteins is similar to that of the ara FGH high affinity transport operon, located approximately 1 min away on the E. coli K12 chromosome.
authors.affiliation: Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106.
authors.forename: R W
authors.initials: RW
authors.lastname: Hogg
authors.forename: C
authors.initials: C
authors.lastname: Voelker
authors.forename: I
authors.initials: I
authors.lastname: Von Carlowitz
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005697:Galactosides / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D016366:Open Reading Frames; D009876:Operon; D033902:Periplasmic Binding Proteins; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping
chemical_list: D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D005697:Galactosides; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; C007816:beta-galactoside; C023550:galactose-binding protein