Identification and sequences of the Treponema pallidum mglA and mglC genes.
Treponema pallidum, the agent of syphilis, cannot be continuously cultivated in vitro. To identify treponemal genes encoding exported proteins, we performed TnphoA mutagenesis of a T. pallidum genomic DNA library in Escherichia coli. Clone 6D2 was chosen for further study based on partial nucleotide sequence obtained from p6D2 containing a TnphoA insertion. A complete open reading frame (orf1) and a truncated orf (orf2) were identified in the treponemal DNA of p6D2. Orf1 encodes a hydrophobic protein of 531 amino acids with a calculated M(r) of 57,882 Da. The deduced amino acid sequence of Orf1 has homology to the MglC proteins of E. coli, Haemophilus influenzae, and Salmonella typhimurium. T. pallidum Orf1 (MglC) contains a conserved motif that is found in integral cytoplasmic membrane proteins of ATP-binding cassette (ABC) transport systems. T. pallidum orf2 encodes a protein of 496 amino acids with a calculated M(r) of 55,547 Da. The deduced amino acid sequence of Orf2 has homology to the MglA proteins of S. typhimurium, E. coli, H. influenzae, and Mycoplasma genitalium. Orf2 (MglA) contains two consensus ATP-binding motifs. T. pallidum mglA and mglC are located downstream of mglB, consistent with the gene order of previously identified mgl operons. The putative T. pallidum mgl operon encodes the first high-affinity ABC transport system identified in this spirochete.
Stamm
L V
LV
Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400, USA. Istamm@email.unc.edu
Young
N R
NR
Frye
J G
JG
Hardham
J M
JM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D016296:Mutagenesis; D017386:Sequence Homology, Amino Acid; D014210:Treponema pallidum / Q000235:genetics*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D008562:Membrane Glycoproteins; C489579:MglC protein, E coli; C075401:MglC protein, bacteria; D009004:Monosaccharide Transport Proteins; C071728:MglA protein, Myxococcus xanthus