Characterization of lipid-modified immunogenic proteins of Treponema pallidum expressed in Escherichia coli.
This study describes the sequence of the immunodominant Treponema pallidum surface protein TpD and its expression in Escherichia coli. The translated TpD DNA sequence revealed the presence of a putative site for lipid-modification downstream from the signal sequence of this membrane protein. Growth of TpD-expressing E. coli in the presence of radioactive palmitic acid revealed that TpD was lipid-modified. Three other, previously characterized cloned proteins of T. pallidum were also lipid-modified. The N-termini of two of three sequenced T. pallidum proteins contain a tetrapeptide sequence characteristic for lipoproteins in Gram-negative bacteria: Leu-X-Y-Cys. Only TpD differed from this consensus sequence in the substitution of the first residue by Phe. The apparent high incidence of lipoproteins among E. coli recombinants expressing T. pallidum antigens suggest an important role of lipoproteins in the induction of humoral immunity during syphilitic infection.
Schouls
L M
LM
Laboratory for Bacteriology, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
Mout
R
R
Dekker
J
J
van Embden
J D
JD
D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D008565:Membrane Proteins; D010169:Palmitic Acids / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011499:Protein Processing, Post-Translational; D014210:Treponema pallidum / Q000235:genetics / Q000378:metabolism*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D010169:Palmitic Acids; C062634:TpD protein, Treponema pallidum