Abstract |
Automated Edman degradation was used to obtain N-terminal and internal amino acid sequences from a 26-kDa protein in isolated Treponema pallidum outer membranes (OMs). The resulting sequences enabled us to PCR amplify from T. pallidum DNA a 275-bp fragment of the corresponding gene. The complete nucleotide sequence of the gene was determined from fragments amplified by long-distance PCR. Primer extension verified the assigned translational start of the open reading frame (ORF) and putative upstream promoter elements. The ORF encoded a highly basic (pI 9.6) 26-kDa protein which contained an N-terminal 25-amino-acid leader peptide terminated by a signal peptidase I cleavage site. The mature protein contained seven tandemly spaced copies (as well as an eighth incomplete copy) of a leucine-rich repeat (LRR), a motif previously identified in a number of prokaryotic and eukaryotic proteins. Accordingly, the polypeptide was designated T. pallidum leucine-rich repeat protein (TpLRR). Although Triton X-114 phase partitioning showed that TpLRR was hydrophilic, cell localization studies showed that most of the antigen was associated with the peptidoglycan-cytoplasmic membrane complex rather than being freely soluble in the periplasmic space. Immunoblot studies showed that syphilis patients develop a weak antibody response to the antigen. Lastly, the lrr(T. pallidum) gene was mapped to a 60-kb SfiI-SpeI fragment of the T. pallidum chromosome which also contains the rrnA and flaA genes. The function(s) of TpLRR is currently unknown; however, protein- protein and/or protein- lipid interactions mediated by its LRR motifs may facilitate interactions between components of the T. pallidum cell envelope.
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Authors | D V Shevchenko, D R Akins, E Robinson, M Li, T G Popova, D L Cox, J D Radolf |
Journal | Journal of bacteriology
(J Bacteriol)
Vol. 179
Issue 10
Pg. 3188-95
(May 1997)
ISSN: 0021-9193 [Print] United States |
PMID | 9150213
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Antibodies, Bacterial
- Bacterial Outer Membrane Proteins
- Peptidoglycan
- TpLRR protein, Treponema pallidum
- Leucine
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Topics |
- Amino Acid Sequence
- Antibodies, Bacterial
(biosynthesis)
- Bacterial Outer Membrane Proteins
(chemistry, genetics, isolation & purification)
- Base Sequence
- Cell Membrane
(chemistry, genetics)
- Chromosome Mapping
- Cytoplasm
(chemistry)
- Leucine
(metabolism)
- Molecular Sequence Data
- Peptidoglycan
(chemistry)
- Protein Structure, Secondary
- Repetitive Sequences, Nucleic Acid
- Syphilis
(microbiology)
- Treponema pallidum
(chemistry, genetics)
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