title: LcrD, a membrane-bound regulator of the Yersinia pestis low-calcium response.
abstract: Yersinia pestis, the etiologic agent of bubonic plague, contains a 75-kb virulence plasmid, called pCD1 in Y. pestis KIM. The low-Ca(2+)-response genes of Y. pestis regulate both bacterial growth and the expression of pCD1-encoded virulence determinants in response to temperature and the presence of Ca2+ or nucleotides. This study characterizes the nucleotide sequence and protein product of the lcrD locus. An lcrD mutant, in contrast to the parent Y. pestis, did not undergo growth restriction or induce strong expression of the V antigen when grown under conditions (37 degrees C, no Ca2+) expected to elicit maximal expression of pCD1 genes. DNA sequence analysis of the cloned lcrD locus showed a single open reading frame that could encode a protein with a molecular weight of 77,804 and a pI of 4.88. LcrD was identified as a 70-kDa inner membrane protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis. LcrD membrane topology was investigated by using lcrD-phoA translational fusions generated with the transposon TnphoA. The alkaline phosphatase activities of the resultant hybrid proteins were consistent with a model predicting eight amino-terminal transmembrane segments that anchor a large cytoplasmic carboxyl-terminal domain to the inner membrane.
authors.affiliation: Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536.
authors.forename: G V
authors.initials: GV
authors.lastname: Plano
authors.forename: S S
authors.initials: SS
authors.lastname: Barve
authors.forename: S C
authors.initials: SC
authors.lastname: Straley
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology*; D002462:Cell Membrane / Q000648:ultrastructure; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification; D008961:Models, Structural; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D010957:Plasmids; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics; D015010:Yersinia pestis / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C071579:LcrD protein, Yersinia; D000469:Alkaline Phosphatase; D002118:Calcium