Molecular characterization of PcpA: a novel choline-binding protein of Streptococcus pneumoniae.
The gene pcpA that encodes a novel pneumococcal choline-binding protein has been cloned and characterized. Northern blot analysis revealed that pcpA is expressed during the exponential phase of growth of pneumococci as a monocistronic transcript of about 2.3 kb. The transcription start site has been located 132 bp upstream of the start codon and the proposed -35 and -10 boxes that are highly similar to those of the typical sigma 70 promoters from Escherichia coli. This gene encodes a putative 79 kDa protein that contains a typical C-terminal choline-binding domain (ChBD). The ChBD of PcpA is built up by 11 identical motifs of 20 amino acids plus a tail of 19 amino acids, which represents the longest ChBD that has been characterized so far. Interestingly, two tandem arrays of five characteristic amphipathic leucine reach repeats (LRRs) of 22-26 amino acids in length have been found in the N-terminal region of PcpA. Since LRRs have been proposed to be involved in protein-protein and protein-lipid interactions our findings suggests a role for PcpA in pneumococcal adhesion.
Department of Molecular Microbiology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
A R
AR
Sánchez-Beato
R
R
López
J L
JL
García
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development
D001426:Bacterial Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C113653:PcpA protein, Streptococcus