Molecular characterization of PcpA: a novel choline-binding protein of Streptococcus pneumoniae

• Published in: FEMS microbiology letters 1998-07, Vol.164 (1), p.207-214
• Main Authors: SANCHEZ-BEATO, A. R, LOPEZ, R, GARCIA, J. L
• Format: Article
• Language: English
• Subjects: Adhesin; Amino Acid Sequence; Amino acids; Bacterial Proteins; Bacteriology; Base Sequence; Biological and medical sciences; Blotting, Northern; Carrier Proteins - chemistry; Carrier Proteins - genetics; Choline; Choline-binding protein; Choline‐binding domain; Cloning, Molecular; E coli; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Genes, Bacterial - genetics; Humans; Leucine; Leucine‐rich repeat; Lipids; Microbiology; Molecular Sequence Data; Open Reading Frames; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Pneumococcus; Proteins; Sequence Homology, Amino Acid; Streptococcus infections; Streptococcus pneumoniae; Streptococcus pneumoniae - chemistry; Streptococcus pneumoniae - genetics; Streptococcus pneumoniae - growth & development; Transcription
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1998.tb13087.x

Abstract 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 σ70 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 amphipatic 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 finding suggests a role for PcpA in pneumococcal adhesion.