| 17169576 |
Gourdine JP, Smith-Ravin EJ: Analysis of a cDNA-derived sequence of a novel mannose-binding lectin, codakine, from the tropical clam Codakia orbicularis. Fish Shellfish Immunol. 2007 May;22(5):498-509. Epub 2006 Jul 10.
This work relates to the characterisation of the predominant gill protein of the white clam, Codakia orbicularis (Linne, 1758), which harbours endosymbiotic sulphur-oxidising chemoautotrophic bacteria. Total RNA was extracted from the clam to perform 3'rapid amplification of cDNA ends (3'RACE) using degenerate oligonucleotides prepared from a partial sequence of a predominant protein of about 14kDa, termed codakine. The partial peptide sequence was obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and Edman degradation. Clones isolated from the cDNA library and containing the gene of interest were used in polymerase chain reaction (PCR). The PCR and RACE-PCR products were sequenced to determine the entire coding DNA sequence of codakine. BLAST analysis revealed about 23% to 29% sequence identity between codakine and various animal C-type lectins that are often involved in symbiosis and immune defences. Codakine also contains the motifs and domains of Ca (2+)-dependent C-type lectins, and in particular the tripeptide EPN motif frequently found in mannose-binding lectins (MBLs). Analysis of the protein by affinity chromatography on a mannose-agarose column is consistent with the findings that codakine is a dimeric Ca (2+)-dependent MBL of about 29kDa. Based on the present results, it is hypothesised that this novel C. orbicularis gill protein is involved in the recognition of symbiotic and pathogenic bacteria. |
2(0,0,0,2) |