Protein and cDNA sequence data have shown human C4b-binding protein to contain eight internally homologous repeat units, each approx. 61 amino acids in length. Repeat units conforming to the same consensus sequence have been found in other complement and non-complement proteins. Southern blot analysis together with isofation, ch~racter~~tjon and sequencing of genomic clones has allowed the study of ~ntron~ exon organisation in the human C4b"binding protein gene and the identj~cation of a BgIII restriction fragment length pofymorpllism.

A 5' cDNA clone coding for human C4b-binding protein (C4bp) was isolated, characterised and sequenced to complete the cDNA sequence coding for residues 1-32 thus confirming the protein sequence data of Chung et al. [(1985) Biochem. J. 230, 133%1411. The sequence extended to allow derivation of the putative leader peptide sequence which was 32 residues in length and showed a high of hydrophobicity typical of other documented leader sequences. Cross hybridisation was detected between the human C4bp cDNA probes and genomic DNA isolated from various species on Southern blots suggesting that genomic sequence. homologous to that coding for C4bp has been conserved during evolution.

No abstract