Amino acid sequence homologies and glycosylation differences between the fourth component of murine complement and sex-limited protein.

AUTOR(ES)

Karp, D R

RESUMO

Limited primary sequence data have been obtained for all three subunits of the fourth component of murine complement (C4) and its related homologue, the sex-limited protein (Slp). These data show a high degree of NH2-terminal homology between C4 and Slp: four of the six residues identified for the alpha chain, seven of eight for the beta chain, and four of four for the gamma chain. This suggests that apparent molecular weight differences between C4 and Slp subunits are not, as previously suggested, due to a shift in the proteolytic processing sites in the pro-Slp polypeptide molecule. Chemical deglycosylation (apparently complete) of the C4 and Slp alpha chains with trifluoromethanesulfonic acid removes the molecular weight difference between them, suggesting that acquisition of extra glycosylation sites in the latter is responsible for this difference.

Documentos Relacionados

• Sequence comparison of alleles of the fourth component of complement (C4) and sex-limited protein (Slp).
• Isolation of cDNA clones specifying the fourth component of mouse complement and its isotype, sex-limited protein.
• Murine complement component C4 and sex-limited protein: identification of amino acid residues essential for C4 function.
• Genes for murine fourth complement component (C4) and sex-limited protein (Slp) identified by hybridization to C4- and Slp-specific cDNA.
• Structural characterization of the murine fourth component of complement and sex-limited protein and their precursors: Evidence for two loci in the S region of the H-2 complex