Nucleotide and corrected amino acid sequence of the functional recombinant rat anaphylatoxin C5a.

For bacterial expression of rat anaphylatoxin C5a, the cDNA was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) using rat liver RNA and degenerate primers designed according to the published amino acid sequence [1]. Surprisingly, the amino acid sequence deduced from cDNA differed at positions 55 (N for K), 63 (K for H), 67 (E for N), 68 (S for E) and 69 (H for S) from the published sequence. The overall amino acid composition, however, was unchanged because these 5 amino acids were located at different positions compared to the published sequence. As a consequence, the proposed N-glycosylation site was absent, suggesting O-glycosylation of the mature molecule. Recombinant rat C5a with a 6 histidine tag at the N-terminus was expressed in bacteria, purified and renatured. The peptide was as potent as recombinant human C5a in eliciting lysosomal enzyme release from human granulocytes.