Primary structure of the precursor for the anthozoan neuropeptide Antho-RFamide from Renilla köllikeri: Evidence for unusual processing enzymes
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Neuropeptides containing the C-terminal sequence Arg-Phe-NH2 are an important group of hormones mediating or modulating neuronal communication. Arg-Phe-NH2 peptides are abundant in evolutionarily "old" nervous systems such as those of coelenterates, the lowest animal group having a nervous system. Here, we have cloned the precursor protein for the anthozoan neuropeptide Antho-RFamide (<Glu-Gly-Arg-Phe-NH2) from the sea pansy Renilla köllikeri. This precursor contains 36 copies of immature Antho-RFamide (Gln-Gly-Arg-Phe-Gly) and two additional putative neuropeptide sequences, which are regularly distributed over the precursor protein. Of the 36 Antho-RFamide sequences, 29 copies are separated by the five amino acid spacer sequence Arg-Glu/Gly-Asn/Ser/Asp-Glu/Lys-Glu. This implicates processing at single Arg and single Glu residues. Endoproteolytic cleavage at the C-terminal side of paired or single basic residues is a well known initial step in the maturation of precursor proteins. Cleavage at the C-terminal side of acidic residues, however, is unusual and must be catalyzed by a new type of processing enzyme. This processing enzyme is most likely to be an endoprotease, because the simplest way to generate Antho-RFamide is by endoproteolytic cleavage at the C-terminal side of Glu residues. The enzyme could also be an aminopeptidase, but in this case other proteases must be involved. As a possible alternative, one single "unspecific" aminopeptidase could cleave at Glu, Asp, Gly, Asn, Ser, and possibly also at other residues, and thus liberate all Antho-RFamide sequences. The processing of one precursor molecule probably yields 38 neuropeptides.(ABSTRACT TRUNCATED AT 250 WORDS)
Originalsprog | Engelsk |
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Tidsskrift | Journal of Neurochemistry |
Vol/bind | 62 |
Udgave nummer | 3 |
Sider (fra-til) | 1214-22 |
Antal sider | 9 |
ISSN | 0022-3042 |
Status | Udgivet - 1 mar. 1994 |
ID: 265215