Pernin: a novel, self-aggregating haemolymph protein from the New Zealand green-lipped mussel, Perna canaliculus (Bivalvia: Mytilidae).
Comp Biochem Physiol B Biochem Mol Biol
; 128(4): 767-79, 2001 Apr.
Article
in En
| MEDLINE
| ID: mdl-11290459
ABSTRACT
A protein, designated pernin, found in the New Zealand green-lipped mussel, comprises almost all of the protein in cell-free haemolymph. It occurs as large, aggregate structures of several hundred units resembling small virus-like particles. Pernin is a non-pigmented, glycosylated protein, composed of 497 amino acids, which has an estimated molecular mass of 60 kDa. It is exceptionally rich in histidine (13.7%) and aspartic acid (12.3%), amino acids both known to participate in the binding of divalent metal cations. In addition, pernin has serine protease inhibitor activity, likely due to a sequence of eight N-terminal amino acid residues, separated from the remainder of the protein via a histidine-aspartate spacer. The pernin monomer comprises three regions of obvious sequence duplication. These make up approximately 95% of the pernin molecule and have sequences clearly homologous to the active-site domain of Cu-Zn SODs (superoxide dismutases). Despite several of the metal ion co-ordinating histidine residues being retained, pernin contains no Cu or Zn. It is, however, associated with Fe with an apparent stoichiometry of 1 atom of Fe to 6 molecules of pernin. Since pernin has no demonstrable SOD activity, these SOD-derived sequences presumably have been modified for another function.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Blood Proteins
/
Glycoproteins
/
Hemolymph
/
Bivalvia
/
Anticoagulants
Limits:
Animals
Country/Region as subject:
Oceania
Language:
En
Journal:
Comp Biochem Physiol B Biochem Mol Biol
Journal subject:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Year:
2001
Document type:
Article
Affiliation country:
Nueva Zelanda