title: A male-specific (cysteine-rich) protein of Oesophagostomum dentatum (Strongylida) with structural characteristics of a serine protease inhibitor containing two trypsin inhibitor-like domains.
abstract: A cDNA was isolated from an adult male Oesophagostomum dentatum gene library by screening with a male-specific, partial expressed sequence tag (EST) probe identified previously using a differential display technique. The full-length cDNA of 642 bp included 5' and 3' untranslated regions of 44 and 121 nucleotides, respectively, and encoded a predicted protein with a putative 18 amino acid signal sequence and a mature polypeptide of 14.7 kDa comprising approximately 15% cysteine residues. The amino acid sequence showed similarity with a number of proteins from Caenorhabditis elegans, parasitic nematodes, insects and amphibia, all of which contain a trypsin inhibitor-like cysteine-rich domain. A 3-dimensional structure model constructed for the O. dentatum protein (designated OdmCRP) inferred that it is composed of 2 domains, each with 5 disulfide bonds, which are indicative of the Ascaris family of serine protease inhibitors. These findings indicate that OdmCRP, with 2 structural domains relating to functionally active sites, is a new member of this inhibitor family.
authors.affiliation: Victorian Institute of Animal Science, Attwood, Australia.
authors.forename: P R
authors.initials: PR
authors.lastname: Boag
authors.forename: S
authors.initials: S
authors.lastname: Ranganathan
authors.forename: S E
authors.initials: SE
authors.lastname: Newton
authors.forename: R B
authors.initials: RB
authors.lastname: Gasser
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D003001:Cloning, Molecular; D003545:Cysteine / Q000032:analysis*; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D015870:Gene Expression; D015723:Gene Library; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000737:chemistry* / Q000235:genetics*; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009815:Oesophagostomum / Q000737:chemistry* / Q000235:genetics*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D012727:Sex Characteristics; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D014361:Trypsin Inhibitors; D003545:Cysteine