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 ∼ 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-dimensio..