Molecular cloning of adenylate kinase from the human filarial parasite Onchocerca volvulus

Adenylate kinases (ADK) are ubiquitous enzymes that contribute to the homeostasis of adenine nucleotides in living cells. In this study, the cloning of a cDNA encoding an adenylate kinase from the filaria Onchocerca volvulus has been described. Using PCR technique, a 281 bp cDNA fragment encoding part of an adenylate kinase was isolated from an O. volvulus cDNA library. Use of this fragment as a probe allowed the isolation of a larger cDNA clone through the searching the GenBank expressed sequence tag database. The full-length cDNA encodes 236 amino acid residues with a predicted molecular mass of 26.177 kDa. The deduced amino acid sequence exhibited 80% identity to the homologous adenylate kinase identified from Caenorhabditis elegans. Domain analysis of the resulting protein sequence was found to contain "adenylate kinase signature" motif which is highly conserved in all known ADKs. Multiple alignments showed that the N-terminal is well conserved, whereas the C-terminal is the most variable region.