Total RNA was extracted from the venom gland of snake
Ophiophagus hannah
. A king cobra venom gland cDNA library was then constructed using purified mRNA from the total RNA. By random sequencing of 200 independent clones, two conserved cDNA sequences of house-keeping genes were obtained. One is ubiquitin fusion protein (GenBank accession number AF297036); the other is ribosomal protein L30 (GenBank accession number AF297033). The former has an open reading frame of 387 bp, encoding a 128 amino acid ubiquitin fusion protein precursor composed of a 76 amino acid ubiquitin domain and followed by a 52 amino acid ribosomal protein L40 domain. The deduced precursor protein from the nucleotide sequence is basic. The C-terminus of the ubiquitin fusion protein contains the zinc-finger motif. The latter has an open reading frame of 348 bp, encoding for 115 amino acid ribosomal protein L30 precursor. The predicted amino acid sequence of ubiquitin fusion protein is highly conserved when compared to the sequences of homologous proteins from sixteen diverse species.
