Expression and bioinformatic analysis of snake venom metalloproteinase (svmp) from <i>Naja nigricollis</i> snake venom gland

Abstract

Elapid snake venom is highly valuable and also a source of medically important peptides. The venom of Naja nigricollis is unique among elapids in that it contains mainly cytotoxins, but also with other components. Naja nigricollis metalloproteinase was partially purified by two step purification process. Gel filtration on Sephadex G-75 column (yield 32.0) and gradient ion exchange chromatography on  diethylaminoethyl (DEAE) cellulose column (yield 18.10) to apparent homogeneity. The protease activity was studied according to modified Kunitz method and the enzyme was found to be active at optimum pH and temperature of 7.0 and 40°C respectively. The effect of the enzyme on casein was found to be highest at 1.5% concentration. The kinetic parameters, Km and Vmax were found to be 0.27787 mg/ml and 2.3175µmol/min respectively. The enzyme was stable at pH 7.0 ̶ 9.0 and at a temperature range of 30 ̶ 60°C. The snake venom metalloproteinase cDNA from N. nigricollis venom gland was sequenced and was found to contain 132 nucleotides sequence which codes a polypeptide of 44 amino acids with estimated molecular mass of 50 KD. The deduced novel amino acid sequence had a similarity with Najaatra metalloproteinase atrase B (91%), N. atra K-like metalloproteinase precursor (91%) and N. atra atragin precursor (83%). The sequenced cDNA was found to have the disintegrin-like domain of the metalloproteinase enzyme of Naja nigricollis snake specie.

Keyword: Elapid, Naja nigricollis. Metalloproteinase