Molecular Characterization and In Silico Analyses of Maurolipin Structure as a Secretory Phospholipase A 2 ( sPLA 2 ) from Venom Glands of Iranian Scorpio maurus (Arachnida: Scorpionida)

Abstract

The venom is a mixture of various compounds with specific biological activities, such as the phospholipase $\hspace{0.17em}{A}_2$ ( ${\text{PLA}}_2$ ) enzyme present in scorpion venom. ${\text{PLA}}_2$ plays a key role in inhibiting ryanodine receptor channels and has neurotoxic activity. This study is the first investigation of molecular characterization, cloning, and in silico analyses of ${\text{PLA}}_2$ from Iranian Scorpio maurus, named Maurolipin. After RNA extraction from S. maurus venom glands, cDNA was synthesized and amplified through RT-PCR using specific primers. Amplified Maurolipin was cloned in TA cloning vector, pTG19. For in silico analyses, the characterized gene was analyzed utilizing different software. Maurolipin coding gene with 432 base pair nucleotide length encoded a protein of 144 amino acid residues and 16.34 kilodaltons. Comparing the coding sequence of Maurolipin with other characterized ${\text{PLA}}_2$ from different species of scorpions showed that this protein was a member of the ${\text{PLA}}_2$ superfamily. According to SWISS-MODEL prediction, Maurolipin had 38.83% identity with bee venom ${\text{PLA}}_2$ with 100% confidence and 39% identity with insect phospholipase $A_2$ family, which Phyre2 predicted. According to the three-dimensional structure prediction, Maurolipin with five disulfide bonds has a very high similarity to the structure of ${\text{PLA}}_2$ that belonged to the group III subfamily. The in silico analyses showed that phospholipase $A_2$ coding gene and protein structure is different based on scorpion species and geographical condition in which they live.