Electrophysiological Characterization of the Antarease Metalloprotease from Tityus serrulatus Venom
Irene Zornetta,
Michele Scorzeto,
Pablo Victor Mendes Dos Reis,
Maria E. De Lima,
Cesare Montecucco,
Aram Megighian,
Ornella Rossetto
Affiliations
Irene Zornetta
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy
Michele Scorzeto
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy
Pablo Victor Mendes Dos Reis
Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
Maria E. De Lima
Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
Cesare Montecucco
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy
Aram Megighian
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy
Ornella Rossetto
Dipartimento di Scienze Biomediche and Istituto CNR di Neuroscienze, Università di Padova, Via Ugo Bassi 58/B, 35121 Padova, Italy
Scorpions are among the oldest venomous living organisms and the family Buthidae is the largest and most medically relevant one. Scorpion venoms include many toxic peptides, but recently, a metalloprotease from Tityus serrulatus called antarease was reported to be capable of cleaving VAMP2, a protein involved in the neuroparalytic syndromes of tetanus and botulism. We have produced antarease and an inactive metalloprotease mutant in a recombinant form and analyzed their enzymatic activity on recombinant VAMP2 in vitro and on mammalian and insect neuromuscular junction. The purified recombinant antarease paralyzed the neuromuscular junctions of mice and of Drosophila melanogaster whilst the mutant was inactive. We were unable to demonstrate any cleavage of VAMP2 under conditions which leads to VAMP proteolysis by botulinum neurotoxin type B. Antarease caused a reduced release probability, mainly due to defects upstream of the synaptic vesicles fusion process. Paired pulse experiments indicate that antarease might proteolytically inactivate a voltage-gated calcium channel.