INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Isolation and characterization of a new proteinaceous neurotoxin from snail eggs
Autor/es:
MATÍAS L. GIGLIO; SANTIAGO ITUARTE; HORACIO HERAS
Lugar:
Mar del Plata, Buenos Aires
Reunión:
Congreso; LI Congreso SAIB; 2015
Institución organizadora:
Sociedad Argentina de Investigaciones Bioquímicas
Resumen:
Pomacea is a group of freshwater snails characterized by an unusual reproductive strategy where adult females lay egg masses above the waterline. Aerial oviposition exposes the eggs to several environmental stressors and terrestrialpredators. An adaptation associated with this strategy is the development of a perivitelline fluid (PVF) that includes multifunctional proteins with defensive properties. Among them is the neurotoxin PcPV2 present inPomacea canaliculata eggs. Previous analysis showed that the PVF of related species, P. maculata, is also toxic to mice and contains a putative toxin similar to PcPV2, named PmPV2. The aim of the present work was to isolate and characterize PmPV2. A purification protocol was developed. Structural analyses included electrophoretic and spectroscopic analyses. Structural stability at different pH and temperatures was followed by small angle X-ray diffraction and fluorescence. Functional analysis included toxicity in mice and haemaglutinating capacity. Native PmPV2 is a globular 403-kDa protein, with a Rg= 44 Ȧ and a Dmax= 130 Ȧ. It consists in an octamer of 4 identical 98 kDa heterodimers assembled by non-covalent forces, each composed of 68 and 30 kDa subunits linked bydisulfide bonds. PmPV2 is stable up to 70 °C and between pH 4-10. PmPV2 is a strong neurotoxin (LD50=0.25 mg/kg) with haemaglutinating activity displaying high structural stability.