3D - STRUCTURE PREDICTION AND STUDY ON T HE INTERACTION BETWEEN RAT CALTRIN AND MODEL MEMBRANES

GRASSO EJ; CORONEL CE; SOTTILE AE

córdoba

Congreso; 52 th Annual Meeting Argentine Society for Biochemistry and Molecular Biology.; 2016

SAIB

Ratcaltrin (calcium transport inhibitor), the small and basicprotein of the seminal plasma, binds to sperm cells during ejaculation andinhibits the extracellular Ca2+ uptake. Thus, it prevents the spermspontaneous acrosomal exocytosis along the female reproductive tract. Althoughthe sequence and some biological features of rat caltrin were studied, its 3Dstructure and physicochemical properties are still unknown. We predicted ratcaltrin 3D structure by molecular homology modeling and threading. Themolecular structure was further characterized by circular dichroism. Surface electrostaticpotentials and electric fields were calculated using the Poisson-Boltzmannequation. Several different bioinformatic tools and available web servers wereused to deeply analyze physicochemical characteristics such as Kyte andDoolittle Hydropathy score and helical wheel projections. Equilibrium spreadingpressure was obtained by Gibbs adsorption isotherms. Interactions between rat caltrinand phospholipids model membranes were defined by penetration (cut off)studies. We observed that rat caltrin is able to penetrate into the membranes, mainlyin negatively charged surfaces and expanded lateral phase states. Resultspresented have significant relevance to further understanding the molecularmechanisms of caltrin to modulate physiological processes associated withfertilization.