Construction of a structural model of bovine caltrin protein interacting with artifitial membranes

CORONEL, CARLOS E.; GRASSO, ERNESTO J.

Congreso; XLVII Reunión Anual de la SAB; 2018

Bovine caltrin (calcium transport inhibitor) is a small and basic protein of the seminal plasma which binds to epididymal spermatozoa during ejaculation, and inhibits the sperm extracellular Ca2+ uptake. This inhibitory activity seems to play an important regulatory function, preventing the premature acrosomal exocytosis and the hyperactivated motility during the sperm journey along the female reproductive tract. The binding of bovine caltrin to specific regions of the spermatozoa, where Ca2+ influx may take place ti trigger these two Ca-dependent physiological processes suggests the existence of receptor molecules or precise protein-phospholipids arrangements in the sperm membrane. At present, the molecular mechanisms of recognition and interaction between caltrin and sperm membranes have not been elucilated. In this work we have built a theoretical model of the interaction between bovine caltrin and model membranes by using several bioinformatics tools. A hydrophobic 13-residues (PKLLETFLSKWIG) peptide with favorable thermodynamic properties to penetrate into biological membranes was identified in the protein primary structure. It may be responsible of caltrin-sperm binding to modulate the intracellular signaling of these tw Ca-dependent physiological events.