Prediction of Sequence-Structure-Function Relationship for Homo sapiens Acrosomal Protein SP-10 Through In-Silico Approaches

Abstract

The acrosomal SP-10 is a testis-specific protein that aids in the interaction between sperm and oocyte. The absence of SP-10 is believed to result in unsuccessful fertilization. The World Health Organization Taskforce on Contraceptive Vaccines declared SP-10 to be a potent primary vaccine candidate to raise an immune-contraceptive to overcome the challenges of current contraceptive methods. In the present work, I attempted to analyze the sequence-structure-function relationship of the Homo sapiens acrosomal protein SP-10 and respective animal homologs by adopting in-silico approaches. The human SP-10 protein was found to a stable protein with a molecular weight of 28 kDa. It is a hydrophilic and acidic protein with a pI of 4.73. The 3D structure of human SP-10 was established for the first time based on template-based modelling as the Protein Data Bank did not have structure for any of its homologs. The phi and psi residues angles of 96.4 % of the obtained structure landed in the most ideal regions of Ramachandran plot implicating a good quality structural model. The SP-10 showed high sequence conservation among all the animal homologs taken for the study. All the homologs of human SP-10 except for the Southern pig-tailed macaque possessed a conserved Ly-6/uPA receptor-like domain and a 12 amino acid pattern within the Ly-6/uPA receptor-like domain. The conserved amino acid pattern along with the whole protein sequence showed an antigenic property that can be used to develop the immuno-contraceptive against SP-10. The template-based model generated for SP-10 in this study can be utilized further for in-silico immunogenic studies in order to generate immune-contraceptive.