title: HSP-1/2, a major protein of equine seminal plasma, exhibits chaperone-like activity.
abstract: The major bovine seminal plasma protein, PDC-109 exhibits chaperone-like activity (CLA) against a variety of target proteins. The present studies show that the homologous protein from equine seminal plasma, HSP-1/2 also exhibits CLA and inhibits the thermal aggregation of target proteins such as lactate dehydrogenase, and DTT-induced aggregation of insulin in a concentration-dependent manner. Phosphorylcholine binding inhibited the CLA of HSP-1/2, suggesting that aggregation state of the protein is important for this activity. These results demonstrate that HSP-1/2 functions as a molecular chaperone in vitro, and suggest that it may protect other proteins of equine seminal plasma from unfolding/misfolding or aggregation. These results suggest that homologous proteins from the seminal plasma of other mammals also exhibit CLA, which will be physiologically relevant.
authors.affiliation: School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
authors.forename: Rajeshwer Singh
authors.initials: RS
authors.lastname: Sankhala
authors.forename: C Sudheer
authors.initials: CS
authors.lastname: Kumar
authors.forename: Bhanu Pratap
authors.initials: BP
authors.lastname: Singh
authors.forename: A
authors.initials: A
authors.lastname: Arangasamy
authors.forename: Musti J
authors.initials: MJ
authors.lastname: Swamy
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D004229:Dithiothreitol / Q000737:chemistry / Q000494:pharmacology; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D006736:Horses / Q000378:metabolism*; D008297:Male; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D010767:Phosphorylcholine / Q000494:pharmacology; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012661:Semen / Q000378:metabolism*; D029589:Seminal Plasma Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; C095321:HSP-1 protein, Equus caballus; C106240:HSP-2 protein, Equus caballus; D018832:Molecular Chaperones; D029589:Seminal Plasma Proteins; D010767:Phosphorylcholine; D005954:Glucosephosphate Dehydrogenase; D004229:Dithiothreitol