title: Kinetic and structural studies on the interactions of heparin and proteins of human seminal plasma using surface plasmon resonance.
abstract: Heparin is naturally occurring polysaccharides which interacts with seminal plasma proteins and regulate multiple steps in fertilization process. Qualitative and quantitative information regarding the affinity for heparin-seminal plasma proteins interactions is not generally well documented and there are no reports of a comprehensive analysis of these interactions in human seminal plasma. Such information should improve our understanding of how GAGs especially heparin present in the reproductive tract regulate fertilization. In this study, we use SPR to study interactions of heparin with various seminal plasma heparin-binding proteins (HBPs). HBPs like lactoferrin (LF), fibronectin fragment (FNIII), semenogelinI (SGI) and prostate specific antigen (PSA) all bind heparin with different binding kinetics and affinities. Kinetic data suggests that FNIII binds heparin with a high affinity (KD=3.2 nM), while PSA binds heparin with a micromolar affinity (KD=11.1 μM). Preincubation of SGI with heparin inhibits the binding of SGI to immobilized PSA in a dose-dependent manner, while FNIII incubated with heparin binds with an increased affinity to PSA. Solution-competition studies show that the minimum size of a heparin oligosaccharide capable of binding with PSA is greater than a tetrasaccharide, with LF and SGI is larger than a hexasaccharide and for FNIII is larger than an octasaccharide.
authors: Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India.
authors: Vijay
authors: V
authors: Kumar
authors: Vikash Kumar
authors: VK
authors: Yadav
authors: Md Imtaiyaz
authors: MI
authors: Hassan
authors: Abhay Kumar
authors: AK
authors: Singh
authors: Sharmistha
authors: S
authors: Dey
authors: Sarman
authors: S
authors: Singh
authors: Tej P
authors: TP
authors: Singh
authors: Savita
authors: S
authors: Yadav
mesh_terms: D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism; D006493:Heparin / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D007781:Lactoferrin / Q000737:chemistry / Q000378:metabolism; D008297:Male; D017430:Prostate-Specific Antigen / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D029589:Seminal Plasma Proteins / Q000737:chemistry / Q000378:metabolism; D029607:Seminal Vesicle Secretory Proteins / Q000737:chemistry / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D005353:Fibronectins; D029589:Seminal Plasma Proteins; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D006493:Heparin; D007781:Lactoferrin; D017430:Prostate-Specific Antigen