title: Molecular heterogeneity of gelatin-binding proteins from human seminal plasma.
abstract: Defining the molecular characteristics of seminal plasma proteins is essential for understanding their function in physiological and pathological conditions. Starting from the predicted importance of human seminal plasma gelatin-binding proteins, comprising fibronectin (FN) and FN-related molecules, for male fertility, this study aims at gaining insight into their immuno-glycobiochemical properties. Human seminal plasma from subjects with normal semen parameters were separated on a gelatin-Sepharose column and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using antibodies against distinct FN forms. Heterogeneity of the isolated molecular species was examined by protein chip arrays combined with surface-enhanced laser desorption/ionization time of flight mass spectrometry, on normal, metal and hydrophobic surfaces. Carbohydrate composition was investigated using mannose-, fucose- and sialic acid-specific plant lectins and galectin-1. The results obtained indicated a pattern of isolated proteins corresponding to that of known FN fragments, as confirmed by immunoreactivity. Among them heparin-binding ability was preferentially associated with low molecular mass species. As for posttranslational modifications, phosphorylation and glycosylation of distinct fragments were revealed. Lectin binding to fragments containing the gelatin-binding domain, particularly with Ricinus communis agglutinin I, was stronger than to fragments containing the cell-binding site of FN. A low level of sialylation and distinctive concanavalin A- and Lens culinaris agglutinin-reactive species were also observed. Galectin-1 did not interact with the isolated preparation. Resolving the molecular heterogeneity of normal human seminal plasma FN and gaining initial insight into possible similarities/differences with known FN molecular species may be considered a prerequisite step preceding challenging the clinical usefulness of these molecular properties.
authors.affiliation: Department for Immunochemistry and Glycobiology, Institute for the Application of Nuclear Energy-INEP, University of Belgrade, Banatska 31b, Zemun-Belgrade 11080, Serbia. miraj@inep.co.rs
authors.forename: Maja M
authors.initials: MM
authors.lastname: Kosanović
authors.forename: Miroslava M
authors.initials: MM
authors.lastname: Janković
mesh_terms: D002847:Chromatography, Agarose; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000032:analysis / Q000378:metabolism*; D037483:Galectin 1 / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D006493:Heparin / Q000378:metabolism; D006801:Humans; D008297:Male; D010766:Phosphorylation; D037121:Plant Lectins / Q000737:chemistry / Q000378:metabolism; D040081:Protein Array Analysis; D011485:Protein Binding; D012661:Semen / Q000737:chemistry / Q000378:metabolism*; D029589:Seminal Plasma Proteins / Q000032:analysis / Q000378:metabolism*
chemical_list: D005353:Fibronectins; D037483:Galectin 1; C445499:LGALS1 protein, human; D037121:Plant Lectins; D029589:Seminal Plasma Proteins; D006493:Heparin