Boar spermadhesin PSP-II: location of posttranslational modifications, heterodimer formation with PSP-I glycoforms and effect of dimerization on the ligand-binding capabilities of the subunits.
Spermadhesin PSP-II was isolated from the non-heparin-binding fraction of boar seminal plasma; its disulphide bridge pattern, and the location of a single N-glycosylation site were established. PSP-II forms a heterodimer with specific N-glycoforms of PSP-I. Although both subunits possess heparin-binding capability, the PSP-I/PSP-II complex does not. The heterodimer contains binding sites for zona pellucida glycoproteins and soybean trypsin inhibitor located in the PSP-II subunit. However, the PSP-I/PSP-II heterodimer binds only loosely to the sperm surface and is easily removed during in vitro capacitation, suggesting that the zona pellucida binding activity may not be relevant for gamete interaction. Our results show that dimerization of spermadhesins PSP-I and PSP-II markedly affects their binding capabilities.
Calvete
J J
JJ
Institut für Reproduktionsmedizin, Tierärztliche Hochschule, Hannover, Germany.
Mann
K
K
Schäfer
W
W
Raida
M
M
Sanz
L
L
Töpfer-Petersen
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002241:Carbohydrates / Q000032:analysis; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006023:Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D006031:Glycosylation; D008024:Ligands; D046911:Macromolecular Substances; D008297:Male; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D012661:Semen / Q000378:metabolism*; D029607:Seminal Vesicle Secretory Proteins; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000378:metabolism*; D013552:Swine; D015044:Zona Pellucida / Q000378:metabolism
D002241:Carbohydrates; D006023:Glycoproteins; D008024:Ligands; D046911:Macromolecular Substances; D029607:Seminal Vesicle Secretory Proteins; C074521:seminal vesicle secretory protein II, porcine