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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
Author(s) -
Calvete Juan José,
Mann Karlheinz,
Schäfer Wolfram,
Raida Manfred,
Sanz Libia,
Töpfer-Petersen Edda
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00452-f
Subject(s) - capacitation , chemistry , zona pellucida , protein subunit , acrosin , trypsin , glycoprotein , boar , zona pellucida glycoprotein , biochemistry , biophysics , binding site , in vitro , microbiology and biotechnology , biology , acrosome , sperm , oocyte , enzyme , botany , embryo , gene
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.