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Title
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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.
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Authors
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J.J.Calvete,
K.Mann,
W.Schäfer,
M.Raida,
L.Sanz,
E.Töpfer-Petersen.
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Ref.
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Febs Lett, 1995,
365,
179-182.
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PubMed id
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Abstract
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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.
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