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The amino acid sequence of AQN‐3, a carbohydrate‐binding protein isolated from boar sperm Location of disulphide bridges
Author(s) -
Sanz Libia,
Calvete Juan J.,
Mann Karlheinz,
Schäfer Wolfram,
Schmid Erich R.,
Töpfer-Petersen Edda
Publication year - 1991
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(91)81097-r
Subject(s) - gamete , biochemistry , zona pellucida , peptide sequence , carbohydrate , biology , sperm , acrosin , binding protein , chemistry , oocyte , microbiology and biotechnology , acrosome , genetics , gene , embryo
Gamete recognition and adhesion are essential steps in fertilization. Among others, carbohydrate‐binding proteins on the sperm surface have been recognized to play a central role in the initial interaction of the male gamete with components of the zona pellucida of the homologous investing oocyte. We have isolated several members of a carbohydrate‐ and zona pellucida‐binding protein family from ejaculated sperm. Here we report the biological origin and structural characterization of AQN‐3, a component of this carbohydrate‐binding family. The molecular weight of purified AQN‐3 was determined by plasma desorption mass spectrometry. The protein was chemically and enzymatically degraded, the proteolytic fragments isolated and characterized by N‐terminal sequencing and fast atom bombardment mass spectrometry. In this manner we established the complete amino acid sequence of AQN‐3 and the location of its two disulphide bonds. No analogous protein sequence could be found in the MIPS protein sequence data bank, indicating that AQN‐3 may belong to a novel mammalian carbohydrate‐binding protein family.