OBJECTIVE: To characterize the major membrane protein of goat spermatozoa. DESIGN: Basic research. SETTING: Samples collected from local slaughterhouse and study conducted in an academic research environment. PATIENT(S): Goat epididymal tissue. INTERVENTION(S): Goat epididymal tissues were collected immediately after slaughter and the spermatozoa were isolated within 2 hours. Sperm immobilization test was performed with motile spermatozoa at 32 degrees C within 3-4 hours of collection and isolation of the cells. MAIN OUTCOME MEASURE(S): The heparin-binding sperm membrane protein (HBSM) of goat is insensitive to trypsin and its antisera immobilize spermatozoa in presence of complement. RESULT(S): Forty-two percent of membrane protein could be extracted with 0.25% (wt/vol) 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) from the isolated sperm membrane. By heparin-affinity chromatography, 46% of the extracted protein was recovered. Positive hybridization with radiolabeled heparin on western transfer confirmed the heparin-binding property of the protein (HBSM). Heparin binding to HBSM is an ionic bondage and can be disrupted by 1 M NaCl, as revealed by 86% recovery of the radiolabeled heparin in trichloroacetic acid-precipitated supernatant of [(125)I] heparin-HBSM conjugate. Heparin-binding sperm membrane protein is localized at the anterior region of the spermatozoal head. No detectable proteolytic fragment of HBSM was detected after limited digestion by trypsin. Heparin-binding sperm membrane protein antisera (1:10,000 titer) developed from rabbit did not recognize the denatured protein. The antisera inhibited spermatozoal motility in a complement-dependent manner. CONCLUSION(S): We suggest that the heparin-binding motif of the spermatozoal membrane protein might be required in modulation of the spermatozoal motility.
OBJECTIVE: To characterize the major membrane protein of goat spermatozoa. DESIGN: Basic research. SETTING: Samples collected from local slaughterhouse and study conducted in an academic research environment. PATIENT(S): Goat epididymal tissue. INTERVENTION(S): Goat epididymal tissues were collected immediately after slaughter and the spermatozoa were isolated within 2 hours. Sperm immobilization test was performed with motile spermatozoa at 32 degrees C within 3-4 hours of collection and isolation of the cells. MAIN OUTCOME MEASURE(S): The heparin-binding sperm membrane protein (HBSM) of goat is insensitive to trypsin and its antisera immobilize spermatozoa in presence of complement. RESULT(S): Forty-two percent of membrane protein could be extracted with 0.25% (wt/vol) 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) from the isolated sperm membrane. By heparin-affinity chromatography, 46% of the extracted protein was recovered. Positive hybridization with radiolabeled heparin on western transfer confirmed the heparin-binding property of the protein (HBSM). Heparin binding to HBSM is an ionic bondage and can be disrupted by 1 M NaCl, as revealed by 86% recovery of the radiolabeled heparin in trichloroacetic acid-precipitated supernatant of [(125)I] heparin-HBSM conjugate. Heparin-binding sperm membrane protein is localized at the anterior region of the spermatozoal head. No detectable proteolytic fragment of HBSM was detected after limited digestion by trypsin. Heparin-binding sperm membrane protein antisera (1:10,000 titer) developed from rabbit did not recognize the denatured protein. The antisera inhibited spermatozoal motility in a complement-dependent manner. CONCLUSION(S): We suggest that the heparin-binding motif of the spermatozoal membrane protein might be required in modulation of the spermatozoal motility.