Aim： To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the process of prostate specific antigen （PSA） digesting semenogelin （Sg）. Methods： Human Sg cDNA （nucleotides 82-849...Aim： To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the process of prostate specific antigen （PSA） digesting semenogelin （Sg）. Methods： Human Sg cDNA （nucleotides 82-849） and Eppin cDNA （nucleotides 70-423） were generated by polymerase chain reaction （PCR） and cloned into pET-100D/TOPO. Recombinant Eppin and Sg （rEppin and rSg） were produced by BL21 （DE3）. The association of Eppin with Sg was studied by far-western immunoblot and radioautography. In vitro the digestion of rSg by PSA in the presence or absence of rEppin was studied. The effect of anti-Q20E （N-terminal） and C-terminal of Eppin on Eppin-Sg binding was monitored. Results： Eppin binds Sg on the surface of human spermatozoa with the C-terminal of Eppin （amino acids 75-133）. rSg was digested with PSA and many low molecular weight fragments were produced. When rEppin is bound to rSg, then digested by PSA, incomplete digestion and a 15-kDa fragment results. Antibody binding to the N-terminal of rEppin did not affect rSg digestion. Addition of antibodies to the C-terminal of rEppin inhibited the modulating effect of rEppin. Conclusion： Eppin protects a 15-kDa fragment of rSg from hydrolysis by PSA.展开更多
To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the liquafication of semen. Methods： Human semenogelin cDNA （nucleotides 82-849） and Eppin cDNA （nucleotides 70-423） were gen...To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the liquafication of semen. Methods： Human semenogelin cDNA （nucleotides 82-849） and Eppin cDNA （nucleotides 70-423） were generated by PCR and cloned into pET-100D/TOPO.Recombinant Eppin and Sg were produced by BL21 （DE3）. The association of Eppin with Sg was studied by far-western and radioautography.In vitro the digestion of Sg by PSA in the presence or absence of recombinant Eppin was studied. The effect of anti-Q20E （N-terminal） and C-terminal of Eppin on Eppin-Sg binding was monitored. Results： Eppin binds Sg on the surface of human spermatozoa with C-terminal Eppin （aa75-133）.Recombinant Sg was digested with PSA ,many low molecular weight fragments were produced, when Eppin is bound to Sg ,then digested by PSA ,producing incomplete digestion and a 14.5-14.8 kDa fragmen. Antibody binding to the N-terminal of Eppin did not affect Sg digestion. Addition of antibodies to the C-terminal of Eppin inhibited the modulating effects of Eppin. Conclusion： Eppin modulates the digestion activity of PSA through binding Sg.The active site locates at C-terminal.展开更多
During liquefaction of the ejaculate, the semen coagulum proteins semenogelin I （SEMG1） and semenogelin Ⅱ （SEMG2） are degraded to low molecular mass fragments by kallikrein-related peptidase 3 （KLK3）, also know...During liquefaction of the ejaculate, the semen coagulum proteins semenogelin I （SEMG1） and semenogelin Ⅱ （SEMG2） are degraded to low molecular mass fragments by kallikrein-related peptidase 3 （KLK3）, also known as prostate-specific antigen. Semenogelin molecules initiate their own destruction by chelating Zn^2＋ that normally would completely inhibit the proteolytic activity of KLK3. In a similar way, semenogelins might regulate the activity of kallikrein-related peptidases in the epididymis, something that might be of importance for the maturation of spermatozoa or generation of anti-bacterial peptides. Studies on the evolution of semen coagulum proteins have revealed that most of them carry an exon that displays a rapid and unusual evolution. As a consequence, homologous proteins in rodents and primates show almost no conservation in primary structure. Further studies on their evolution suggest that the progenitor of the semen coagulum proteins probably was a protease inhibitor that might have displayed antimicrobial activity. The semenogelin locus on chromosome 20 contains at least 17 homologous genes encoding probable protease inhibitors with homology to semen coagulum proteins. All of these are highly expressed in the epididymis where they, similar to the semenogelins, could affect the maturation of spermatozoa or display antibacterial properties. （Asian J Androl 2007 July; 9： 540-544）展开更多
文摘Aim： To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the process of prostate specific antigen （PSA） digesting semenogelin （Sg）. Methods： Human Sg cDNA （nucleotides 82-849） and Eppin cDNA （nucleotides 70-423） were generated by polymerase chain reaction （PCR） and cloned into pET-100D/TOPO. Recombinant Eppin and Sg （rEppin and rSg） were produced by BL21 （DE3）. The association of Eppin with Sg was studied by far-western immunoblot and radioautography. In vitro the digestion of rSg by PSA in the presence or absence of rEppin was studied. The effect of anti-Q20E （N-terminal） and C-terminal of Eppin on Eppin-Sg binding was monitored. Results： Eppin binds Sg on the surface of human spermatozoa with the C-terminal of Eppin （amino acids 75-133）. rSg was digested with PSA and many low molecular weight fragments were produced. When rEppin is bound to rSg, then digested by PSA, incomplete digestion and a 15-kDa fragment results. Antibody binding to the N-terminal of rEppin did not affect rSg digestion. Addition of antibodies to the C-terminal of rEppin inhibited the modulating effect of rEppin. Conclusion： Eppin protects a 15-kDa fragment of rSg from hydrolysis by PSA.
文摘To study the molecular mechanism of epididymal protease inhibitor （Eppin） modulating the liquafication of semen. Methods： Human semenogelin cDNA （nucleotides 82-849） and Eppin cDNA （nucleotides 70-423） were generated by PCR and cloned into pET-100D/TOPO.Recombinant Eppin and Sg were produced by BL21 （DE3）. The association of Eppin with Sg was studied by far-western and radioautography.In vitro the digestion of Sg by PSA in the presence or absence of recombinant Eppin was studied. The effect of anti-Q20E （N-terminal） and C-terminal of Eppin on Eppin-Sg binding was monitored. Results： Eppin binds Sg on the surface of human spermatozoa with C-terminal Eppin （aa75-133）.Recombinant Sg was digested with PSA ,many low molecular weight fragments were produced, when Eppin is bound to Sg ,then digested by PSA ,producing incomplete digestion and a 14.5-14.8 kDa fragmen. Antibody binding to the N-terminal of Eppin did not affect Sg digestion. Addition of antibodies to the C-terminal of Eppin inhibited the modulating effects of Eppin. Conclusion： Eppin modulates the digestion activity of PSA through binding Sg.The active site locates at C-terminal.
文摘During liquefaction of the ejaculate, the semen coagulum proteins semenogelin I （SEMG1） and semenogelin Ⅱ （SEMG2） are degraded to low molecular mass fragments by kallikrein-related peptidase 3 （KLK3）, also known as prostate-specific antigen. Semenogelin molecules initiate their own destruction by chelating Zn^2＋ that normally would completely inhibit the proteolytic activity of KLK3. In a similar way, semenogelins might regulate the activity of kallikrein-related peptidases in the epididymis, something that might be of importance for the maturation of spermatozoa or generation of anti-bacterial peptides. Studies on the evolution of semen coagulum proteins have revealed that most of them carry an exon that displays a rapid and unusual evolution. As a consequence, homologous proteins in rodents and primates show almost no conservation in primary structure. Further studies on their evolution suggest that the progenitor of the semen coagulum proteins probably was a protease inhibitor that might have displayed antimicrobial activity. The semenogelin locus on chromosome 20 contains at least 17 homologous genes encoding probable protease inhibitors with homology to semen coagulum proteins. All of these are highly expressed in the epididymis where they, similar to the semenogelins, could affect the maturation of spermatozoa or display antibacterial properties. （Asian J Androl 2007 July; 9： 540-544）
