TY - JOUR
T1 - Conversion of Ser to Thr residues at the sperm combining-site of mZP3 does not affect sperm receptor activity
AU - Williams, Zev
AU - Litscher, Eveline S.
AU - Wassarman, Paul M.
N1 - Funding Information:
We are very grateful to Luca Jovine and Huayu Qi for advice and discussion throughout the course of this research. Research described here was supported in part by the NIH (HD-35105).
PY - 2003/2/21
Y1 - 2003/2/21
N2 - Mammalian eggs are surrounded by a thick extracellular coat, the zona pellucida, that is composed of three glycoproteins, called ZP1-3. Sperm recognize and bind to O-linked oligosaccharides attached to Ser-332 and Ser-334 at the sperm combining-site of mouse ZP3 (mZP3). Mutation of either of these Ser residues to a small aliphatic amino acid results in the loss of sperm binding to mZP3 in vitro. Here, we converted both Ser-332 and Ser-334 to Thr residues by site-directed mutagenesis. Recombinant mutant glycoprotein made by stably transfected EC cells was purified and then assayed for its ability to inhibit binding of sperm to ovulated eggs in vitro. Results of these experiments suggest that Thr residues can replace the two evolutionarily conserved Ser residues as acceptors for essential O-linked oligosaccharides at the sperm combining-site of mZP3 without affecting the glycoprotein's sperm receptor activity.
AB - Mammalian eggs are surrounded by a thick extracellular coat, the zona pellucida, that is composed of three glycoproteins, called ZP1-3. Sperm recognize and bind to O-linked oligosaccharides attached to Ser-332 and Ser-334 at the sperm combining-site of mouse ZP3 (mZP3). Mutation of either of these Ser residues to a small aliphatic amino acid results in the loss of sperm binding to mZP3 in vitro. Here, we converted both Ser-332 and Ser-334 to Thr residues by site-directed mutagenesis. Recombinant mutant glycoprotein made by stably transfected EC cells was purified and then assayed for its ability to inhibit binding of sperm to ovulated eggs in vitro. Results of these experiments suggest that Thr residues can replace the two evolutionarily conserved Ser residues as acceptors for essential O-linked oligosaccharides at the sperm combining-site of mZP3 without affecting the glycoprotein's sperm receptor activity.
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U2 - 10.1016/S0006-291X(03)00044-5
DO - 10.1016/S0006-291X(03)00044-5
M3 - Article
C2 - 12589785
AN - SCOPUS:0037458978
SN - 0006-291X
VL - 301
SP - 813
EP - 818
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -