Oocyte specific oolemmal SAS1B involved in sperm binding through intra-acrosomal SLLP1 during fertilization

► This study identified sperm-egg interaction partners during mammalian fertilization. ► SPR analysis with sperm acrosomal SLLP1 identified the oolemmal partner, SAS1B. ► SAS1B is an oocyte specific metalloprotease. ► The gamete partners revealed high affinity interactions. ► SAS1B deletion in female mice showed 34% reduction in fertility.