15 mer peptides Amino acid length Streptococcus peptides Human peptides Name of human proteins Alleles MSVVTSFYPMYAMTK 14-29 SVVTSFYP SVVTGFFP HAS3 DRB5*01:01, SVVTSFYPMYAMTKE         DRB1*11:01,   DRB1*09:01 VNIAKELGHLDPKHK 136-154 GHLDPKH GHLDAKH Izumo sperm-egg fusion 1 DRB5*01:01 NIAKELGHLDPKHKD           IAKELGHLDPKHKDS           AKELGHLDPKHKDSY           KELGHLDPKHKDSYT           KDSYTKKAKAFKKEA 151-162 KAFKK KAFKK MAPO2 DRB5*01:01 DSYTKKAKAFKKEAE           HKDSYTKKAKAFKKE           KHKDSYTKKAKAFKK           SKTFVTQHTAFSYLA 174-194 SKTFVTQHT SKTFTTQET SA-36 DRB1*04:01,DRB1*08:02, RSKTFVTQHTAFSYL         DRB3*02:02,DRB1*11:01 KVRSKTFVTQHTAFS           VRSKTFVTQHTAFSY           KFKKVRSKTFVTQHT           FKKVRSKTFVTQHTA           Four overlapping peptides obtained from Streptococcal protein, Laminin binding protein represent four different human sperm proteins. The first overlapping peptide with amino acid length spanning between 14 - 29 represents two 15-mer peptides homologous with human sperm protein namely Hyaluronan synthase 3 (HAS3); the second overlapping peptide with amino acid length spanning between 136 - 154 represents five 15-mer peptides homologous with human Izumo sperm - egg fusion 1protein; the third overlapping peptide with amino acid length spanning between 151 - 162 represents four 15-mer peptides homologous with human Motile sperm domain containing protein otherwise named as O6 - methylguanine - induced apoptosis 2 (MAPO2); and the fourth overlapping peptide with amino acid length spanning between 174 - 169 represents six 15-mer peptides homologous with human Sperm antigen 36 (SA - 36). The amino acid sequences obtained from the four Laminin binding protein showing resemblance with the human sperm proteins are SVVTSFYP, GHLDPKH, KAFKK and SKTFVTQHT. All the four overlapping peptides bind to HLA - DRB alleles with high binding affinity.

Table 2: Promiscuous laminin binding peptides interprets functional resemblance with human sperm proteins.