Which one of the following sequences functions as a signal for N - linked glycosylation in rough endoplasmic reticulum ?
1
Asn - X - Ser and Asn - X - Thr
2
Asn - X - Ser and Asn - X - Pro
3
Asn - X - Thr and Asn - X - Gly
4
Asn - X - Gly and Asn - X - Pro