Before revision:  instead we found another hydrogen bond ( Asn171 :H-Gln172: OE1  between the strand  of one sheet and the opposing strand  of the mating sheet ) to replace it .
After revision:  instead we found another hydrogen bond ( Asn171 :H-Gln172: OE1 between the strand A of one sheet and the opposing strand of the mating sheet ) to replace it .