Before revision:  However , by revisiting the polar clasps, we cannot confirm this very important intersheet hydrogen bond; 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:  However , by revisiting the polar clasps, we found another two hydrogen bonds (B. Asn171 :H-Gln172: OE1 between the strand of one sheet and the opposing strand of the mating sheet ) to replace it .