sentence: The radiolabeled Snf2 was cleaved under limiting conditions at Asn-Gly ( hydroxylamine ) , Met ( cyanogen bromide ) or Cys ( NTCB or 2-nitro-5-thiocyanobenzoic acid ) residues , resolved by SDS – PAGE and visualized by phosphorimaging to determine the location of the crosslinked site ( Information of Supplementary Data ) .