however , several features of the nmr data such as some unusually weak c8/c6 proton to c1 ' proton noe cross-peaks , the presence of relatively intense c2h to c1 ' h noe cross-peaks , and unusual chemical shifts of some 2 '' '' , 2 ' , and 1 ' protons suggest a substantial perturbation of the helix structure at the junctions and along the length of the tract of a residues .
C1521970
features
C1444754
lengt