previously we have shown that the trp-26 side chain is immobile , that the two tyr and three phe side chains undergo only rapid twofold jump motions about their c beta-c gamma bond axis [ gall , c. m. , cross , t. a. , diverdi , j. a. , & opella , s. j . ( 1982 ) proc . natl . acad . sci . u.s.a. 79 , 101-105 ] , and that most of the backbone peptide linkages are highly constrained but do undergo rapid small amplitude motions [ cross , t. a. , & opella , s. j . ( 1982 ) j. mol . biol . 159 , 543-549 ] in the coat protein subunits in the virus particles .
C0004457
axis
C0037949
backbone