MOTILITY OF THE N-TERMINAL TAIL OF PHOSPHORYLASE-B AS REVEALED BY CROSSLINKING

There are lysyl-ε-NH2 groups within about 3.5 Å distance across the intersubunit contact area of rabbit muscle phosphorylase b, as shown by cross-linking with malonic diimidate. These include the lysines of N-terminal region as revealed by limited tryptic digestion, but the contribution of the tail lysines to overall formation of covalent dimers is small. The fine structure of dimer band on dodecylsulfate-gelelectrophoretograms of crosslinked phosphorylases suggests that the tail retains its freedom in the phosphorylase b-AMP complex. Amidination induces the dissociation of phosphorylase b dimer, which is slow relative to crosslinking. © 1979.