Contents

13 September 1996
Vol 273, Issue 5281

About The Cover

Subunit contact region (subunits are purple and turquoise) of the unphosphorylated, inactive yeast enzyme glycogen phosphorylase, shown with bound inhibitor glucose-6-phosphate (atom cluster at middle left, phosphate colored light green). After phosphorylation of a threonine residue (atom cluster at bottom right), the amino-terminal segment (red ribbon) refolds and then interferes with inhibitor binding and activates the enzyme. See page 1539. [Image: Kai Lin and Peter K. Hwang]