Structure and location of the regulatory β subunits in the (αβγδ)4 phosphorylase kinase complex

Abstract

Background: Structural information concerning the phosphorylatable regulatory β subunit of phosphorylase kinase was lacking. Results: Chemical, biochemical, biophysical, and computational approaches revealed secondary, tertiary, and quaternary structures for this subunit. Conclusion: The β subunit is helical and forms the β4-bridged core in the (α βγδ)4 kinase complex. Significance: These findings reveal the architecture of the complex, which provides an explanation for the conformational changes in its bridged core associated with activating β-phosphorylation. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.