E. T. Kaiser

Structure-function analysis of proteins through the design, synthesis, and study of peptide models

Publisher Summary This chapter discusses the structural and functional analysis through the design synthesis and study of peptide models. In order to test the significance of a potential amphiphilic α-helical structure in determining the properties of a biologically active peptide, the chapter had adopted the approach of synthesizing and testing peptide models of the proposed structure. Understanding the functional significance of a potential amphiphilic α helix by this approach is then dependent on the ability of the model peptide to reproduce the properties of the natural peptide, and upon the extent to which the amino acid sequence has been changed. The subsequent demonstration that the properties tested have a definite requirement for the model helix, through the study of “negative” models where features of the helical structure are purposefully absent, is also an essential part of this approach. The biological assays of a synthetic model peptide must be chosen carefully in order to evaluate the function and importance of the incorporated model structure.

Specificity of bovine heart protein kinase for the Δ-stereoisomer of the metal—ATP complex

We have shown, by kinetic and metal-binding studies that the catalytic subunit of bovine heart protein kinase tight& binds 2 divalent cations only in the presence of ~~c~eotjdes such as ATP [ I]_ The data were ~~er~re~ed to indicate that 1 of the 2 divafent cations interacts solely with the enzyme-bound ATP forming the active ternary enzyme-ATP-M” complex. As determined by NMlR, the other, somewhat less tightly-bound divalent cation, bridges the enzyme to the trip~~osph~t~ chain of the metal-ATP complex,. forming a h~~~y-i~ll~bjted