Mechanism of activation of a cyclic adenosine 3':5'-monophosphate phosphodiesterase from bovine heart by calcium ions. Identification of the protein activator as a Ca2+ binding protein.

The regulation of skeletal muscle phosphorylase kinase by Ca2

Publisher Summary This chapter describes the fundamental aspects of gel chromatography as they comprise a set of analytical techniques that a protein chemist may use. The unifying principles that underlie these techniques have been a major focus of interest. The chapter focuses on the two fundamental principles that underlie the use of gel chromatographic systems as analytical tools in protein chemistry: (1) partition coefficients depend on molecular size and shape in contrast to surface or charge properties. (2) Gel columns are linear chromatographic systems and can, therefore, be used for the analysis of nonlinear molecular phenomena such as those occurring in chemically reacting multicomponent systems. Although deviations from these two principles of ideal behavior are almost always present, their magnitude is almost always small. In addition, it is evident on both theoretical and experimental grounds that the group of techniques based on the partitioning of molecules into porous gel networks constitutes an extremely versatile and useful array of analytical tools for the studies of protein systems. It may be expected, therefore, that the application of these techniques will be extended to a much wider group of experimental systems.

Analytical gel chromatography of proteins.

Subunit interactions and their relationship to the allosteric properties of rabbit skeletal muscle phosphorylase b.

Protein-drug binding is, in essence, an interaction between a biological macromolecule and a small molecule. This type of complexation is only one of many different types of protein interaction, all of which are molecularly intertwined in a cellular or organ environment. In a general perspective, it is convenient to view such interactions as falling into two broad categories (FIGURE 1 ) , intramolecular and intermolecular. Intramolecular interactions are manifested in the different conformations that may coexist for a particular species of protein. Intermolecular complexes may be further subdivided into two classes (FIGURE 1 ), those with small molecules and those with other macromolecules. Included among the latter are the quaternary structures constituted of identical subunits, in addition to heteromeric ensembles of various types, for example, protein-protein, protein-nucleic acid. These interactions are the foundation of an interlocked set of macromolecular dynamic rearrangements that provide the fine modulation within and between parts of an organism. Small-molecule binding plays a crucial role in this manifold because it usually provides the molecular coupling device for interlinking the macromolecular states and for adjusting their relative concentrations. A general overview of protein-small-molecule binding should cover the following aspects of such interactions: 1. stoichiometry; 2. energetics; 3. molecular nature; 4. dynamics; and 5 . biological function. This brief review will describe a few representative studies from these topics to illustrate some of the general principles that govern macromolecule-minimolecule interactions.

Gordon F. Fairclough

Papers

Peptide-protein interaction as studied by gel filtration.

Subunit structure of dipeptidyl transferase.

Arsanilazochymotrypsinogen. Extrinsic cotton effects of an arsanilazotyrosyl chromophore as a conformation probe of zymogen activation