Mineralogy: An Introduction to the Study of Minerals and Crystals. E. H. Kraus , W. F. Hunt , L. S. Ramsdell

Thermodynamic Study of the Binding of the Tandem-SH2 Domain of the Syk Kinase to a Dually Phosphorylated ITAM Peptide: Evidence for Two Conformers

“…Calorimetric measurements give a direct evaluation of the binding enthalpy (∆H°) which, when studied as a function of temperature to extract the heat capacity change (∆C p o ), helps to discern whether binding occurs via a rigid-body or an induced-fit mechanism (33). Moreover, the temperature dependence of the ∆C p o , which is most precisely assessed by calorimetry rather than by van't Hoff analysis, can determine if binding is linked to a preexisting conformational equilibrium (34,35). A detailed understanding of the energetics of tyrosine-phosphorylated peptide recognition by SH2 domains would greatly facilitate drug design efforts; SH2 domains have been the targets of intensive pharmacological research (36), and recently, a specific inhibitor of the interaction of Syk with the Fc receptor I, apparently involving the SH2 domains, has been reported (37).…”

Isoergonic Cooperativity in Glutamate Dehydrogenase Complexes: A New Form of Allostery

“…The only variable parameters in the system are the equilibrium constants of the X ⇌ O isomerization step, which may have the values K 01 or K 02 , respectively, depending only on the number of open states on the other subunits. It should be noted that in our assumed model this value is unaffected by the binding of L. The dependence of q on L T for the two subunit case is where the parameters are defined as in eq 4.…”

A Close-Packed Planar 4-Atom Motif Serves as a Variable-Pathway Mechanistic Switching Device in Enzymatic Catalysis

“…Each of the four atoms have been explicitly implicated in 4 X-ray crystal structures of both open and closed forms of a bacterial glutamate dehydrogenase have been obtained (11). Calorimetric studies from this laboratory have demonstrated two-state behavior for a number of different complexes of a variety of pyridine nucleotide-linked dehydrogenases (16). The behavior of the set of 38 such complexes could be accounted for by a two-state ligand binding process involving a constant intrinsic ⌬HЊ of ϩ22 Kcal.…”