Microcalorimetric Studies of the Interactions of Imidazole with Immobilized Cu(II): Effects of pH Value and Salt Concentration

Abstract

ions frequently varies with the topography of the protein In this investigation, we measured the influence of pH value surface and the chemistry and physical conditions of the and salt concentration on the heat of interaction between imidazole interaction conditions. Although mechanisms have been proand CS-IDA-Cu(II) gel with a highly sensitive microcalori-posed for IMA with protein, the macromolecular recognition meter. The direct enthalpy measurement of the interaction pro-of protein by immobilized ions remains unclear. In the pro- tein surface, the pH value of the interaction, the salt type Key Words: immobilized metal ion affinity; microcalorimetry; and concentration (16,17), the temperature (15, 16), the adsorption; imidazole; IMA.protein structure, the surface chemistry, and the degree of hydration of the protein.Previous literatures have established those factors' contri-

Staphylococcus aureus -Fibronectin Interactions with and without Fibronectin-Binding Proteins and Their Role in Adhesion and Desorption

“…The calorimeter was placed in a temperature-controlled environment (20 Ϯ 0.1°C), which allowed baseline stability of Ϯ0.1 W over a 24-h period (17). The instrument had electrical calibration with precision better than 1%, and proper calibration was regularly checked by measuring the dilution enthalpy of concentrated sucrose solutions (26). Experiments were performed isothermally at 25°C in 4-ml stainless steel ampoules.…”

Thermodynamic analysis of the interaction between proteins and solid surfaces: application to liquid chromatography

“…For this reason, progress in this field of protein-or polypeptide-ligand interactions from the perspectives of the interaction thermodynamics and extrathermodynamics has somewhat been constrained despite its obvious pervasiveness across all areas of the biosciences and bio-technology. Important contributions have, however, been made by various investigators, including Horvath et al, 23,24,28,32,38,66 Andrade et al, 67,68 Hearn et al, [33][34][35][69][70][71] (unpublished observations) Norde et al, [19][20][21]72,73 Chen et al, 11,12,[59][60][61][62][63]74 Lenoff et al 75,76 and Stahlberg et al, 77,78 who have systematically investigated from thermodynamic or biophysical perspectives the energetics and mechanisms of the protein or polypeptide binding processes in liquid chromatography as well as in the more general scenarios of protein-or polypeptide-ligand docking to chemically modified surfaces. Several examples of these approaches to elucidate the interaction thermodynamics of proteins and polypeptides with ligands in the free or immobilised states are subsequently presented in this article.…”

Microcalorimetric Study of the Effect of Hexa-histidine Tag and Denaturant on the Interaction Mechanism between Protein and Metal-Chelating Gel

“…To discuss the interaction mechanisms in detail, particularly in the study of the interaction mechanism between the protein and the immobilized metal ions, an adsorption process for containing five sequential subprocesses as have been mentioned in our previous studies in IMAC (19)(20)(21)(22) was proposed: (a) water, small molecules, such as urea in the urea-denatured protein binding study, or ion molecules surrounding the imidazole rings of histidines are excluded, i.e., the dehydration or deion process of the proteins; (b) water or ion molecules surrounding the immobilized metal ions are excluded, i.e., the dehydration or decoordination process of the immobilized metal ions; (c) coordination interaction and/or nonspecific interaction, such as the electrostatic and hydrophobic interactions, is formed between the proteins and the immobilized metal ions; (d) the conformation of the proteins were rearranged upon adsorption and the accompanied hydration process; and (e) the excluded water or ion molecules in a bulk solution are rearranged. Specifically, to study the effects of the poly-histidine tail, the process of formation of coordination bonds ( i.e., the (c) process) was considered mainly for the difference, and for discussion of the effects of a denaturant, the dehydration or displacement of the denaturant processes of the proteins and adsorbents were emphasized.…”

“…As part of our recent work on the microcalorimetric studies of biomaterials at liquid/solid interfaces (19)(20)(21)(22)(23)(24)(25)(26)(27), mostly, in IMAC and hydrophobic interaction chromatography (HIC), and along with the attempt to further confirm the results mentioned above, this investigation, therefore, used the recombinant proteins, Schistosoma japonicum glutathione-S-transferase (SjGST) and SjGST/His (SjGST fused with a hexa-histidine tag) (28)(29)(30)(31)(32), as model proteins to study the interaction mechanisms in CP-IMAC by isothermal titration calorimetry (ITC) measurements. The binding topography of SjGST and SjGST/His with the Ni-NTA and TALON resins were also compared under either a native or denaturing condition.…”