Our general goal has been to extend our understanding of macromolecular processes that are involved in the regulation and control of various biological events. To this end we have been primarily concerned with the thermodynamic description of ligand-linked processes that are amplified into various macromolecular changes. The physical-chemical properties of respiratory proteins are particularly suited for these studies. Due to its accessibility and the extensive knowledge of its properties, hemoglobin continues to play a central role in ligand control studies: a) Continue examination of ligand induced phase changes as exhibited by HbS. Some effort will be directed towards the search for triple point conditions where solution phase is in equilibrium with oxygenated and deoxygenated crystal phases. Examine the effect of non-hybridizing proteins, such as serum albumin, upon HbS solubility. b) Conduct heats of reaction measurements with O2 and CO upon trout hemoglobins and hemocyanins in collaboration with M. Brunori. Conduct parallel studies of oxygen binding curves with our thin layer cell, and parallel measurements of Bohr effects in our drop titrator. If the techniques give the expected precision, then an effort will be made to determine heats of reaction and Bohr proton release values as a function of extent of reaction. c) Examine general effects of DPG and IHP on oxygen binding curves to HbA under high concentration hemoglobin conditions with fixed DPG or IHP content in collaboration with G. Ackers. Determine proton release values and binding constants of IHP binding from direct titrations measurements. Determine effect of CO2 on oxygen binding curves of HbA.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Biophysics and Biophysical Chemistry A Study Section (BBCA)
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University of Colorado at Boulder
Schools of Arts and Sciences
United States
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Johnson, C R; Gill, S J (1993) A thin-layer gas-solution microcalorimeter for the determination of heat binding curves. Anal Biochem 209:150-5
Johnson, C R; Gill, S J; Peters, K S (1992) Thin-layer microcalorimetric studies of oxygen and carbon monoxide binding to hemoglobin and myoglobin. Biophys Chem 45:7-15
Johnson, C R; Ownby, D W; Gill, S J et al. (1992) Oxygen binding constants and stepwise enthalpies for human and bovine hemoglobin at pH 7.6. Biochemistry 31:10074-82
Vinogradov, S N; Sharma, P K; Qabar, A N et al. (1991) A dodecamer of globin chains is the principal functional subunit of the extracellular hemoglobin of Lumbricus terrestris. J Biol Chem 266:13091-6
Doyle, M L; Simmons, J H; Gill, S J (1990) Analysis of parameter resolution from derivatives of binding isotherms. Biopolymers 29:1129-35
Arp, A J; Doyle, M L; Di Cera, E et al. (1990) Oxygenation properties of the two co-occurring hemoglobins of the tube worm Riftia pachyptila. Respir Physiol 80:323-34
Ownby, D W; Gill, S J (1990) Nonlinear optical effects in oxygen-binding reactions of hemoglobin A0. Biophys Chem 37:395-406
Gill, S J; Doyle, M L; Simmons, J H (1989) Stabilization of the T-state of hemoglobin. Biochem Biophys Res Commun 165:226-33
Robert, C H; Colosimo, A; Gill, S J (1989) Allosteric formulation of thermal transitions in macromolecules, including effects of ligand binding and oligomerization. Biopolymers 28:1705-29
Di Cera, E; Bassi, F A; Gill, S J (1989) Information theory and the analysis of ligand-binding data. Biophys Chem 34:19-28

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