TY - JOUR
T1 - Global conformational changes in allosteric proteins
T2 - A study of Escherichia coli cAMP receptor protein and muscle pyruvate kinase
AU - Heyduk, Ewa
AU - Heyduk, Tomasz
AU - Lee, James C.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1992/2/15
Y1 - 1992/2/15
N2 - One of the basic features in allosteric regulation involves long range transduction of information. Based on crystallographic data on protein systems that are regulated by allosteric mechanisms, a global conformational change has always been observed. It is, therefore, important and useful to correlate the cooperativity of global structural change with the mode of binding of the regulatory ligand. Two systems were chosen for study, namely Escherichia coli cAMP receptor protein and muscle pyruvate kinase, which show negative and positive cooperativity in the binding of allosteric ligands, respectively. Quantitative titration of the global structural change, monitored by a high precision analytical gel chromatography technique, was conducted as a function of allosteric effector concentration. The results obtained for cAMP receptor protein show that the protein undergoes contraction upon binding of cAMP. The decreases in Stokes radius associated with complex formation are 0.1 ± 0.1 and 0.7 ± 0.1 Å when one and two cAMP-binding sites are filled, respectively. The results for the pyruvate kinase system show a concerted structural change that quantitatively match the predicted behavior based on equilibrium constants derived from the analysis of steady state kinetic data by a two-state model. Hence, for these two systems, these results show that negative and positive cooperativity are correlated with sequential and concerted modes of structural change, respectively.
AB - One of the basic features in allosteric regulation involves long range transduction of information. Based on crystallographic data on protein systems that are regulated by allosteric mechanisms, a global conformational change has always been observed. It is, therefore, important and useful to correlate the cooperativity of global structural change with the mode of binding of the regulatory ligand. Two systems were chosen for study, namely Escherichia coli cAMP receptor protein and muscle pyruvate kinase, which show negative and positive cooperativity in the binding of allosteric ligands, respectively. Quantitative titration of the global structural change, monitored by a high precision analytical gel chromatography technique, was conducted as a function of allosteric effector concentration. The results obtained for cAMP receptor protein show that the protein undergoes contraction upon binding of cAMP. The decreases in Stokes radius associated with complex formation are 0.1 ± 0.1 and 0.7 ± 0.1 Å when one and two cAMP-binding sites are filled, respectively. The results for the pyruvate kinase system show a concerted structural change that quantitatively match the predicted behavior based on equilibrium constants derived from the analysis of steady state kinetic data by a two-state model. Hence, for these two systems, these results show that negative and positive cooperativity are correlated with sequential and concerted modes of structural change, respectively.
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M3 - Article
C2 - 1737775
AN - SCOPUS:0026660254
SN - 0021-9258
VL - 267
SP - 3200
EP - 3204
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 5
ER -