Allosteric theory

Hemoglobin ◽  
2018 ◽  
pp. 42-57
Author(s):  
Jay F. Storz
Keyword(s):  
Active Site ◽  
Binding Sites ◽  
Allosteric Regulation ◽  
Theoretical Models ◽  
State Model ◽  
Regulatory Control ◽  
Indirect Interaction ◽  
Protein Activity ◽  
Conformational States ◽  
Two State Model

Chapter 3 provides a brief overview of allostery, the modulation of protein activity that is caused by an indirect interaction between structurally remote binding sites. In this mode of intramolecular regulatory control, the binding of ligand at a protein’s active site is influenced by the binding of another ligand at a different site in the same protein. This interaction at a distance is mediated by a ligation-induced transition between alternative conformational states. Hemoglobin is regarded as the “allosteric paradigm,” and the oxygenation-linked transition between alternative quaternary conformations provides a textbook example of how allostery works. This chapter reviews different theoretical models, such as the Monod-Wyman-Changeux “two-state” model, to explain the allosteric regulation of hemoglobin function.

Allosteric regulation of aspartate transcarbamoylase. Analysis of the structural and functional behavior in terms of a two-state model

Biochemistry ◽  
1977 ◽  
Vol 16 (23) ◽  
pp. 5091-5099 ◽  
Author(s):  
G. J. Howlett ◽  
Michael N. Blackburn ◽  
John G. Compton ◽  
H. K. Schachman
Keyword(s):  
Allosteric Regulation ◽  
State Model ◽  
Aspartate Transcarbamoylase ◽  
Functional Behavior ◽  
Two State Model

scholarly journals Computing DNA duplex instability profiles efficiently with a two-state model: trends of promoters and binding sites

2010 ◽  
Vol 11 (1) ◽  
Author(s):  
Miriam R Kantorovitz ◽  
Zoi Rapti ◽  
Vladimir Gelev ◽  
Anny Usheva
Keyword(s):  
Binding Sites ◽  
State Model ◽  
Dna Duplex ◽  
Two State Model

scholarly journals A model for the allosteric regulation of pH-sensitive enzymes

1977 ◽  
Vol 167 (2) ◽  
pp. 479-482 ◽  
Author(s):  
J S Shindler ◽  
K F Tipton
Keyword(s):  
Active Site ◽  
Binding Sites ◽  
Initial Rate ◽  
Allosteric Regulation ◽  
Ionization Constants ◽  
Allosteric Control ◽  
Ph Values ◽  
Regulatory Enzymes ◽  
Or Groups ◽  
Catalytically Active

1. In an enzyme that has two independent binding sites for a ligand, any inhibitor that binds solely to the free enzyme will give rise to positive co-operativity. 2. A model is considered for the allosteric control of enzymes by effectors in which their effects are mediated by ligand-induced perturbations of the ionization constants of a group or groups involved in the binding of substrate to the active site. 3. The model described offers a plausible explanation for the observation that the sigmoidal initial-rate curves reported for some regulatory enzymes are not expressed at all pH values where the enzyme is catalytically active.

scholarly journals The mechanism of thin filament regulation: Models in conflict?

2019 ◽  
Vol 151 (11) ◽  
pp. 1265-1271 ◽  
Author(s):  
Michael A. Geeves ◽  
Sherwin S. Lehrer ◽  
William Lehman
Keyword(s):  
Rate Constant ◽  
Binding Sites ◽  
Thin Filament ◽  
State Model ◽  
Muscle Contractility ◽  
Thin Filaments ◽  
Thin Filament Regulation ◽  
Three State Model ◽  
State Models ◽  
Two State Model

In a recent JGP article, Heeley et al. (2019. J. Gen. Physiol. https://doi.org/10.1085/jgp.201812198) reopened the debate about two- versus three-state models of thin filament regulation. The authors review their work, which measures the rate constant of Pi release from myosin.ADP.Pi activated by actin or thin filaments under a variety of conditions. They conclude that their data can be described by a two-state model and raise doubts about the generally accepted three-state model as originally formulated by McKillop and Geeves (1993. Biophys. J. https://doi.org/10.1016/S0006-3495(93)81110-X). However, in the following article, we follow Plato’s dictum that “twice and thrice over, as they say, good it is to repeat and review what is good.” We have therefore reviewed the evidence for the three- and two-state models and present our view that the evidence is overwhelmingly in favor of three structural states of the thin filament, which regulate access of myosin to its binding sites on actin and, hence, muscle contractility.

Polarographic studies on renaturation of urea-denatured human serum albumin

1989 ◽  
Vol 54 (2) ◽  
pp. 536-543 ◽  
Author(s):  
Josef Chmelík ◽  
Pavel Anzenbacher ◽  
Vítěz Kalous
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Irreversible Process ◽  
State Model ◽  
Native Protein ◽  
Main Components ◽  
Two State Model ◽  
Kinetics Of

The renaturation of the two main components of human serum albumin, i.e. of mercaptalbumin and nonmercaptalbumin, was studied polarographically. It has been demonstrated that renaturation of both proteins after 1-min denaturation in 8M urea is reversible. By contrast, renaturation after 200 min denaturation in 8M urea is an irreversible process; the characteristics of renatured mercaptalbumin differ more from the properties of the native protein than the characteristics of nonmercaptalbumin. The studies of the kinetics of renaturation of both proteins have shown that the renaturation can be represented by a two-state model. This means that the existence of stable intermediary products during the renaturation process was not determined polarographically.

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