Binding, cooperative

In the previous section, we discussed the case where the various binding sites were non-interacting in this section we consider the other limiting case where A is either free, or fully occupied by B as the species AB , and the intermediate states AB, AB2,. .., AB 2 and AB , are not populated. This behaviour arises because of positive interactions between the sites resulting in cooperative binding according to Eqn. 9.26, cooperative binding occurs when fC3 and K4 K2. The model considered here represents all or none behaviour, which is not just a theoretical model, but one which does actually occur with biopolymers. 

Introducing the conservation condition for A with the further assumption that cAB cB yields the following equation  

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Schwarz G 1970 Cooperative binding to linear biopolymers Eur. J. Blochem. 12 442-53... 

The Physiological Significance of Cooperative Binding of Oxygen by Hemoglobin... 

TOR Signalling. Figure 2 Dimeric structure of mTORCI and mTORC2. mTORCI contains mTOR, raptor and mLST8. Raptor binds the HEAT repeats of mTOR, mLST8 binds the kinase domain of mTOR. mTORC2 contains mTOR, rictor, Sini and mLST8. Rictor and Sini cooperatively bind the HEAT repeats of mTOR. 

Chitosan (> 75% deacelylation, 800-2000 cps) was mixed wilh stock so-lulions of Cu(II), Fe(ll), Cd(ll) and Zn(II), prepared in 0.1 M HNO3, and of Ca(ll) and Mn(II), in 0.1 MHCl. It was found that, in the chelation of most metal ions by chitosan, 1 1 binding of chitosan is more dominant than 2 1 cooperative binding, but vice versa for Zn(II) and Cd(II). The chelation of Cu(II) by chitosan showed much higher reactivity when compared to other divalent metal ions. Cu(II), Fe(II), Cd(II) andZn(II) showed strong reactivity and stability of their chelates. In contrast, the interactions between Ca(II) or Mn(II) and chitosan were almost negligible. These data confirm brilliantly previous data by Muzzarelli et al. [116]. 

Fig. 3.6 Polyamide-DNA binding motifs targeting longer DNA sequences. Overlapped and slipped homodimers depending on the sequence context, six-ring polyamides with central p-Ma residues can bind to DNA as fully overlapped homodimers, recognizing 11 bp, or as slipped homodimers, recognizing 13 bp. Extended hairpin extended conformation increases binding site size (to 9 bp) and enhances binding affinity. Cooperative dimer a cooperatively binding hairpin polyamide can...

An abasic peptide (Ac-Gys -Lys-(Ser-Ala-Ala-Lys)4-Ser-Gly-Lys-NH2) with unmodified Ser residues was synthesized and used as a control. No induced cooperative binding to. TAjGsAsT) was observed in the UV melting curve with this abasic peptide. This indicated that the cooperative melting between aPNA and its complementary DNA was not merely a reflection of nonspecific interactions be-... 

Hemoglobins bind four molecules of Oj per tetramer, one per heme. A molecule of Oj binds to a hemoglobin tetramer more readily if other Oj molecules are already bound (Figure 6-4). Termed cooperative binding, this phenomenon permits hemoglobin to maximize both the quantity of O2 loaded at the PO2 of the lungs and the quantity of O2 released at the PO2 of the peripheral tissues. Gooperative interactions, an exclusive property of multimeric proteins, are critically important to aerobic life. 

The Hill Equation Describes the Behavior of Enzymes That Exhibit Cooperative Binding of Substrate... 

An anticooperative mode of interactions was assumed in case of concave-shaped Scatchard plots, as alrea% proposed by other authors (Mattai Kwak, 1986 Gamier et al, 1994). A convexe curvature of the plots indicated a cooperative binding process (figure 4). 

Greene, L.E. (1986) Cooperative binding of myosin subfragment one to regulated acdn as measured by fluoresce changes of troponin 1 modified within different fluorophores./. Biol. Chem. 261, 1279. 

Complex binding reactions (more than one binding site for A on B, cooperative binding, etc.) can be described, e.g., by the Hill plot [154]. 

A report on the binding of the anesthetic propofol to human serum albumin and to plasma presents a dataset that challenges simple notions of equilibria [70]. The unbound fraction of propofol was found to increase sharply at low drug concentrations. The authors appear to have carefully eliminated possible artifacts. Explanations based on cooperative binding modes are discussed though no clear explanation emerges. 

Viles, J. H., Cohen, F. E., Prusiner, S. B., Goodin, D. B., Wright, P. E., and Dyson, H. J. (1999). Copper binding to the prion protein Structural implications of four identical cooperative binding sites. Proc. Natl. Acad. Sci. USA 96, 2042-2047. 

Figure 6.2. Proposed model for quinolone-DNA cooperative binding in the inhibition of DNA gyrase [32], (Reprinted with permission American Chemical Society.)...

When a ligand can complex more than one cation, the question arises of possible cooperative binding. There are many definitions of cooperativity but they are all consistent with the following criterion (Connors, 1987). A system is... 

Robertson A. and Shinkai S. (2000) Cooperative Binding in Selective Sensors, Catalysts and Actuators, Coord. Chem. Rev. 205, 157-99. 

Liu, G., M. Molas, G. A. Grossmann, M. Pasumarthy, J. C. Perales, M. J. Cooper, and R. W. Hanson. 2001. Biological properties of poly-L-lysine-DNA complexes generated by cooperative binding of the polycation. J Biol Chem 276(37) 34379-87. 

Adachi Y, Kas E, Laemmli UK (1989) Preferential, cooperative binding of DNA topoisomerase 11 to scaffold-associated regions. Embo J 8 3997 006... 

We briefly present here four different sources of long-range and nonadditivity of the cooperative binding of the X repressor to the operator. 

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