Recognition forces

Recognition Forces and Molecular Interaction Fields (MIFs)... 

The stereoelectronic features produce actions at a distance by the agency of the recognition forces they create. These forces are the hydrophobic effect, and the capacity to enter ionic bonds, van der Waals interactions and H-bonding interactions. The most convenient and informative assessment of such recognition forces is afforded by computahon in the form of MIFs, e.g. lipophilicity fields, hydrophobicity fields, molecular electrostatic potentials (MEPs) and H-bonding fields (see Chapter 6) [7-10]. 

Ermondi, G., Caron, G. Recognition forces in ligand-protein complexes. Biochem. Pharmacol. 2006, 72,... 

A strategy for an experimental study of weak molecular recognition forces has been reported by Wilcox and coworkers [139]. From the equilibrium shown in Figure 106, the edge-to-face interaction was estimated to be of the order of 0.5 kcal mol . Interestingly, aliphatic groups such as cyclohexyl and r-butyl also showed preference for the folded conformation. 

Kada, G., Blayney, L., Jeyakumar, L. H., Kienberger, F, Pastushenko, V. R, Fleischer, S., Schindler, H., Lai, F. A., and Hinterdorfer, P. 2001. Recognition force microscopy/spectroscopy of ion channels Applications to the skeletal muscle Ca2-l- release channel (ryrl). Ultramicroscopy 86,129-137. 

Hinterdorfer P, Gruber HJ, Kienberger F, Kada G, Riener C, Borken C, et al. Surface attachment of ligands and receptors for molecular recognition force microscopy. Colloid Surface B. 2002 23(2-3) 115-23. 

Lower BH et al (2009) Antiobody recognition force microscopy shows the outer membrane cytochromes omcA and MtrC are expressed on the exterior surface of Shewanella oneidensis MR-1. Appl Environ Microbiol 75(9) 2931-2935... 

Because of their intellectual and practical importance, and their aesthetic beauty, chemists have longed to mimic such large, multimolecular complexes. The phrase supramolecular chemistry—chemistry beyond the molecule—has been coined to describe this field. Certainly, the host-guest systems we discussed above are simple examples of supramolecules, and the molecular recognition forces we ve enumerated will provide the driving force for assembly. But, when a large number of molecules assembles into one complex system, new issues arise. Here we will summarize some of the general issues associated with supramolecular chemistry, and then we will present some examples of especially successful or informative systems. 

B. Catenane formation using the molecular recognition forces involved in the complex in part A. 

Most of the work reviewed above has been based on measurements carried out with force spectroscopic experiments. An in )ortant development and step forward to the integration of the nanobiotribological measurements in biomedical research has been accomplished by creating specific adhesion force and friction interactions images by probing recognition forces between biological conqjlexes (91-94). 

Figure 1 A comparison between recognition forces in molecular pharmacology and biology [left) and intermolecular forces encoded in lipophilicity (right). (Ref. 40.)...

Such an expression allows comparison of molecular recognition forces with the interactions encoded in lipophilicity. This is done in Figure 1, where the polar component of lipophilicity is seen to correspond to ion—dipole bonds, hydrogen bonds, orientation forces, and induction forces, whereas the hydrophobic component corresponds to dispersion forces and hydrophobic interactions. Only a limited number of recognition forces cannot find expression in lipophilicity as conventionally measured, namely, ionic bonds, charge transfer interactions, and aryl/aryl stacking interactions. ... 

Moreover, and as expected from the foregoing discussion on recognition forces, the precision of lipophilicity calculations is expected to be greatly improved if intramolecular interaaions are taken into account. However, a full... 

Based on the explicit treatment of the most important intermolecular interactions (i.e., steric and electrostatic), 3D-QSAR techniques have flourished in the field of ligand—receptor interactions.Because of the interconnection between recognition forces and intermolecular interactions encoded in lipophilicity (Figure 1), the benefits of these techniques in the prediction of partition coefficients from the 3D structure were explored. 

CharM Transfer Binding As a Recognition Force to Form Pseudorotaxanes... 

The relationship between tautomerism and biological activity is very important, although still unclear, because no serious experimental studies have been carried out. The problem can be modeled by a host-guest situation (Figure 1.1), considering that molecular recognition forces will discriminate between tautomers. 

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