Biomolecules significance

Optimized potentials for liquid simulation (OPES) was designed for modeling bulk liquids. It has also seen significant use in modeling the molecular dynamics of biomolecules. OPLS uses five valence terms, one of which is an electrostatic term, but no cross terms. 

The covalent bond is the strongest force that holds molecules together (Table 2-1). Noncovalent forces, while of lesser magnitude, make significant contributions to the structure, stability, and functional competence of macromolecules in living cells. These forces, which can be either attractive or repulsive, involve interactions both within the biomolecule and between it and the water that forms the principal component of the surrounding environment. 

Fluid-phase uptake of macromolecules by cells in general is a slow process, and most administered macromolecules are eliminated from the host before any significant cellular uptake takes place. If, however, the macromolecule contains a moiety that is compatible with a receptor on a specific cell surface, then the macromolecule is attracted to the cell surface and the uptake is enhanced. This maximizes the opportunity for specific-cell capture. This type of cell-specific targeting has been developed to hepatocytes, with galactosamine to T lymphocytes, with anti-T cell antibodies and to mouse leukemia cells, with fucosylamine and other biomolecules. 

As with conductivity measurements, methods and results of theoretical treatments of CT in DNA have varied significantly. Mechanisms invoking hopping, tunneling, superexchange, or even band delocalization have been proposed to explain CT processes in DNA (please refer to other reviews in this text). Significantly, many calculations predicted that the distance dependence of CT in DNA should be comparable to that observed in the a-systems of proteins [26]. This prediction has not been realized experimentally. The dichotomy between theory and experiment may be related to the fact that many early studies gave insufficient consideration to the unique properties of the DNA molecule. Consequently, CT models derived for typical conductors, or even those based on other biomolecules such as proteins, were not adequate for DNA. 

Metastable atom bombardment (MAB) is a novel ionization method for mass spectrometry invented by Michel Bertrand s group at the University of Montreal, Quebec, Canada, and described by Faubert et al.38 For the identification of bacteria by MS, MAB has a number of significant advantages relative to more familiar ionization techniques. Electron ionization (El) imparts so much excess energy that labile biomolecules break into very small fragments, from which the diagnostic information content is limited since all... 

This brief anecdote should serve to illustrate that its extensively interdisciplinary character is not only a strength of bio-EPR but also its Achilles heel. When the production of significant results requires comparable input efforts from different disciplines, there is an increased chance for the occurrence of time-wasting misunderstandings and errors. A less anecdotic example is the claim—frequently found in physics texts—that sensitivity of an EPR spectrometer increases with increasing microwave frequency. Although this statement may in fact be true for very specific boundary conditions—for example, when sensitivity stands for absolute sensitivity of low-loss samples of very small dimensions—when applied in the EPR of biological systems it can easily lead to considerable loss of time and money and to frustration on the part of the life science researcher, because it is simply not true at all for (frozen) solutions of biomolecules. 

---