NMR in biological systems

Bertini, L Luchinat, C. NMR of Paramagnetic Molecules in Biological Systems ... 

Cannel, R.J.P., Rashid, T., Ismail, I.N. et al. (1997) Novel metabolites of warfarin produced by Beauveria bassiana and Streptomyces rimosus a novel application of HPLC-NMR. Xenobiotica The Fate of Foreign Compounds in Biological Systems, 27, 147-157. 

Lately, the CP-MD approach has been combined with a mixed QM/MM scheme [10-12] which enables the treatment of chemical reactions in biological systems comprising tens of thousands of atoms [11, 26]. Furthermore, CP-MD and mixed QM/MM CP-MD simulations have also been extended to the treatment of excited states within a restricted open-shell Kohn-Sham approach [16, 17, 27] or within a linear response formulation of TDDFT [16, 18], enabling the study of biological photoreceptors [28] and the in situ design of optimal fluorescence probes with tailored optical properties [32]. Among the latest extensions of this method are also the calculation of NMR chemical shifts [14]. 

In biological systems, H-bond donors and acceptors are predominantly nitrogen and oxygen atoms. However, the n electrons of aromatic systems can also act as acceptors, and H-bonds involving sulfur groups or metallic cofactors are also known. The presence of individual H-bonds in biomacromolecular structures is usually derived from the spatial arrangement of the donor and acceptor groups once the structure of a molecule has been solved by diffractive or NMR techniques. More detailed information about H-bonds... 

Band, L. Bertini, I. Luchinat, C. Nuclear and Electron Relaxation , VCH Weinheim 1991. Bertini, I. Luchinat, C. NMR of Paramagnetic Molecules in Biological Systems , Benjamin/ Cummings Menlo Park CA, 1986. 

A coirplete understanding of the role of carbohydrates in biological systems requires knowledge of the distribution at equilibrium of the various conformers in aqueous solution. The conformational behavior of carbohydrates in solution can be examined from different vantage points (1,), but the most relevant approach is, no doubt, study of dilute solutions themselves. At present, high resolution NMR spectroscopy is the primary tool for determination of three-dimensional structure of oligosaccharides in solution. Optical rotation is also very sensitive to conformation (2) and there is a new, semi-enqpirical theory of optical rotation of oligosaccharides ( ). 

The present volume comprises 17 chapters, written by 27 authors from 11 countries, and deals with theoretical aspects and structural chemistry of peroxy compounds, with their thermochemistry, O NMR spectra and analysis, extensively with synthesis of cyclic peroxides and with the uses of peroxides in synthesis, and with peroxides in biological systems. Heterocyclic peroxides, containing silicon, germanium, sulfur and phosphorus, as well as transition metal peroxides are treated in several chapters. Special chapters deal with allylic peroxides, advances in the chemistry of dioxiranes and dioxetanes, and chemiluminescence of peroxide and with polar effects of their decomposition. A chapter on anti-malarial and anti-tumor peroxides, a hot topic in recent research of peroxides, closes the book. 

CD and ORD have also been employed to detect conformational properties of acyl heterocycles in optically active molecules especially in biological systems. These techniques have been employed, for example, in the conformational study of proline derivatives (70MI2 70M13 73BCJ3894), and as complementary approaches to NMR measurements. 

Previous books on NMR of paramagnetic molecules are G.N. La Mar, W.DeW. Horrocks, Jr. and R.H. Holm (Eds.) (1973) NMR of Paramagnetic Molecules. Academic Press, New York. I. Bertini and C. Luchinat (1986) NMR of Paramagnetic Molecules in Biological Systems. Benjamin-Cummings, Menlo Park. 

NMR studies of porphyrin-containing iron(III) complexes are very many owing to their importance in biological systems. The porphyrin systems are tetradentate dianionic ligands and essentially planar, as reported in Fig. 5.7, and allows easy access of monodentate ligands to both the axial coordination positions [15]. 

I. Bertini, C. Luchinat (1986) NMR of paramagnetic molecules in biological systems. Benjamin/Cummings, Menlo Park, CA. 

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