Biological systems, resonance Raman spectroscopy

By tuning the laser source to the absorption maximum of the chromophore, the Raman spectrum obtained is the enhanced spectrum of that chromophore with little interference from the dense vibration modes of the protein or the water itself. For a quantitative discussion of resonance Raman spectroscopy (14) and its application to biological systems (15), the reader is referred to other papers. 

Iron chlorin complexes have been studied by resonance Raman spectroscopy. Observations have predictive value, and offer criteria for an identification of metallochlorin prothetic groups in biological systems (85JA182). 

Resonance Raman spectroscopy of biochemical and biological systems... 

The great interest in resonance Raman spectroscopy as probe for studying biological systems still continues. Very recent results can be extracted from the biannual proceedings of the international Raman conferences (Durig and Sullivan, 1990 Kiefer et al., 1992 Yu and Li, 1994) and from the conferences on the spectroscopy of biological molecules (Bertoluzza et al., 1989 Hester and Gerling, 1991 Theophanides et al., 1993). 

Perturbation or difference experiments provide another method for simplifying the data in both Raman and IR experiments. The classic approach is to introduce isotopic substitutions which identify the chemical groups responsible for the vibration and permit vibrational normal mode assignments. Chemical modification of the prosthetic group or of the protein and amino acid mutation are additional possibilities. Temperature jump, pressure jump, and rapid mixing experiments are also valuable approaches. This introduction emphasizes the use of time-resolved vibrational spectroscopy to examine the vibrational information selectively. It is not possible in this chapter to describe all of the possible ways to study biological systems using vibrational spectroscopy. Examples of the use of resonance Raman spectroscopy to study the structure and... 

Time-Resolved Resonance Raman Spectroscopy (TR S) is a technique used to get structural, kinetic, and molecular interaction data from chemical and biological systems by recording resonance Raman spectra in a short time span. Using TR S, a transient molecular species can be analyzed by (i) monitoring the frequency of vibrational... 

A major advantage of Raman spectroscopy for the analysis of biomolecules stems from the fact that water has a weak Raman spectrum. Spectra can be recorded for aqueous solutes at 10 -10 M with little interference from the solvent. For a chromophore under the RR condition the accessible concentration range becomes 10 " -10 M. Moreover, the intensity enhancement associated with the RR effect confers the important advantage of selectivity, allowing one to observe selectively the vibrational spectrum of a chromophore that is just one component of an extremely complex biological system. Because many biomolecules have chromophores with an ultraviolet (UV) resonance condition, one may also selectively excite a chromophore by irradiating these molecule with UV light. This technique is known as Ultraviolet Resonance Raman Spectroscopy (UVRRS). In recent years, Raman difference spectroscopy (RDS) has been developed in... 

NMR, EPR, EXAFS, infrared, resonance Raman, and ultraviolet-visible spectroscopy should follow. Kinetic and thermodynamic information about the model complexes in comparison to that known for natural systems should be gathered. These concepts were updated in 1999 by Karlin, writing in reference 49. Model studies should provide reasonable bases for hypotheses about a biological structure and its reaction intermediates. Researchers should determine the model s competence in carrying out reactions that mimic metalloprotein chemistry. Using these methods and criteria, researchers may hope to exploit Cu-oxygen systems as practical dioxygen carriers or oxidation catalysts for laboratory and industrial purposes. 

Many other methods have been employed to study CTC in biological systems, such as calorimetry, mixed fusion analysis, solubility and partition methods, ultrasonic methods, spectropolarimetry, reflective infrared spectroscopy, Raman spectroscopy, flash photolysis spectroscopy, nuclear quadrupole resonance spectroscopy, and magnetic susceptibility methods, to name several of a very long list. X-ray photoelectron spectroscopy (XPS) has also been used to elucidate some EDA interactions in electrically active macromolecules. XPS is useful for detecting the redistribution of charges in complexes of such compounds, (e.g., in the presence of phosphate acceptors, the nature of the semiconductive environment of S, O, and N bridges in macromolecules is affected profoundly [111]. 

Carey PR, Salares VR (1980) Raman and resonance Raman studies of biological systems. In Clark RJH, Hester RE (eds) Advances in Infrared and Raman spectroscopy, vol 7. p 1 Heyden and Sons, London... 

T. G. Spiro and T. M. Loehr, Resonance Raman Spectra of Heme Proteins and Other Biological Systems, in Advances in IR and Raman Spectroscopy , eds. R. J. H. Clark and R. E. Hester, John Wiley Sons, New York, 1975, Vol. 1, p. 98. 

The second volume of this new treatise is focused on the physicochemical properties and photochromic behavior of the best known systems. We have included chapters on the most appropriate physicochemical methods by which photochromic substances can be studied (spectrokinetic studies on photostationary states, Raman spectroscopy, electron paramagnetic resonance, chemical computations and molecular modeling, and X-ray diffraction analysis). In addition, special topics such as interactions between photochromic compounds and polymer matrices, photodegradation mechanisms, and potential biological applications have been treated. A final chapter on thermochromic materials is included to emphasize the chemical similarities between photochromic and thermochromic materials. In general, the literature cited within the chapters covers publications through 1995. However, in several cases, publications from as late as 1997 are included. 

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