Time Resolved Synchrotron Radiation Circular Dichroism Spectroscopy

Presents an account of circular dichroism (CD) spectroscopy and its application to structural biology. This book covers the methods of synchrotron radiation circular dichroism (SRCD) and linear dichroism (LD).

viii The experimental research presented at the conference and reported here deals mainly with the visible wavelength region and slight extensions to either side (roughly from 150 nrn to 1000 nrn, 8. 3 eV to 1. 2 eV). A single exception was that dealing with a description of spin-resolved photoelectron spectroscopy at energies up to 40 eV (31 nm). This work was done using circularly polarized radiation emitted above and below the plane of the circulating electrons in a synchrotron ring. The device at BESSY (West Germany) in which the experiments were carried out seems to be the only one presently capable of providing circularly polarized radiation in the X--ray through vacuum ultraviolet energy range. A much more intense source is needed in this range. A possible solution was proposed which could provide not only circularly polarized photons over a wide energy range, but could in principle modulate the polarization of the beam between two orthogonal polarization states. Realization of this device, or an equivalent one, would be a vital step towards the goal of determining all components of the Mueller matrix for each spectroscopic experiment. A variety of theoretical treatments are presented describing the different phenomena emerging from the interaction of matter and polarized radiation in a wide range of energies. From this work we expect to learn what are the most useful wavelength regions and what types of samples are the most suitable for study.

''Excellent and very timely....It will undoubtedly become a standard reference for the application of circular dichroism (CD) to biomolecules.'' --- Quarterly Review of Biology, March 1997 ''[T]estament to the book's utility is the fact that during the course of my review I had to 'rescue' it from the desks of graduate students on an almost daily basis. In summary, this is a great book.'' --- American Scientist ''Well documented chapters provide a very good insight into the problems surrounding the conformation of biomacromolecules...An indispensible source of information.'' --- Nahrung, 42(2), 1998 Renowned experts present the first state-of-the-art description of circular dichroism spectroscopy (CD). Chapters present in-depth discussions of the history of the field, the theory of CD for application to globular proteins, membrane proteins, peptides, nucleic acids and their interactions, carbohydrates, and instrumentation. Discussions also feature new techniques using synchrotron radiation, vibrational Raman optical activity, and vibrational CD. More than 250 illustrations supplement the text.

Work performed at the Stanford Synchrotron Radiation Laboratory (SSRL) is reported. The timing characteristics of the SPEAR beam (pulse width less than or equal to 0.4 nsec, pulse repetition period = 780 nsec) were exploited to determine dynamic behavior of atomic, molecular, excimeric, and photodissociative gas-phase species excited by vacuum-ultraviolet (VUV) radiation. Fast fluorescence timing measurements were done to determine excited-state lifetimes of Kr and Xe. Pressure-dependent timing studies on Xe gas at higher concentrations demonstrated some of the problems associated with previous kinetic modeling of the Xe2 system. It was found that even qualitative agreement of observed Xe2 lifetimes as a function of pressure required the assumption that the radiative lifetime was a strong function of internuclear separation. The radiative decays of chemically unstable fragments, CN* (B2.sigma.) and XeF* (B2.sigma. and C2 Pi32/), were studied by pulsed photodissociation of stable parent compounds, ICN and XeF2. When the polarization of the CN* (B2.sigma./sup +/) fragment fluorescence was measured, it was found to be non-zero and strongly dependent on excitation wavelength. This polarization is related to the symmetry of the photodissociative surface via a classical model, and the variations in the polarization with wavelength is attributed to symmetry and lifetime effects of a predissociating parent molecule. Despite the drawbacks of limited availability and low radiation flux, synchrotron radiation is definitely a useful spectroscopic tool for VUV studies of gas-phase systems.

With three Nobel Laureates contributing to this invaluable collection of high-quality articles, carefully selected from the highly praised R.A. Meyer's Encyclopedia, these two volumes cover a wide range of topics in protein research. Clearly divided into sections on structure, modeling, expression, analysis and others, the chapters are designed to aid readers of all levels of expertise: Each chapter includes a glossary of the most important keywords, a concise summary of the article concerned and comprehensive references for further reading. Similarly, the uniform structure of the articles makes them very easy to use, resulting in a ready reference for molecular and cell biologists, biochemists, biophysicists, and biotechnologists, as well as those working in the pharmaceutical and biotechnological industries.