Spectroscopic dichroism

Choi S-W, Kawauchi S, Tanaka S, Watanabe J, Takezoe H (2007) Vibrational circular dichroism spectroscopic study on circularly polarized light-induced chiral domains in the B4 phase of a bent mesogen. Chem Lett 36 1018-1019... 

Pavel EG, Zhou J, Busby RW, Gunsior M, Townsend CA, Solomon El. Circular dichroism and magnetic circular dichroism spectroscopic studies of the non-heme ferrous active site in clavaminate synthase and its interaction with a-ketoglutarate cosubstrate. J. Am. Chem. Soc. 1998 120 743-753. 

A. Dong, J. Matsuura, S. D. Allison, E. Chrisman, M. C. Manning, and J. F. Carpenter, Infrared and circular dichroism spectroscopic characterization of structural differences between P-lactoglobulin A and B, Biochemistry 35.-1450-1457 (1996). 

A number of thiepane stereoisomers were reported by Cere and coworkers <05JOC664>. Detailed vibrational circular dichroism spectroscopic and ab initio DFT studies were then undertaken and the absolute configuration of 102 was assigned (shown for the (+) enantiomer) <05JOC664>. 

Mizutani T, Ema T, Yoshida T, Kuroda Y, Ogoshi H. Recognition of a-amino acid esters by zinc porphyrin derivatives via coordination and hydrogen bonding interactions. Evidence for two-point fixation from thermodynamic and induced circular dichroism spectroscopic studies. Inorg Chem 1993 32 2072-7. 

A detailed study by the same group, using nuclear magnetic resonance (NMR), Fourier transform ion cyclotron resonance (FTICR) and vibrational circular dichroism spectroscopic techniques, demonstrated that the use of different bases in place of the commonly used triethylamine significantly influenced the activity and selectivity of imine reductions. A key finding was that the protonated base appeared to interact with the hydride form of the catalyst during the reduction. 

Whitmore, L., Wallace, B.A. DICHROWEB, an online server for protein secondary structure analyses from circular dichroism spectroscopic data. Nucleic Acids Res. 32 (Web Server issue), W668-W673 (2004)... 

Clark PA, Solomon EL 1992. Magnetic circular dichroism spectroscopic definition of the intermediate produced in the reduction of dioxygen to water by native laccase. J Am C/jem c 114 1108-1110. 

Bauman D, Killet C, Boiadjiev SE, Lightner DA, Schonhofer A and Kuball H-G (1996) Linear and circular dichroism spectroscopic study of P, P -dimethylmesobilirubin-XIIIa oriented in a nematic liquid crystal. Journal of Physical Chemistry 100 11546-11558. 

H. M. Kwaambwa and R. Maikokera, Infrared and circular dichroism spectroscopic characterisation of secondary structure components of a water treatment coagulant protein extracted from Moringa oleifera seeds, Colloids and Surfaces B, vol. 64, no. 1, pp. 118—125, 2008. 

Molecular chirality is most often observed experimentally through its optical activity, which is the elfect on polarized light. The spectroscopic techniques for measuring optical activity are optical rotary dispersion (ORD), circular di-chroism (CD), and vibrational circular dichroism (VCD). 

The unmodified and complementary oligonucleotides were also synthesized, in order to detect thermodynamic and spectroscopic differences between the double helices. Circular dichroism spectra revealed that the covalently bound anthracene does not stack in the centre of the DNA double helix. Mutagenic activity by intercalative binding of the anthracene residue is thus unlikely. Only in vitro and in vivo replication experiments with site-specifically modified... 

Other spectroscopic methods such as infrared (ir), and nuclear magnetic resonance (nmr), circular dichroism (cd), and mass spectrometry (ms) are invaluable tools for identification and stmcture elucidation. Nmr spectroscopy allows for geometric assignment of the carbon—carbon double bonds, as well as relative stereochemistry of ring substituents. These spectroscopic methods coupled with traditional chemical derivatization techniques provide the framework by which new carotenoids are identified and characterized (16,17). 

The magnetic and electronic properties of the D. gigas Fdll [3Fe-4S] center were revealed by different and complementary spectroscopic techniques EPR 89), Mossbauer 90, 91), resonance Raman (RR) 92), magnetic circular dichroism MCD) 93), EXAFS 94), saturation magnetization (95), electrochemistry 96), and NMR (97, 98). The [4Fe-4S] center is also well characterized and surprising information has been obtained in relation to cluster interconversions and noncysteinyl coordination, as illustrated for D. gigas Fdl and D. africanus Fdlll, as well as the possibility of generating unusual reduced states. 

Other spectroscopic properties such as nuclear magnetic resonance (NMR), mass spectrometry (MS), infra-red (IR), and circular dichroism (CD) spectra of chlorophyll compounds and derivatives have been valuable tools for structural elucidation. - ... 

Of the visible spectroscopic techniques, CD spectroscopy has seen the most rapid and dramatic growth. The far-UV circular dichroism spectrum of a protein is a direct reflection of its secondary structure [71]. An asymmetrical molecule, such as a protein macromolecule, exhibits circular dichroism because it absorbs circularly polarized light of one rotation differently from circularly polarized light of the other rotation. Therefore, the technique is useful in determining changes in secondary structure as a function of stability, thermal treatment, or freeze-thaw. 

Determination of protein secondary structure has long been a major application of optical spectroscopic studies of biopolymers (Fasman, 1996 Havel, 1996 Mantsch and Chapman, 1996). These efforts have primarily sought to determine the average fractional amount of overall secondary structure, typically represented as helix and sheet contributions, which comprise the extended, coherent structural elements in well-structured proteins. In some cases further interpretations in terms of turns and specific helix and sheet segment types have developed. Only more limited applications of optical spectra to determination of tertiary structure have appeared, and these normally have used fluorescence or near-UV electronic circular dichroism (ECD) of aromatic residues to sense a change in the fold (Haas, 1995 Woody and Dunker, 1996). 

Analyses by native polyacrylamide gel electrophoresis and circular dichroism (CD) spectroscopy revealed that spontaneous coiled-coil associations between EGF-E5-His and EGF-K5-His promoted heterodimer (dEGF-His) formation. The CD spectroscopic analysis suggested that the E5 peptide in monomeric EGF-E5-His had a disordered structure. However, the ot-helical structure was induced in the E5 peptide when it associated with EGF-K5-His. These findings are shown schematically in Fig. 6. 

Two types of DNA binding sites. Two different spectroscopically distinct types of binding sites have been identified utilizing absorption, fluorescence and linear dichroism data on non-covalent (6), and covalent (7) pyrene-like metabolite model compound-DNA complexes. 

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