Optical activity of proteins

Jirgensons, B. "Optical Activity of Proteins and Other Macromolecules", (1973) 2nd ed., pp. 77-122, Springer-Verlag, Berlin. 

B. Jirgensons, Optical Activity of Proteins and Other Macromolecules, 2nd.Ed., Springer-Verlag, New York, 1973. 

The above short survey on the far ultraviolet optical activity of proteins demonstrates the difficulties encountered in quantitative correlations between observed data and protein structures in solution nevertheless, conclusions may be reached in many cases, although with great caution and reservations. 

Then the multiterm Drude equation for the optical activity of proteins with varying conformation can be written as... 

FIGURE 8.5 Prof. Walter J. Kauzmann (1916-2009) was an American physical chemist whose research spanned thermodynamics (Kauzmann s paradox of supercooled hquids), quantum chemistry (1957 text), and biochemistry (the hydrophobic effect in enzymes). He was the Chair of Chemistry at Princeton University from 1964 to 1968 and the Chair of the Department of Biochemistry from 1980 to 1981. He is probably best known for his work on the thermodynamics and optical activity of proteins. (From Princeton University Department of Chemistry. With permission.)... 

Blauer G (1974) Optical Activity of Conjugated Proteins. 18 69-129 Bleijenberg KC (1980) Luminescence Properties of Uranate Centres in Solids. 42 97-128 Boca R, Breza M, Pelikan P (1989) Vibronic Interactions in the Stereochemistry of Metal Complexes 71 57-97... 

Let us consider first lipid-lipid interaction. Urry et al, showed the existence of a positive CD band at 218 m/x and a negative CD band at about 192 m/z in phosphatidyl choline and phosphatidyl ethanolamine dissolved in trifluoroethanol (86). The 192-m/z band was not characterized in detail, but the 218-m/z band is of such position and shape that the addition of lipid and protein CD bands could produce a composite CD band, and hence an ORD Cotton effect, which is red shifted. As noted by Urry, the 218-m/z CD extremum of lecithin must arise from n — 7T transitions in the fatty acid ester groups. Although the optical activities of solutions of deproteinized membrane phospholipids determined at the same concentration as in the intact membrane are negligibly small, in membranes an ordered array of lipids could greatly enhance rotation. Such an effect could yield information on the nature of lipid-lipid association. This can be tested experimentally. Halobacterium cutirubrum offers a unique system since Kates has shown that the lipids in this extreme halophile contain ether bonds rather than ester bonds (43, 44), Hence, the n — tt transition essential to the CD band at 218 m/z in phospholipids does not exist. Nevertheless, we found that the ORD... 

These results consistently indicate that the three non-heme iron proteins exhibit multiple Cotton effects. Their ORD also shows these effects. Further, it is seen that the optical activity of the three proteins is very similar, differing only by minor shifts in wavelength and intensity of the individual components. This striking similarity leads us to believe that the stereospecific configuration of the iron chromophore is essentially identical in these proteins. However, the behavior of these proteins differs... 

In addition, these results strongly suggest that the changes in optical activity of the chromophore during the oxidation-reduction cycle are related to the catalytic function of the protein and that the structure of the oxidized chromophore differs from that of the reduced one. 

Wen et al. (1994) investigated the Raman optical activity of poly-L-lysine both as the random coil and the a-helix. They compared these spectra to the spectra of bovine serum albumin and insulin and arrived at the conclusion that tertiary structure of proteins can be readily deduced from the ROA spectra. 

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