Seibutsu Butsuri
Online ISSN : 1347-4219
Print ISSN : 0582-4052
ISSN-L : 0582-4052
Volume 40 , Issue 6
Issue 232
Showing 1-9 articles out of 9 articles from the selected issue
  • Chojiro KOJIMA, Masatsune KAINOSHO
    2000 Volume 40 Issue 6 Pages 379-384
    Published: 2000
    Released: April 26, 2001
    Hydrogen bonding plays an essential role in maintaining the structures and thus the functions of biological macromolecules, such as nucleic acids and proteins. Recently, scalar nuclear spin couplings (J couplings) across hydrogen bonds have been observed for various hydrogen bond pairs, such as N-H…N in nucleic acids and N-H…O=C in proteins. The coupling values range from 0.8 to 10Hz, depending on the systems and the interacting nuclei. As scalar couplings are known to be dominated by the Fermi contact term, these values can, in principle, be correlated to the nature of the hydrogen bonds.
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  • Koichi KOYAMA
    2000 Volume 40 Issue 6 Pages 385-390
    Published: 2000
    Released: April 26, 2001
    A differential response generated from a retinal protein, bacteriorhodopsin, at the electrode/electrolyte interface in an electrochemical cell was found to be a capacitive current caused by a potential change on the electrode that responds to a pH change arising from proton release and uptake during illumination of bacteriorhodopsin. The molecular mechanism for the proton-pumping of bacteriorhodopsin was rationalized by comparing capacitive currents of several mutant proteins that had been displaced the key amino acids for proton transfer. An extended study based on this method revealed that the other retinal proteins, halorhodopsin and phoborhodopsin, are also able to release and uptake protons under certain conditions.
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Experimental techniques
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