ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1327
    Keywords: Key words Ferredoxin ; Iron-sulfur clusters ; NMR ; Hyperfine shifts ; Magnetic interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  The oxidized Fe7S8 ferredoxin from Bacillus schlegelii, containing both [Fe3S4]+ and [Fe4S4]2+ clusters, has been investigated by 1H NMR spectroscopy. An extensive sequence-specific assignment of the hyperfine-shifted resonances has been obtained by making use of a computer-generated structural model. The pattern and the temperature dependence of the hyperfine shifts of the β-CH2 protons of the cysteines coordinating the [Fe3S4]+ cluster are rationalized in terms of magnetic interactions between the iron ions. The same approach holds for the hyperfine coupling with 57Fe. It is shown that the magnetic interactions are more asymmetric in Fe7S8 ferredoxins than in Fe3S4 ferredoxins. The NMR non-observability of the β-CH2 protons of coordinated cysteines in the one-electron-reduced form has been discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1572-8773
    Keywords: Copper ; Cobalt ; Nickel ; Superoxide dismutase ; Alkaline phosphatase ; NMR ; Relaxometry ; Nuclear relaxation ; Electronic relaxation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The water-proton nuclear-magnetic-relaxation dispersion profiles have been analyzed for Cu2Zn2-superoxide dismutase (SOD) and Cu2-alkaline phosphatase (AP). The electronic relaxation times are derived, together with structural information. The effect of magnetic coupling with another copper ion in Cu2Cu2SOD and Cu2Cu2AP is discussed. It is shown that the electronic relaxation times of copper(II) essentially do not change. The opposite happens with Cu2Co2SOD, Cu2Co2AP and Cu2Ni2SOD in which fast-relaxing metal ions provide relaxation mechanisms for copper(II) as well. In these cases the systems can be studied through high-resolution NMR spectroscopy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 31 (1993), S. S145 
    ISSN: 0749-1581
    Keywords: N MR Field cycling ; Relaxation ; Relaxometry ; Metal ions ; Biological systems ; Metalloproteins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper gives an overview of the impact of relaxometry in bioinorganic chemistry. It is taken from a lecture dedicated to Seymour H. Koenig that the author presented at the 5th Chianti Workshop in Magnetic Resonance, San Miniato, Pisa, Italy, May 30-June 5, 1993. After a short introduction and the definition of relaxometry, the basic principles of field-cycling relaxometry are illustrated, with reference to the Koenig-Brown relaxometer. Through a brief survey of early relaxometric data on paramagnetic solutions dating back to the 1950s and 1960s, attention is devoted to Koenig's discovery, in the 1970s, of anomalous relaxometric profiles of metalloprotein solutions and of the theoretical problems encountered in their interpretation. Then the advances made in the 1980s in the theory of electron nucleus interactions in slowly-rotating systems are summarized. These advances were largely due to the fruitful interactions between Koenig, Bertini and his group at the University of Florence and the author, first at the University of Florence and later at the University of Bologna. After a short digression on obtaining electron relaxation rates from relaxometric measurements and on their physical meaning, recent progresses in understanding the detailed relaxometric behaviour of aqueous solutions of paramagnetic metal ions are presented. Again, Koenig's physical insight into the phenomena is highlighted. Finally, the exciting perspectives of the 1990s in the field of contrast agents, particularly in the theoretical understanding of superparamagnets, where Koenig is again at the forefront, are briefly described.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...