Français
Albanian
Arabic
Armenian
Azerbaijani
Belarusian
Bengali
Bosnian
Catalan
Czech
Danish
Deutsch
Dutch
English
Estonian
Finnish
Français
Greek
Haitian Creole
Hebrew
Hindi
Hungarian
Icelandic
Indonesian
Irish
Italian
Japanese
Korean
Latvian
Lithuanian
Macedonian
Mongolian
Norwegian
Persian
Polish
Portuguese
Romanian
Russian
Serbian
Slovak
Slovenian
Spanish
Swahili
Swedish
Turkish
Ukrainian
Vietnamese
Български
中文(简体)
中文(繁體)
Biochemistry 1995-Mar

Spectroscopic evidence for the symmetric location of tyrosines D and Z in photosystem II.

Seuls les utilisateurs enregistrés peuvent traduire des articles
Se connecter S'inscrire
Le lien est enregistré dans le presse-papiers
D Koulougliotis
X S Tang
B A Diner
G W Brudvig

Mots clés

Abstrait

Saturation-recovery EPR spectroscopy has been used to probe the location of the redox-active tyrosines, YD (tyrosine 160 of the D2 polypeptide, cyanobacterial numbering) and YZ (tyrosine 161 of the D1 polypeptide), relative to the non-heme Fe(II) in Mn-depleted photosystem II (PSII). Measurements have been made on PSII membranes isolated from spinach and on PSII core complexes purified from the cyanobacterium Synechocystis sp. PCC 6803. In the case of Synechocystis PSII, site-directed mutagenesis of the YD residue to either phenylalanine (Y160F) or methionine (Y160M) was done to eliminate the dark-stable YD.species and, thereby, allow direct spectroscopic observation of the YZ. EPR signal. The spin-lattice relaxation transients of both YD. and YZ. were non-single-exponential due to a dipolar interaction with one of the other paramagnetic species in PSII. Measurements on CN(-)-treated, Mn-depleted cyanobacterial PSII, in which the non-heme Fe(II) was converted into its low-spin, diamagnetic state, proved that the non-heme Fe(II) was the sole spin-lattice relaxation enhancer for both the YD. and YZ. radicals. This justified the use of a dipolar model in order to fit the saturation-recovery EPR data, which were taken over the temperature range 4-70 K. The dipolar rate constants extracted from the fits were identical in magnitude and had the same temperature dependence for both YD. and YZ.. The observation of identical dipolar interactions between YD. and YZ. and the non-heme Fe(II) shows that the distance from each tyrosine to the non-heme Fe(II) is the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Rejoignez notre
page facebook

La base de données d'herbes médicinales la plus complète soutenue par la science

  • Fonctionne en 55 langues
  • Cures à base de plantes soutenues par la science
  • Reconnaissance des herbes par image
  • Carte GPS interactive - étiquetez les herbes sur place (à venir)
  • Lisez les publications scientifiques liées à votre recherche
  • Rechercher les herbes médicinales par leurs effets
  • Organisez vos intérêts et restez à jour avec les nouvelles recherches, essais cliniques et brevets

Tapez un symptôme ou une maladie et lisez des informations sur les herbes qui pourraient aider, tapez une herbe et voyez les maladies et symptômes contre lesquels elle est utilisée.
* Toutes les informations sont basées sur des recherches scientifiques publiées

Google Play badgeApp Store badge