ABSTRACT
The dynamics of selected conformational coordinates, key roles in the understanding of the CO-rebinding process, are investigated in horse heart carbonmonoxy myoglobin (MbCO) through time-resolved X-ray absorption spectroscopy. We present here the results obtained at 90 K in the second time scale. The approach of the CO molecule towards the Fe atom in the active site pocket is speculated to act as a natural precursor to the Fe displacement with the consequent undoming of the protein porphyrin plane. The arrangement of the Fe-C-O bonding angle geometry follows and the final MbCO active site configuration is completely reached within 1 min.
Subject(s)
Myoglobin/chemistry , Myoglobin/metabolism , Absorptiometry, Photon/methods , Animals , Carbon Monoxide/metabolism , Horses , Kinetics , Myocardium/metabolism , Protein Conformation , Time FactorsABSTRACT
Inverse x-ray fluorescence holography was used to explore the local atomic order of a nearly perfect quasicrystal with composition Al70. 4Pd21Mn8.6. We have demonstrated the possibility of direct 3D imaging of the atomic decoration in a quasicrystal. We have obtained the average 3D environment of selected coordination shells around the Mn atoms. These results open the way to obtaining further and more complete information about the various coordination shells in complex materials by measuring multiple energy x-ray holograms at different sites.
ABSTRACT
Contiene: Identificación de los mayores problemas y dificultades que afectan al sector forestal. Lineamientos para la asistencia futura PNUD/FAO al sector forestal. Anexos
