Light-induced relaxation of photolyzed carbonmonoxy myoglobin: a temperature-dependent x-ray absorption near-edge structure (XANES) study.

ABSTRACT: X-ray absorption near-edge structure (XANES) spectra at the Fe K-edge have been measured and compared on solution samples of horse carbonmonoxy-myoglobin and its photoproducts, prepared by two different photolysis protocols: 1), extended illumination at low temperature (15 K) by white light; and 2), slow-cool from 140 to 10 K at a rate of 0.5 K/min while illuminating the sample with a 532-nm continuous-wave laser source. CO recombination has been followed while increasing the temperature at a rate of 1.2 K/min. After extended illumination at 15 K, a single process is observed, corresponding to CO recombination from a completely photolyzed species with CO bound to the primary docking site (formally B-state, in agreement with previous x-ray diffraction studies). The temperature peak for this

SUBMITTER: Arcovito A 

PROVIDER: S-EPMC1305389 | biostudies-literature | 2005 Apr

REPOSITORIES: biostudies-literature