X-ray structure determination of a metastable state of carbonmonoxy myoglobin after photodissociation

摘要

The x-ray structure of carbon monoxide (CO)- ligated myoglobin illuminated during data collection by a laser diode at the wavelength λ = 690 nm has been determined to a resolution of 1.7 A at T = 36 K. For comparison, we also measured data sets of deoxymyoglobin and CO-ligated myoglo- bin. In the photon-induced structure the electron density asso- ciated with the CO ligand can be described by a tube extending from the iron into the heme pocket over more than 4 A. This density can be interpreted by two discrete positions of the CO molecule.