Time-resolved circular dichroism in carbonmonoxy-myoglobin: the central role of the proximal histidine.

Chirality

Laboratoire d'Optique et Biosciences, CNRS-INSERM, Ecole Polytechnique, 91128 Palaiseau cedex, France.

Published: May 2006

A calculation of the circular dichroism (CD) spectra of carbonmonoxy- and deoxy-myoglobin is carried out in relation to a time-resolved CD experiment. This calculation allows us to assign a dominant role to the proximal histidine in the definition of the electronic normal modes and to interpret the transient CD structure observed in a strain of the proximal histidine. This strain builds up in 10 ps and relaxes in 50 ps as the protein evolves towards its deoxy form.

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