Abstract
The picosecond evolution of the tertiary conformation of myoglobin (Mb) after photodissociation of MbCO was investigated at room temperature by probing band III, a weak iron-porphyrin charge-transfer transition near 13,110 cm-1 (763 nm) that is sensitive to the out-of-plane displacement of the iron. Upon photolysis, the iron moves out of the plane of the porphyrin, causing a blue-shift of band III and a concomitant change in the protein conformation. The dynamics for this functionally important motion are highly nonexponential, in agreement with recent molecular dynamics simulations [Kuczera, K., Lambry, J.-C., Martin, J.-L. & Karplus, M. (1993) Proc. Natl. Acad. Sci. USA 90, 5805-5807]. The conformational change likely affects the height of the barrier to ligand rebinding and may explain nonexponential NO rebinding.
Original language | English (US) |
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Pages (from-to) | 5801-5804 |
Number of pages | 4 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 90 |
Issue number | 12 |
State | Published - Jun 15 1993 |
Externally published | Yes |
Keywords
- band III(763 nm)
- functionally important motion
- photodissociation of MbCO
- time-resolved absorption spectroscopy
ASJC Scopus subject areas
- General