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Proceedings Paper

Protein response to ligation reactions in myoglobin
Author(s): Timothy P. Causgrove; R. Brian Dyer
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Paper Abstract

The protein response to the photodissociation, escape and subsequent rebinding of carbon monoxide in myoglobin is studied using time-resolved infrared (TRIR) spectroscopy. All phases of these reactions are investigated, from ultrafast phenomena (picoseconds) to relatively slow processes (milliseconds). Conformational changes in myoglobin (Mb) are detected by time-resolved infrared absorption changes in the amide I band. On the hundreds of nanoseconds to milliseconds timescale, a 'real-time' apparatus is used. This apparatus is based on a tunable diode laser operating in the region of 1650 cm-1. The time course of changes in the amide I band are shown to follow the recombination of CO with photolyzed Mb. On the basis of the rise times of the amide I and Fe-CO signals, it is concluded that protein motion is complete within 100 ns. A time-resolved difference spectrum in the amide I region is generated from single wavelength transients taken throughout the amide I envelope. A static difference spectrum is also generated by subtracting FTIR spectra of carbonmonoxy and deoxy myoglobin. The two difference spectra are compared and are interpreted in terms of the three-dimensional structures of deoxy and carbonmonoxy Mb. Preliminary picosecond TRIR data are also given for the ultrafast response of the protein immediately following photodissociation of CO.

Paper Details

Date Published: 1 May 1993
PDF: 9 pages
Proc. SPIE 1890, Biomolecular Spectroscopy III, (1 May 1993); doi: 10.1117/12.145243
Show Author Affiliations
Timothy P. Causgrove, Los Alamos National Lab. (United States)
R. Brian Dyer, Los Alamos National Lab. (United States)

Published in SPIE Proceedings Vol. 1890:
Biomolecular Spectroscopy III
Laurence A. Nafie; Henry H. Mantsch, Editor(s)

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