Protein response to ligation reactions in myoglobin
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 areinvestigated, from ultrafast phenomena (picoseconds) to relatively slow processes (milliseconds). Conformational changes in myoglobin (Mb) are detected by time-resolved 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[sup [minus]1] . The time course ofchanges 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 n. 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.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- DOE; DOHHS; USDOE, Washington, DC (United States); Department of Health and Human Services, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6708071
- Report Number(s):
- LA-UR-92-572; CONF-930159--18; ON: DE93008700; CNN: GM48509; X15B
- Country of Publication:
- United States
- Language:
- English
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Picosecond structural dynamics of myoglobin following photolysis of carbon monoxide
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59 BASIC BIOLOGICAL SCIENCES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CONFORMATIONAL CHANGES
DECOMPOSITION
ELECTROMAGNETIC RADIATION
GLOBINS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFRARED RADIATION
INFRARED SPECTRA
LASER SPECTROSCOPY
MYOGLOBIN
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PIGMENTS
PORPHYRINS
PROTEINS
RADIATIONS
SPECTRA
SPECTROSCOPY