Near infrared transient absorption spectra of photolyzed myoglobin at low temperatures

"We have measured the transient absorption spectrum of photolyzed sperm whale carboxymyoglobin as a function of temperature and time after photolysis. Our measurements extend from 60K to 220K and from three microseconds to thirty seconds. We see an absorption band near 758 nm which is known as band VIII. Three microseconds after photolysis at 60K, the center of band VIII is 766 nm, red-shifted from the peak seen in deoxy myoglobin at this temperature. Band VIII shifts with time towards the deoxy value with a nonexponential time course. We conclude that this shift is caused by unrelaxed degrees of freedom in the protein at these temperatures. We present a model in which each protein has several ""blocking residues"" which relax following photolysis by surmounting enthalpy barriers which range from ten to fifty kJ/mol. These motions do not affect the rate of ligand rebinding."

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Bowne, Samuel Franklin

Contributors dc:contributor

• Frauenfelder, Hans

• transient absorption spectrum
• photolyzed carboxymyoglobin
• band shifts

Statement dc:rights

• 1984 Samuel Franklin Bowne

Language dc:language

en

Identifier

824272

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25311