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N. N. Ugarova, G. Yu. Lomakina
The emitter as an intramolecular probe in
the luciferase active center
Abstract
The distinctive features of firefly
luciferase bioluminescence are the complex changes of the spectrum form and λmax of bioluminescence under variation
of pH, temperature, and enzyme structure. Analysis of the literature data and
the own results of the authors leads to the conclusion that the keto-enol
tautomerism of oxyluciferin molecule explains the mostauthentically
observable complex spectral changes. Only one molecule of electronically exited
product is formed in the active site of each luciferase molecule. Hence, the
emitter can be considered as the intramolecular probe, characterizing the
properties of its microenvironment in the active center of the enzyme.
Superposition of two or three forms of the emitter recorded in bioluminescence
spectra indicates that various conformational forms of enzyme co-exist in the
reaction medium, that are in a dynamic equilibrium. The analysis of the
bioluminescence spectra permits to identify qualitatively and quontitatively
the differentenzyme conformers and their variations depending external
conditions and the luciferase structure.
Key words: bioluminescence, firefly
luciferase, keto-enol tautomerization, oxyluciferin.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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