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Characterization of the dimerization process of HIV‐1 reverse transcriptase heterodimer using intrinsic protein fluorescence
Author(s) -
Divita G.,
Restle T.,
Goody R.S.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81383-b
Subject(s) - reverse transcriptase , fluorescence , human immunodeficiency virus (hiv) , chemistry , characterization (materials science) , biophysics , virology , biochemistry , biology , rna , nanotechnology , materials science , gene , physics , quantum mechanics
Intrinsic protein fluorescence has been used to study dimerization of the HIV‐1 reverse transcriptase (RT). We observed a 25% increase of the tryptophan fluorescence of the enzyme during dissociation of the subunits induced by the addition of acetonitrile. Upon reassociation of the separated subunits, the original fluorescence emission of the heterodimer is restored. A two‐state transition model for the RT dimerization process in which the dimers are in equilibrium with folded monomers is proposed. The free energy of dissociation was determined to be 12.2 (± 0.2) kcal/mol. In the absence of Mg 2+ ions a decrease of this value was observed, whereas the addition of a synthetic primer/template (18/36mer) results in an increase of dimer stability. Analyzing the effect of Mg 2+ on the establishment of the binding equilibrium, a dramatic effect with a 100‐fold acceleration of the association by the divalent ion was observed.