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The studies of cooperative regions in T7 RNA polymerase
Author(s) -
Protasevich I.I.,
Memelova L.V.,
Kochetkov S.N.,
Makarov A.A.
Publication year - 1994
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(94)00718-7
Subject(s) - thermostability , isothermal microcalorimetry , denaturation (fissile materials) , rna polymerase , molecule , chemistry , bacteriophage , crystallography , molecular mass , rna , polymerase , biophysics , biochemistry , biology , thermodynamics , enthalpy , enzyme , organic chemistry , nuclear chemistry , physics , escherichia coli , gene
The heat denaturation of bacteriophage T7 RNA polymerase (T7RNAP) was studied by scanning microcalorimetry. The thermodynamic parameters of the denaturation were estimated within the pH range 6–9. The analysis of the denaturation curves showed the presence of two cooperative parts of the T7RNAP molecule melting according to the ‘all‐or‐none’ principle. The molecular masses of these parts were determined as 22 and 77 kDa. These values are close to the molecular masses of protein domains obtained from X‐ray diffraction and limited trypsinolysis data. The smaller N‐terminal domain was shown to increase the thermostability of the ‘catalytic’ C‐terminal domain within the intact T7RNAP molecule.