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Water Release upon DNA Binding by E. coli and T. aquaticus Pol I DNA Polymerases
Author(s) -
Baker John T.,
Deredge Daniel J.,
Datta Kausiki,
LiCata Vince J.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.482.6
Subject(s) - klenow fragment , dna polymerase , chemistry , biophysics , dna , dna polymerase i , polymerase , dna clamp , osmolyte , biochemistry , biology , polymerase chain reaction , reverse transcriptase , gene , exonuclease
Klentaq ( T. aquaticus ) and Klenow ( E. coli) are a thermophilic‐mesophilic pair of Type I DNA polymerases with similar morphologies. The thermodynamic linkage between binding affinity and the osmotic pressure induced by non‐interacting osmolytes can be used to calculate the number of water molecules bound or released during a macromolecular process such as DNA binding. Approximately 600 water molecules are released when Klentaq polymerase binds to either primed‐template or blunt‐end DNA. In contrast, only approximately 500 waters are released when Klenow binds primed‐template DNA, however, the necessity of measuring Klenow DNA binding at significantly higher salt concentrations may be the source of this difference. For both proteins, the measured water release is significantly higher than that predicted from the burial of surface area upon complex formation calculated from structural data (approximately 300 waters). Steric displacement of non‐surface associated water within the DNA binding cleft of the proteins may account for this difference, and indicates that these binding reactions will be more enhanced at intracellular osmotic pressures than would be predicted from surface area calculations.