Domain structure of Escherichia coli DNA gyrase as revealed by differential scanning calorimetry.
The domain structure of DNA gyrase from Escherichia coli has been examined using differential scanning microcalorimetry. The intact enzyme (an A2B2 tetramer) shows at least four transitions with apparent Tm's at 44.8, 53.3, 58.6, and 60.7 degrees C. Comparison with the thermal stabilities of the two separate subunits and genetically-engineered protein fragments has been used to assign these transitions to individual domains within the intact gyrase proteins. The thermal unfolding of DNA gyrase and all individual fragments are irreversible under the conditions of the calorimetric experiment. Further evidence for the assignment of transitions to particular domains has been obtained by studying the effects of tight-binding ligands such as novobiocin on the thermal stabilities of the various protein fragments.
Blandamer
M J
MJ
Department of Chemistry, Leicester University, U.K.
Briggs
B
B
Cullis
P M
PM
Jackson
A P
AP
Maxwell
A
A
Reece
R J
RJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D002152:Calorimetry, Differential Scanning; D004247:DNA / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000737:chemistry*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology*; D006358:Hot Temperature; D046911:Macromolecular Substances; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D011489:Protein Denaturation; D017510:Protein Folding; D012984:Software; D013816:Thermodynamics
D046911:Macromolecular Substances; D010446:Peptide Fragments; D000255:Adenosine Triphosphate; D004247:DNA; D004250:DNA Topoisomerases, Type II