A tradeoff between protein stability and conformational mobility in homotrimeric dUTPases.
Oligomerization directs active site formation in homotrimeric 2'-deoxyuridine triphosphate pyrophosphatases (dUTPases). Stability of the homotrimer is a central determinant in enzyme function. The present comparative studies of bacterial and fruitfly dUTPases with homologous 3D structures by differential scanning microcalorimetry; fluorescence, circular dichorism and infrared spectroscopies, demonstrate that unfolding is a two-state highly cooperative transition in both dUTPases excluding a significantly populated intermediate state of dissociated and folded monomers. The eukaryotic protein is much less resistant against either thermal or guanidine hydrochloride-induced denaturation. Results suggest that hydrophobic packing of the inner threefold channel of the dUTPase homotrimer greatly contributes to stability.
Takács
Eniko
E
Institute of Enzymology, Hungarian Academy of Sciences, POB 7, H-1518, Budapest, Hungary.
Grolmusz
Vince K
VK
Vértessy
Beáta G
BG
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D029721:Drosophila Proteins / Q000737:chemistry; D004331:Drosophila melanogaster / Q000201:enzymology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology; D019791:Guanidine / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D011755:Pyrophosphatases / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D001426:Bacterial Proteins; D029721:Drosophila Proteins; D008024:Ligands; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase; D019791:Guanidine