Circular Dichroism Studies on the Deinococcus radiodurans Nudix Hydrolase DR_0079: An Atypical Thermal Melt

Author(s): Garry W. Buchko.

Journal Name: Protein & Peptide Letters

Volume 17 , Issue 7 , 2010

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Abstract:

The crystal structure for the Deinococcus radiodurans Nudix protein DR_0079 was recently determined in the metal-free form at 1.9 Å resolution (2O5F). The protein adopts the fundamental fold common to the Nudix family of proteins, a large mixed β-sheet sandwiched between the α-helix of the “Nudix box” and a second α-helix. The proteins physical properties were further characterized by circular dichroism (CD) spectroscopy. A CD thermal melt at 220 nm indentifies an inflection point at ∼52°C. However, unlike typical CD thermal melts, the negative ellipticity at 220 nm becomes more negative upon passing through the inflection point. Both NMR spectroscopy and size exclusion chromatography indicate that heating effects the irreversible formation of a large molecular weight complex. After cooling, the negative ellipiticity at 220 nm increases further, and overall, the CD spectrum at 25°C suggests that heat-treated DR_0079 has more α-helical and β-sheet structure than non-heat treated DR_0079.

Keywords: Circular dichroism spectroscopy, NMR spectroscopy, Nudix hydrolase, polyphosphate pyrophosphohydrolase, protein aggregation, protein refolding, thermal stability

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Article Details

VOLUME: 17
ISSUE: 7
Year: 2010
Page: [831 - 835]
Pages: 5
DOI: 10.2174/092986610791306689
Price: $65

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