The homodimeric HU protein from the hyperthermophile Thermotoga maritima (HUTmar) is a model system which can yield insights into the molecular determinants of thermostability in proteins. Unusually for a thermostable protein, HUTmar exists in a structurally heterogeneous state as evidenced by the assignment of two distinct and approximately equally populated forms in solution. Relaxation measurements combined with chemical shift, hydrogen exchange, and nuclear Overhauser enhancement data confirm the main structural features of both forms. In addition, these data support a two-state model for HUTmar in which the major form closely resembles the X-ray structure while the very flexible minor form is less structured. HUTmar may therefore be a new example of the small class of hyperthermostable proteins with unexpected flexibility.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Apr 9 2004|
Bibliographical noteFunding Information:
The NMR spectra were recorded at the SON NMR Large Scale Facility in Utrecht, which is funded by the Access to Research Infrastructures programme of the European Union (HPRI-CT-2001-00172). We thank Klaartje Houben for setting up the relaxation experiments and analysis scripts and Hans Wienk for reading the manuscript. This work was supported by a Marie Curie training site fellowship (HPMT-2000-00045) awarded to M.A.D.
- Conformational flexibility
- HUBst, Bacillus stearothermophilus HU protein
- HUBsu, Bacillus subtilis HU protein
- HUTmar, Thermotoga maritima HU protein
- Nuclear magnetic resonance spin relaxation
- Protein dynamics