High pressure nmr study of dihydrofolate reductase from a deep-sea bacterium Moritella profunda
Hata, K.; Kono, R.; Fujisawa, M.; Kitahara, R.; Kamatari, Y.O.; Akasaka, K.; Xu, Y.
Cellular and Molecular Biology 50(4): 311-316
2004
ISSN/ISBN: 0145-5680 PMID: 15529739 Document Number: 583294
We have investigated the effect of pressure and temperature on the structural and thermodynamic stability of a protein dihydrofolate reductase from a deep-sea bacterium Moritella profunda in its folate-bound form in the pressure range between 3 and 375 MPa and the temperature range between -5 and 30degreeC. The on-line cell variable pressure 1H NMR spectroscopy has been used to analyze the chemical shift and signal intensity in one-dimensional 1H NMR spectra. Thermodynamic analysis based on signal intensities from protons in the core part indicates that the thermodynamic stability of Moritella profunda DHFR is relatively low over the temperature range between -5 and 30degreeC (triangleG0= 15.8 +/- 4.1 kJ/mol at 15degreeC), but is well adapted to the living environment of the bacterium (2degreeC and 28 MPa), with the maximum stability around 5degreeC (at 0.1 MPa) and a relatively small volume change upon unfolding (triangleV= -66 +/- 19 ml/mol). Despite the relatively low overall stability, the conformation in the core part of the folded protein remains intact up to apprx200 MPa, showing marked stability of the core of this protein.