Electricity: measuring and testing – Particle precession resonance – Spectrometer components
Reexamination Certificate
1999-10-27
2002-03-26
Arana, Louis (Department: 2862)
Electricity: measuring and testing
Particle precession resonance
Spectrometer components
C324S300000
Reexamination Certificate
active
06362624
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of NMR spectroscopy. More particularly, the present invention provides an apparatus and method for high resolution Nuclear Magnetic Resonance (NMR) spectroscopy. This method is particularly useful for determining molecular structure and dynamics in materials such as proteins and protein complexes.
DESCRIPTION OF RELATED ART
The origin of local and global stability and dynamics of proteins and protein complexes have long been of interest and are now of particular importance in the emerging field of protein design and engineering. One approach to the determination of molecular structure and dynamics in proteins involves the use of high pressure NMR spectroscopy. The use of pressure to probe the global and local stabilities of proteins and protein complexes apparently offers the opportunity to selectively destabilize certain classes of interactions with respect to others based on significant differences in the standard free energies and volume changes associated with their disruption. For example, protein complexes that are stabilized by intermolecular salt links are often exquisitely sensitive to pressure and dissociate at pressures of a few hundred bar (Silva et al., 1993,
Ann. Rev. Phys. Chem.
44:489-113); Weber et al., 1983,
Quaterly Rev. Biophys.
1689-112; Robinson et al., 1995,
Meth. Enz.
259:395-427).
Since the pioneering work of Benedek and Purcell (1954,
J. Chem. Phy.
22:2003-2012) two types of approaches to achieving high pressure NMR capability have evolved. The high pressure probe technique takes the design principle that the entire RF coil and sample are to be pressurized. The original design strategy has been adopted and extended by Jonas and coworkers (Jonas and Jonas, 1994,
Ann. Rev. Biophys. Biomol. Struct.,
23:287-318; Jonas et al, 1993,
Magn. Reson., Series B,
102:229-309). The second general approach is the high pressure cell technique which employs thick walled glass (Wagner, 1980,
FEBS Lett.,
112:280-284), Vespel (Vanni et al., 1978,
J. Magn. Reson.,
29:11-19) or sapphire (Roe, 1985,
J. Magn. Reson.,
63:388-391) tubes of various construction or reinforced quartz capillaries (Yamada, 1974,
Rev. Sci. Instrum.,
45:640-642) which fit directly into a standard NMR probehead.
Previously, others have disclosed pressure cells for use in NMR measurements. U.S. Pat. No. 5,045,793 to Rathke describes the design and use of a high pressure probe with emphasis on the RF coil design. The whole probe was pressurized in order to make the measurements. An operating pressure of 4750 psi (327.5 bar) for 12 hours was used. U.S. Pat. No. 5,122,745 to Smith et al., describes a method and apparatus for determining molecular dynamics of materials. The apparatus entails a high pressure cell where pressures of up to 50 atmospheres (50.7 bar) were achieved. The high pressure cell is combined with an NMR probe to analyze samples. Other reports in the literature, where high pressure was approached, illustrate use of only simple homonuclear NMR spectroscopy at pressures above 1 kilobar (see Jonas and Jonas 1994, supra).
A sapphire tube was used by Roe (1985, supra) to achieve high pressures. The sample tube was mounted to a titanium alloy flange with a single component epoxy adhesive. Pressures of 5000 psi (345 bar) were routinely used. The sapphire tube burst at a pressure of 14,500 psi (1 kilobar).
Thus, while it is of great interest to apply techniques such as NMR spectroscopy to the analysis of pressure-induced transitions in protein complexes, it has not been possible heretofore to subject samples to kilobar pressures. Therefore, there is a need for a pressure cell that can withstand high pressures while allowing state-of-the-art NMR measurements.
REFERENCES:
patent: 4164700 (1979-08-01), Christoe et al.
patent: 5045793 (1991-09-01), Rathke
patent: 5122745 (1992-06-01), Smith
patent: 5258712 (1993-11-01), Hofmann et al.
patent: 5517856 (1996-05-01), Hofmann et al.
Wagner, “Activation Volumes for the Rotational Motion of Interior Aromatic Rings in Globular Proteins Determined by High Resolution1HNMR at Variable Pessure”, FEBS Letters, Apr. 1980, vol. 112, No. 2, pp. 280-284.
Vannie et al., “Two Approaches to High-Resolution High-Pressure Nuclear Magnetic Resonance”, Journal of Magnetic Resonance, 1978, vol. 29, pp. 11-19.
Yamada, “Pressure-resisting glass cell for high pressure, high resolution NMR measurement”, Rev. Sci. Instrum., May 1974, vol. 45, No. 5, pp. 640-643.
Roe, “Sapphire NMR Tube for High Resolution Studies at Elevated Pressure”, Journal of Magnetic Resonance, 1985, vol. 63, pp. 388-391.
Jonas et al., “High-Pressure NMR Spectroscopy of Proteins and Membranes”, Ann. Rev. Biophys. Biomol. Struct., 1994, vol. 23, pp. 287-318.
Jouanne, “High Resolution NMR Under Increased Hyudrostatic Pressure: Keto-Enol Equilibrium of Acetylacetone,” Journal of Magnetic Resonace 7, vol. 1, 1972, pp. 1-4.
Ehrhardt Mark R.
Urbauer Jeffrey L.
Wand Andrew J.
Arana Louis
Hodgson & Russ LLP
The Research Foundation of State University of New York
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