The Experts below are selected from a list of 12513 Experts worldwide ranked by ideXlab platform

Toshiyuki Kohno - One of the best experts on this subject based on the ideXlab platform.

  • A novel way of amino acid-specific assignment in (1)H-(15)N HSQC spectra with a wheat germ cell-free protein synthesis system.
    Journal of Biomolecular NMR, 2004
    Co-Authors: Eugene Hayato Morita, Rikou Tanaka, Yaeta Endo, Masato Shimizu, Tomio Ogasawara, Toshiyuki Kohno
    Abstract:

    For high-throughput protein structural analyses, it is indispensable to develop a reliable protein overexpression system. Although many protein overexpression systems, such as ones utilizing E. coli cells, have been developed, a lot of proteins functioning in solution still were synthesized as insoluble forms. Recently, a novel wheat germ cell-free protein synthesis system was developed, and many of such proteins were synthesized as soluble forms. This means that the applicability of this protein synthesis method to determination of the functional structures of soluble proteins. In our previous work, we synthesized 15N-labeled proteins with this wheat germ cell-free system, and confirmed this applicability on the basis of the strong similarity between the 1H-15N HSQC spectra for native proteins and the corresponding ones for synthesized ones.

  • A wheat germ cell-free system is a novel way to screen protein folding and function
    Protein Science, 2003
    Co-Authors: Eugene Hayato Morita, Tatsuya Sawasaki, Rikou Tanaka, Yaeta Endo, Toshiyuki Kohno
    Abstract:

    For high-throughput protein structural analysis, it is indispensable to develop a reliable protein overexpression system. Although many protein overexpression systems, such as that involving Escherichia coli cells, have been developed, the number of overexpressed proteins showing the same biological activities as those of the native proteins is limited. A novel wheat germ cell-free protein synthesis system was developed recently, and most of the proteins functioning in solution were synthesized as soluble forms. This suggests the applicability of this protein synthesis method to determination of the solution structures of functional proteins. To examine this possibility, we have synthesized two 15N-labeled proteins and obtained 1H-15N HSQC spectra for them. The structural analysis of these proteins has already progressed with an E. coli overexpression system, and 1H-15N HSQC spectra for biologically active proteins have already been obtained. Comparing the spectra, we have shown that proteins synthesized with a wheat germ cell-free system have the proper protein folding and enough biological activity. This is the first experimental evidence of the applicability of the wheat germ cell-free protein synthesis system to high-throughput protein structural analysis.

C. Griesinger - One of the best experts on this subject based on the ideXlab platform.

  • Determination of ^3J(H _infi ^supN ,C _infi ^sup′ ) coupling constants in proteins with the C′-FIDS method
    Journal of Biomolecular NMR, 1995
    Co-Authors: A. Rexroth, S. Szalma, R. Weisemann, W. Bermel, H. Schwalbe, C. Griesinger
    Abstract:

    We introduce the C′-FIDS-^1H,^15N-HSQC experiment, a new method for the determination of ^3J(H _infi ^supN ,C _infi ^sup′ ) coupling constants in proteins, yielding information about the torsional angle ϕ. It relies on the ^1H,^15N-HSQC or HNCO experiment, two of the the most sensitive heteronuclear correlation experiments for isotopically labeled proteins. A set of three ^1H,^15N-HSQC or HNCO spectra are recorded: a reference experiment in which the carbonyl spins are decoupled during t_1 and t_2, a second experiment in which they are decoupled exclusively during t_1 and a third one in which they are coupled in t_1 as well as t_2. The last experiment yields an E.COSY-type pattern from which the ^2J(H _infi ^supN ,C _infi-1 ^sup′ ) and ^1J(N_i,C _infi-1 ^sup′ ) coupling constants can be extracted. By comparison of the coupled multiplet (obtained from the second experiment) with the decoupled multiplet (obtained from the first experiment) convoluted with the ^2J(H _infi ^supN ,C _infi-1 ^sup′ ) coupling, the ^3J(H _infi ^supN ,C _infi ^sup′ ) coupling can be found in a one-parameter fitting procedure. The method is demonstrated for the protein rhodniin, containing 103 amino acids. Systematic errors due to differential relaxation are small for ^nJ(H^N,C′) couplings in biomacromolecules of the size currently under NMR spectroscopic investigation.

  • Determination of (3)J(H (infi) (supN) ,C (infi) (sup') ) coupling constants in proteins with the C'-FIDS method.
    Journal of Biomolecular NMR, 1995
    Co-Authors: A. Rexroth, S. Szalma, R. Weisemann, W. Bermel, H. Schwalbe, C. Griesinger
    Abstract:

    We introduce the C′-FIDS-1H,15N-HSQC experiment, a new method for the determination of 3J(H infi supN ,C infi sup′ ) coupling constants in proteins, yielding information about the torsional angle ϕ. It relies on the 1H,15N-HSQC or HNCO experiment, two of the the most sensitive heteronuclear correlation experiments for isotopically labeled proteins. A set of three 1H,15N-HSQC or HNCO spectra are recorded: a reference experiment in which the carbonyl spins are decoupled during t1 and t2, a second experiment in which they are decoupled exclusively during t1 and a third one in which they are coupled in t1 as well as t2. The last experiment yields an E.COSY-type pattern from which the 2J(H infi supN ,C infi-1 sup′ ) and 1J(Ni,C infi-1 sup′ ) coupling constants can be extracted. By comparison of the coupled multiplet (obtained from the second experiment) with the decoupled multiplet (obtained from the first experiment) convoluted with the 2J(H infi supN ,C infi-1 sup′ ) coupling, the 3J(H infi supN ,C infi sup′ ) coupling can be found in a one-parameter fitting procedure. The method is demonstrated for the protein rhodniin, containing 103 amino acids. Systematic errors due to differential relaxation are small for nJ(HN,C′) couplings in biomacromolecules of the size currently under NMR spectroscopic investigation.

David S Libich - One of the best experts on this subject based on the ideXlab platform.

Eugene Hayato Morita - One of the best experts on this subject based on the ideXlab platform.

  • A novel way of amino acid-specific assignment in (1)H-(15)N HSQC spectra with a wheat germ cell-free protein synthesis system.
    Journal of Biomolecular NMR, 2004
    Co-Authors: Eugene Hayato Morita, Rikou Tanaka, Yaeta Endo, Masato Shimizu, Tomio Ogasawara, Toshiyuki Kohno
    Abstract:

    For high-throughput protein structural analyses, it is indispensable to develop a reliable protein overexpression system. Although many protein overexpression systems, such as ones utilizing E. coli cells, have been developed, a lot of proteins functioning in solution still were synthesized as insoluble forms. Recently, a novel wheat germ cell-free protein synthesis system was developed, and many of such proteins were synthesized as soluble forms. This means that the applicability of this protein synthesis method to determination of the functional structures of soluble proteins. In our previous work, we synthesized 15N-labeled proteins with this wheat germ cell-free system, and confirmed this applicability on the basis of the strong similarity between the 1H-15N HSQC spectra for native proteins and the corresponding ones for synthesized ones.

  • A wheat germ cell-free system is a novel way to screen protein folding and function
    Protein Science, 2003
    Co-Authors: Eugene Hayato Morita, Tatsuya Sawasaki, Rikou Tanaka, Yaeta Endo, Toshiyuki Kohno
    Abstract:

    For high-throughput protein structural analysis, it is indispensable to develop a reliable protein overexpression system. Although many protein overexpression systems, such as that involving Escherichia coli cells, have been developed, the number of overexpressed proteins showing the same biological activities as those of the native proteins is limited. A novel wheat germ cell-free protein synthesis system was developed recently, and most of the proteins functioning in solution were synthesized as soluble forms. This suggests the applicability of this protein synthesis method to determination of the solution structures of functional proteins. To examine this possibility, we have synthesized two 15N-labeled proteins and obtained 1H-15N HSQC spectra for them. The structural analysis of these proteins has already progressed with an E. coli overexpression system, and 1H-15N HSQC spectra for biologically active proteins have already been obtained. Comparing the spectra, we have shown that proteins synthesized with a wheat germ cell-free system have the proper protein folding and enough biological activity. This is the first experimental evidence of the applicability of the wheat germ cell-free protein synthesis system to high-throughput protein structural analysis.

Inna Freikman - One of the best experts on this subject based on the ideXlab platform.

  • The trans labilization of cis-[PtCl_2(^13CH_3NH_2)_2] by glutathione can be monitored at physiological pH by [1H,13C] HSQC NMR
    JBIC Journal of Biological Inorganic Chemistry, 2006
    Co-Authors: Dan Gibson, Yonit Kasherman, Dina Kowarski, Inna Freikman
    Abstract:

    In order to monitor the trans labilization of cisplatin at physiological pH we have prepared the complex cis -[PtCl_2(^13CH_3NH_2)_2] and studied its interactions with excess glutathione in aqueous solution at neutral pH by two-dimensional [1H,13C] heteronuclear single-quantum correlation (HSQC) NMR spectroscopy. [1H,13C] HSQC spectroscopy is a good method for following the release of ^13CH_3NH_2 but is not so good for characterizing the Pt species in solution. In the reaction of cisplatin with glutathione, Pt–S bonds are formed and Pt–NH_3 bonds are broken. The best technique for following the formation of Pt–S bonds of cisplatin is by UV spectroscopy. [1H,13C] HSQC spectroscopy is the best method for following the breaking of the Pt–N bonds. [1H,15N] HSQC spectroscopy is the best method for characterizing the different species in solution. However, the intensity of the peaks in the ^15NH_3–Pt–S region, in [1H,15N] HSQC, reflects a balance between the formation of Pt–S bonds, which increases the signal intensity, and the trans labilization, which decreases the signal intensity. [1H,15N] HSQC spectroscopy and [1H,13C] HSQC spectroscopy are complementary techniques that should be used in conjunction in order to obtain the most accurate information on the interaction of platinum complexes with sulfur-containing ligands.

  • The trans labilization of cis-[PtCl2(13CH3NH2)2] by glutathione can be monitored at physiological pH by [1H,13C] HSQC NMR.
    Journal of Biological Inorganic Chemistry, 2005
    Co-Authors: Dan Gibson, Yonit Kasherman, Dina Kowarski, Inna Freikman
    Abstract:

    In order to monitor the trans labilization of cisplatin at physiological pH we have prepared the complex cis-[PtCl2(13CH3NH2)2] and studied its interactions with excess glutathione in aqueous solution at neutral pH by two-dimensional [1H,13C] heteronuclear single-quantum correlation (HSQC) NMR spectroscopy. [1H,13C] HSQC spectroscopy is a good method for following the release of 13CH3NH2 but is not so good for characterizing the Pt species in solution. In the reaction of cisplatin with glutathione, Pt–S bonds are formed and Pt–NH3 bonds are broken. The best technique for following the formation of Pt–S bonds of cisplatin is by UV spectroscopy. [1H,13C] HSQC spectroscopy is the best method for following the breaking of the Pt–N bonds. [1H,15N] HSQC spectroscopy is the best method for characterizing the different species in solution. However, the intensity of the peaks in the 15NH3–Pt–S region, in [1H,15N] HSQC, reflects a balance between the formation of Pt–S bonds, which increases the signal intensity, and the trans labilization, which decreases the signal intensity. [1H,15N] HSQC spectroscopy and [1H,13C] HSQC spectroscopy are complementary techniques that should be used in conjunction in order to obtain the most accurate information on the interaction of platinum complexes with sulfur-containing ligands.