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Robertson AJ, Ying J, Bax A. NMR Observation of Sulfhydryl Signals in SARS-CoV-2 Main Protease Aids Structural Studies. Chembiochem 2022; 23:e202200471. [PMID: 35972230 PMCID: PMC9537880 DOI: 10.1002/cbic.202200471] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 08/15/2022] [Indexed: 11/24/2022]
Abstract
The 68‐kDa homodimeric 3C‐like protease of SARS‐CoV‐2, Mpro (3CLpro/Nsp5), is a key antiviral drug target. NMR spectroscopy of this large system proved challenging and resonance assignments have remained incomplete. Here we present the near‐complete (>97 %) backbone assignments of a C145A variant of Mpro (MproC145A) both with, and without, the N‐terminal auto‐cleavage substrate sequence, in its native homodimeric state. We also present SILLY (Selective Inversion of thioL and Ligand for NOESY), a simple yet effective pseudo‐3D NMR experiment that utilizes NOEs to identify interactions between Cys‐thiol or aliphatic protons, and their spatially proximate backbone amides in a perdeuterated protein background. High protection against hydrogen exchange is observed for 10 of the 11 thiol groups in MproC145A, even those that are partially accessible to solvent. A combination of SILLY methods and high‐resolution triple‐resonance NMR experiments reveals site‐specific interactions between Mpro, its substrate peptides, and other ligands, which present opportunities for competitive binding studies in future drug design efforts.
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Affiliation(s)
- Angus J Robertson
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Chemical Physics, UNITED STATES
| | - Jinfa Ying
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Chemical Physics, UNITED STATES
| | - Ad Bax
- Nat. Inst. Diabetes, Laboratory Chem. Phys., Building 5, Rm 126, 20892, Bethesda, UNITED STATES
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2
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A Novel Glutathione S-Transferase Gtt2 Class (VpGSTT2) Is Found in the Genome of the AHPND/EMS Vibrio parahaemolyticus Shrimp Pathogen. Toxins (Basel) 2021; 13:toxins13090664. [PMID: 34564668 PMCID: PMC8472993 DOI: 10.3390/toxins13090664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 11/26/2022] Open
Abstract
Glutathione S-transferases are a family of detoxifying enzymes that catalyze the conjugation of reduced glutathione (GSH) with different xenobiotic compounds using either Ser, Tyr, or Cys as a primary catalytic residue. We identified a novel GST in the genome of the shrimp pathogen V. parahaemolyticus FIM- S1708+, a bacterial strain associated with Acute Hepatopancreatic Necrosis Disease (AHPND)/Early Mortality Syndrome (EMS) in cultured shrimp. This new GST class was named Gtt2. It has an atypical catalytic mechanism in which a water molecule instead of Ser, Tyr, or Cys activates the sulfhydryl group of GSH. The biochemical properties of Gtt2 from Vibrio parahaemolyticus (VpGSTT2) were characterized using kinetic and crystallographic methods. Recombinant VpGSTT2 was enzymatically active using GSH and CDNB as substrates, with a specific activity of 5.7 units/mg. Low affinity for substrates was demonstrated using both Michaelis–Menten kinetics and isothermal titration calorimetry. The crystal structure showed a canonical two-domain structure comprising a glutathione binding G-domain and a hydrophobic ligand H domain. A water molecule was hydrogen-bonded to residues Thr9 and Ser 11, as reported for the yeast Gtt2, suggesting a primary role in the reaction. Molecular docking showed that GSH could bind at the G-site in the vicinity of Ser11. G-site mutationsT9A and S11A were analyzed. S11A retained 30% activity, while T9A/S11A showed no detectable activity. VpGSTT2 was the first bacterial Gtt2 characterized, in which residues Ser11 and Thr9 coordinated a water molecule as part of a catalytic mechanism that was characteristic of yeast GTT2. The GTT2 family has been shown to provide protection against metal toxicity; in some cases, excess heavy metals appear in shrimp ponds presenting AHPND/EMS. Further studies may address whether GTT2 in V. parahaemolyticus pathogenic strains may provide a competitive advantage as a novel detoxification mechanism.
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3
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Takeda M, Miyanoiri Y, Terauchi T, Kainosho M. Conformational features and ionization states of Lys side chains in a protein studied using the stereo-array isotope labeling (SAIL) method. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:223-237. [PMID: 37904773 PMCID: PMC10539808 DOI: 10.5194/mr-2-223-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/13/2021] [Indexed: 11/01/2023]
Abstract
Although both the hydrophobic aliphatic chain and hydrophilic ζ -amino group of the Lys side chain presumably contribute to the structures and functions of proteins, the dual nature of the Lys residue has not been fully investigated using NMR spectroscopy, due to the lack of appropriate methods to acquire comprehensive information on its long consecutive methylene chain. We describe herein a robust strategy to address the current situation, using various isotope-aided NMR technologies. The feasibility of our approach is demonstrated for the Δ + PHS/V66K variant of staphylococcal nuclease (SNase), which contains 21 Lys residues, including the engineered Lys-66 with an unusually low pK a of ∼ 5.6. All of the NMR signals for the 21 Lys residues were sequentially and stereospecifically assigned using the stereo-array isotope-labeled Lys (SAIL-Lys), [U-13 C,15 N; β 2 ,γ 2 ,δ 2 ,ε 3 -D4 ]-Lys. The complete set of assigned 1 H, 13 C, and 15 N NMR signals for the Lys side-chain moieties affords useful structural information. For example, the set includes the characteristic chemical shifts for the 13 Cδ , 13 Cε , and 15 Nζ signals for Lys-66, which has the deprotonated ζ -amino group, and the large upfield shifts for the 1 H and 13 C signals for the Lys-9, Lys-28, Lys-84, Lys-110, and Lys-133 side chains, which are indicative of nearby aromatic rings. The 13 Cε and 15 Nζ chemical shifts of the SNase variant selectively labeled with either [ε -13 C;ε ,ε -D2 ]-Lys or SAIL-Lys, dissolved in H2 O and D2 O, showed that the deuterium-induced shifts for Lys-66 were substantially different from those of the other 20 Lys residues. Namely, the deuterium-induced shifts of the 13 Cε and 15 Nζ signals depend on the ionization states of the ζ -amino group, i.e., - 0.32 ppm for Δ δ 13 Cε [Nζ D3 + -Nζ H3 + ] vs. - 0.21 ppm for Δ δ 13 Cε [Nζ D2 -Nζ H2 ] and - 1.1 ppm for Δ δ 15 Nζ [Nζ D3 + -Nζ H3 + ] vs. - 1.8 ppm for Δ δ 15 Nζ [Nζ D2 -Nζ H2 ]. Since the 1D 13 C NMR spectrum of a protein selectively labeled with [ε -13 C;ε ,ε -D2 ]-Lys shows narrow (> 2 Hz) and well-dispersed 13 C signals, the deuterium-induced shift difference of 0.11 ppm for the protonated and deprotonated ζ -amino groups, which corresponds to 16.5 Hz at a field strength of 14 T (150 MHz for 13 C), could be accurately measured. Although the isotope shift difference itself may not be absolutely decisive to distinguish the ionization state of the ζ -amino group, the 13 Cδ , 13 Cε , and 15 Nζ signals for a Lys residue with a deprotonated ζ -amino group are likely to exhibit distinctive chemical shifts as compared to the normal residues with protonated ζ -amino groups. Therefore, the isotope shifts would provide a useful auxiliary index for identifying Lys residues with deprotonated ζ -amino groups at physiological pH levels.
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Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, 5-1, Oe-honmachi, Chuo-ku, Kumamoto, 862-0973, Japan
| | - Yohei Miyanoiri
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Research Center for State-of-the-Art Functional Protein Analysis, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tsutomu Terauchi
- SAIL Technologies Co., Inc., 2008-2 Wada, Tama-city, Tokyo, 206-0001, Japan
- Graduate School of Science, Tokyo Metropolitan University, 1-1
Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Graduate School of Science, Tokyo Metropolitan University, 1-1
Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan
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4
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Isotope-Aided Methods for Biological NMR Spectroscopy: Past, Present, and Future. EXPERIMENTAL APPROACHES OF NMR SPECTROSCOPY 2018. [PMCID: PMC7122432 DOI: 10.1007/978-981-10-5966-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This chapter starts by providing a historical background of our research endeavors over the past half-century to develop various isotope-aided methods in biological NMR spectroscopy, since innovations bloom only on the rich ground cultivated by previous investigators. We then focused on the stereo-array isotope-labeling (SAIL) method, one of our recent accomplishments, which culminates the isotope-aided NMR technologies for structural studies of proteins from various aspects: accurate structural determinations of large proteins, elaboration for automated structural determination, highly efficient and versatile residue-selective methyl labeling with newly developed auxotrophic E. coli strains, large-amplitude slow-breathing motion (LASBM) as revealed by the aromatic ring flipping of the residues in ligand-binding interfaces, and applications of the deuterium-induced 13C-NMR isotope shift to investigate the hydrogen exchange phenomena of side-chain polar groups. Meanwhile, the expected role of NMR spectroscopy has been rapidly shifting from structure determinations to dynamics studies of biologically interesting targets, such as membrane proteins and larger protein complexes. The dynamic aspects of protein–protein and protein–ligand interactions are closely related to their biological functions and can be efficiently studied by using proteins residue selectively labeled with amino acids bearing optimized labeling patterns, prepared by cellular expression. We are absolutely confident that biological NMR spectroscopy will continually develop with further innovations of isotope-labeling technologies in the coming era, featuring ultrahigh field spectrometers beyond 1 GHz.
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Stable-Isotope-Aided NMR Spectroscopy. MODERN MAGNETIC RESONANCE 2018. [PMCID: PMC7123952 DOI: 10.1007/978-3-319-28388-3_48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Cao Z, Hutchison JM, Sanders CR, Bowie JU. Backbone Hydrogen Bond Strengths Can Vary Widely in Transmembrane Helices. J Am Chem Soc 2017; 139:10742-10749. [PMID: 28692798 PMCID: PMC5560243 DOI: 10.1021/jacs.7b04819] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
Although
backbone hydrogen bonds in transmembrane (TM) helices
have the potential to be very strong due to the low dielectric and
low water environment of the membrane, their strength has never been
assessed experimentally. Moreover, variations in hydrogen bond strength
might be necessary to facilitate the TM helix breaking and bending
that is often needed to satisfy functional imperatives. Here we employed
equilibrium hydrogen/deuterium fractionation factors to measure backbone
hydrogen bond strengths in the TM helix of the amyloid precursor protein
(APP). We find an enormous range of hydrogen bond free energies, with
some weaker than water–water hydrogen bonds and some over 6
kcal/mol stronger than water–water hydrogen bonds. We find
that weak hydrogen bonds are at or near preferred γ-secretase
cleavage sites, suggesting that the sequence of APP and possibly other
cleaved TM helices may be designed, in part, to make their backbones
accessible for cleavage. The finding that hydrogen bond strengths
in a TM helix can vary widely has implications for membrane protein
function, dynamics, evolution, and design.
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Affiliation(s)
- Zheng Cao
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
| | - James M Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
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7
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Takeda M, Miyanoiri Y, Terauchi T, Kainosho M. (13)C-NMR studies on disulfide bond isomerization in bovine pancreatic trypsin inhibitor (BPTI). JOURNAL OF BIOMOLECULAR NMR 2016; 66:37-53. [PMID: 27566173 DOI: 10.1007/s10858-016-0055-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
Conformational isomerization of disulfide bonds is associated with the dynamics and thus the functional aspects of proteins. However, our understanding of the isomerization is limited by experimental difficulties in probing it. We explored the disulfide conformational isomerization of the Cys14-Cys38 disulfide bond in bovine pancreatic trypsin inhibitor (BPTI), by performing an NMR line-shape analysis of its Cys carbon peaks. In this approach, 1D (13)C spectra were recorded at small temperature intervals for BPTI samples selectively labeled with site-specifically (13)C-enriched Cys, and the recorded peaks were displayed in the order of the temperature after the spectral scales were normalized to a carbon peak. Over the profile of the line-shape, exchange broadening that altered with temperature was manifested for the carbon peaks of Cys14 and Cys38. The Cys14-Cys38 disulfide bond reportedly exists in equilibrium between a high-populated (M) and two low-populated states (m c14 and m c38). Consistent with the three-site exchange model, biphasic exchange broadening arising from the two processes was observed for the peak of the Cys14 α-carbon. As the exchange broadening is maximized when the exchange rate equals the chemical shift difference in Hz between equilibrating sites, semi-quantitative information that was useful for establishing conditions for (13)C relaxation dispersion experiments was obtained through the carbon line-shape profile. With respect to the m c38 isomerization, the (1)H-(13)C signals at the β-position of the minor state were resolved from the major peaks and detected by exchange experiments at a low temperature.
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Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Structural BioImaging, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto, 862-0973, Japan
| | - Yohei Miyanoiri
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Tsutomu Terauchi
- Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan
- SAIL Technologies Inc., 2008-2 Wada, Tama, Tokyo, 206-0001, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
- Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan.
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8
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Yang CJ, Takeda M, Terauchi T, Jee J, Kainosho M. Differential Large-Amplitude Breathing Motions in the Interface of FKBP12–Drug Complexes. Biochemistry 2015; 54:6983-95. [DOI: 10.1021/acs.biochem.5b00820] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Chun-Jiun Yang
- Department
of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji,
Tokyo 192-0397, Japan
| | - Mitsuhiro Takeda
- Structural
Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho,
Chikusa-ku, Nagoya 464-8602, Japan
| | - Tsutomu Terauchi
- Department
of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji,
Tokyo 192-0397, Japan
| | - JunGoo Jee
- Department
of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji,
Tokyo 192-0397, Japan
| | - Masatsune Kainosho
- Department
of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji,
Tokyo 192-0397, Japan
- Structural
Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho,
Chikusa-ku, Nagoya 464-8602, Japan
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Platzer G, Okon M, McIntosh LP. pH-dependent random coil (1)H, (13)C, and (15)N chemical shifts of the ionizable amino acids: a guide for protein pK a measurements. JOURNAL OF BIOMOLECULAR NMR 2014; 60:109-129. [PMID: 25239571 DOI: 10.1007/s10858-014-9862-y] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/09/2014] [Indexed: 06/03/2023]
Abstract
The pK a values and charge states of ionizable residues in polypeptides and proteins are frequently determined via NMR-monitored pH titrations. To aid the interpretation of the resulting titration data, we have measured the pH-dependent chemical shifts of nearly all the (1)H, (13)C, and (15)N nuclei in the seven common ionizable amino acids (X = Asp, Glu, His, Cys, Tyr, Lys, and Arg) within the context of a blocked tripeptide, acetyl-Gly-X-Gly-amide. Alanine amide and N-acetyl alanine were used as models of the N- and C-termini, respectively. Together, this study provides an essentially complete set of pH-dependent intra-residue and nearest-neighbor reference chemical shifts to help guide protein pK a measurements. These data should also facilitate pH-dependent corrections in algorithms used to predict the chemical shifts of random coil polypeptides. In parallel, deuterium isotope shifts for the side chain (15)N nuclei of His, Lys, and Arg in their positively-charged and neutral states were also measured. Along with previously published results for Asp, Glu, Cys, and Tyr, these deuterium isotope shifts can provide complementary experimental evidence for defining the ionization states of protein residues.
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Affiliation(s)
- Gerald Platzer
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Takeda M, Miyanoiri Y, Terauchi T, Yang CJ, Kainosho M. Use of H/D isotope effects to gather information about hydrogen bonding and hydrogen exchange rates. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 241:148-154. [PMID: 24656087 DOI: 10.1016/j.jmr.2013.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/02/2013] [Accepted: 10/04/2013] [Indexed: 06/03/2023]
Abstract
Polar side-chains in proteins play important roles in forming and maintaining three-dimensional structures, and thus participate in various biological functions. Until recently, most protein NMR studies have focused on the non-exchangeable protons of amino acid residues. The exchangeable protons attached to polar groups, such as hydroxyl (OH), sulfhydryl (SH), and amino (NH2) groups, have mostly been ignored, because in many cases these hydrogen atoms exchange too quickly with water protons, making NMR observations impractical. However, in certain environments, such as deep within the hydrophobic interior of a protein, or in a strong hydrogen bond to other polar groups or interacting ligands, the protons attached to polar groups may exhibit slow hydrogen exchange rates and thus become NMR accessible. To explore the structural and biological implications of the interactions involving polar side-chains, we have developed versatile NMR methods to detect such cases by observing the line shapes of (13)C NMR signals near the polar groups, which are affected by deuterium-proton isotope shifts in a mixture of H2O and D2O. These methods allow the detection of polar side-chains with slow hydrogen-deuterium exchange rates, and therefore provide opportunities to retrieve information about the polar side-chains, which might otherwise be overlooked by conventional NMR experiments. Future prospects of applications using deuterium-proton isotope shifts to retrieve missing structural and dynamic information of proteins are discussed.
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Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yohei Miyanoiri
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Tsutomu Terauchi
- Center for Priority Areas, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji 192-0397, Japan; SAIL Technologies Co., Inc., 1-40 Suehiro-cho 1-chome, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Chun-Jiun Yang
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan; Center for Priority Areas, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji 192-0397, Japan.
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11
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Cao Z, Bowie JU. An energetic scale for equilibrium H/D fractionation factors illuminates hydrogen bond free energies in proteins. Protein Sci 2014; 23:566-75. [PMID: 24501090 DOI: 10.1002/pro.2435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 01/29/2014] [Accepted: 01/29/2014] [Indexed: 11/09/2022]
Abstract
Equilibrium H/D fractionation factors have been extensively employed to qualitatively assess hydrogen bond strengths in protein structure, enzyme active sites, and DNA. It remains unclear how fractionation factors correlate with hydrogen bond free energies, however. Here we develop an empirical relationship between fractionation factors and free energy, allowing for the simple and quantitative measurement of hydrogen bond free energies. Applying our empirical relationship to prior fractionation factor studies in proteins, we find: [1] Within the folded state, backbone hydrogen bonds are only marginally stronger on average in α-helices compared to β-sheets by ∼0.2 kcal/mol. [2] Charge-stabilized hydrogen bonds are stronger than neutral hydrogen bonds by ∼2 kcal/mol on average, and can be as strong as -7 kcal/mol. [3] Changes in a few hydrogen bonds during an enzyme catalytic cycle can stabilize an intermediate state by -4.2 kcal/mol. [4] Backbone hydrogen bonds can make a large overall contribution to the energetics of conformational changes, possibly playing an important role in directing conformational changes. [5] Backbone hydrogen bonding becomes more uniform overall upon ligand binding, which may facilitate participation of the entire protein structure in events at the active site. Our energetic scale provides a simple method for further exploration of hydrogen bond free energies.
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Affiliation(s)
- Zheng Cao
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, California
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12
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Tugarinov V. Indirect use of deuterium in solution NMR studies of protein structure and hydrogen bonding. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 77:49-68. [PMID: 24411830 DOI: 10.1016/j.pnmrs.2013.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/15/2013] [Indexed: 06/03/2023]
Abstract
A description of the utility of deuteration in protein NMR is provided with an emphasis on quantitative evaluation of the effects of deuteration on a number of NMR parameters of proteins: (1) chemical shifts, (2) scalar coupling constants, (3) relaxation properties (R1 and R2 rates) of nuclei directly attached to one or more deuterons as well as protons of methyl groups in a highly deuterated environment, (4) scalar relaxation of 15N and 13C nuclei in 15N-D and 13C-D spin systems as a measure of hydrogen bonding strength, and (5) NOE-based applications of deuteration in NMR studies of protein structure. The discussion is restricted to the 'indirect' use of deuterium in the sense that the description of NMR parameters and properties of the nuclei affected by nearby deuterons (15N, 13C, 1H) is provided rather than those of deuterium itself.
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Affiliation(s)
- Vitali Tugarinov
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, United States.
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13
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Kövér KE, Batta G. NMR investigation of disulfide containing peptides and proteins. AMINO ACIDS, PEPTIDES AND PROTEINS 2013:37-59. [DOI: 10.1039/9781849737081-00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Peptides and proteins with disulfide bonds are abundant in all kingdoms and play essential role in many biological events. Because small disulfide-rich peptides (proteins) are usually difficult to crystallize, nuclear magnetic resonance (NMR) is by far one of the most powerful techniques for the determination of their solution structure. Besides the “static” three-dimensional structure, NMR has unique opportunities to acquire additional information about molecular dynamics and folding at atomic resolution. Nowadays it is becoming increasingly evident, that “excited”, “disordered” or “fuzzy” protein states may exhibit biological function and disulfide proteins are also promising targets for such studies. In this short two-three years overview those disulfide peptides and proteins were cited from the literature that were studied by NMR. Though we may have missed some, their structural diversity and complexity as well as their wide repertoire of biological functions is impressive. We emphasised especially antimicrobial peptides and peptide based toxins in addition to some biologically important other structures. Besides the general NMR methods we reviewed some contemporary techniques suitable for disclosing the peculiar properties of disulfide bonds. Interesting dynamics and folding studies of disulfide proteins were also mentioned. It is important to disclose the essential structure, dynamics, function aspects of disulfide proteins since this aids the design of new compounds with improved activity and reduced toxicity. Undoubtedly, NMR has the potential to accelerate the development of new disulfide peptides/proteins with pharmacological activity.
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Tugarinov V. Four-bond deuterium isotope effects on the chemical shifts of amide nitrogens in proteins. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:722-728. [PMID: 24038445 DOI: 10.1002/mrc.4007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 07/19/2013] [Accepted: 08/18/2013] [Indexed: 06/02/2023]
Abstract
An approach towards precision NMR measurements of four-bond deuterium isotope effects on the chemical shifts of backbone amide nitrogen nuclei in proteins is described. Three types of four-bond (15) N deuterium isotope effects are distinguished depending on the site of proton-to-deuterium substitution: (4)ΔN(N(i-1)D), (4)ΔN(N(i+1)D) and (4)ΔN(Cβ,(i-1)D). All the three types of isotope shifts are quantified in the (partially) deuterated protein ubiquitin. The (4)ΔN(N(i+1)D) and (4)ΔN(C(β,i-1)D) effects are by far the largest in magnitude and vary between 16 and 75 ppb and -18 and 46 ppb, respectively. A semi-quantitative correlation between experimental (4)ΔN(N(i+1)D) and (4)ΔN(C(β,i-1)D) values and the distances between nitrogen nuclei and the sites of (1)H-to-D substitution is noted. The largest isotope shifts in both cases correspond to the shortest inter-nuclear distances.
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Affiliation(s)
- Vitali Tugarinov
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
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15
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Ma S, Zhao S, Zhang Y, Yu Y, Liu J, Xu M. Quality characteristic of spray-drying egg white powders. Mol Biol Rep 2013; 40:5677-83. [DOI: 10.1007/s11033-013-2669-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 09/14/2013] [Indexed: 11/30/2022]
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16
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Zhang D, Tugarinov V. Accurate measurements of the effects of deuteration at backbone amide positions on the chemical shifts of ¹⁵N, ¹³Cα, ¹³Cβ, ¹³CO and ¹Hα nuclei in proteins. JOURNAL OF BIOMOLECULAR NMR 2013; 56:169-182. [PMID: 23612994 DOI: 10.1007/s10858-013-9733-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/18/2013] [Indexed: 06/02/2023]
Abstract
An approach towards accurate NMR measurements of deuterium isotope effects on the chemical shifts of all backbone nuclei in proteins ((15)N, (13)Cα, (13)CO, (1)Hα) and (13)Cβ nuclei arising from (1)H-to-D substitutions at amide nitrogen positions is described. Isolation of molecular species with a defined protonation/deuteration pattern at successive backbone nitrogen positions in the polypeptide chain allows quantifying all deuterium isotope shifts of these nuclei from the first to the fourth order. Some of the deuterium isotope shifts measured in the proteins ubiquitin and GB1 can be interpreted in terms of backbone geometry via empirical relationships describing their dependence on (φ; ψ) backbone dihedral angles. Because of their relatively large variability and notable dependence on the protein secondary structure, the two- and three-bond (13)Cα isotope shifts, (2)ΔCα(NiD) and (3)ΔCα(Ni+1D), and three-bond (13)Cβ isotope shifts, (3)ΔCβ(NiD), are useful reporters of the local geometry of the protein backbone.
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Affiliation(s)
- Daoning Zhang
- Department of Chemistry and Biochemistry, University of Maryland, Biomolecular Sci. Bldg./CBSO, College Park, MD 20742, USA
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17
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Sun H, Long D, Brüschweiler R, Tugarinov V. Carbon Relaxation in 13Cα–Hα and 13Cα–Dα Spin Pairs as a Probe of Backbone Dynamics in Proteins. J Phys Chem B 2013; 117:1308-20. [DOI: 10.1021/jp312292k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hechao Sun
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - Dong Long
- Chemical Sciences Laboratory,
Department of Chemistry and Biochemistry and the National High Magnetic
Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
| | - Rafael Brüschweiler
- Chemical Sciences Laboratory,
Department of Chemistry and Biochemistry and the National High Magnetic
Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
| | - Vitali Tugarinov
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
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18
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Sun H, Tugarinov V. Precision Measurements of Deuterium Isotope Effects on the Chemical Shifts of Backbone Nuclei in Proteins: Correlations with Secondary Structure. J Phys Chem B 2012; 116:7436-48. [DOI: 10.1021/jp304300n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hechao Sun
- Department
of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Vitali Tugarinov
- Department
of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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19
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Takeda M, Terauchi T, Kainosho M. Conformational analysis by quantitative NOE measurements of the β-proton pairs across individual disulfide bonds in proteins. JOURNAL OF BIOMOLECULAR NMR 2012; 52:127-139. [PMID: 22131165 DOI: 10.1007/s10858-011-9587-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/08/2011] [Indexed: 05/31/2023]
Abstract
NOEs between the β-protons of cysteine residues across disulfide bonds in proteins provide direct information on the connectivities and conformations of these important cross-links, which are otherwise difficult to investigate. With conventional [U-(13)C, (15)N]-proteins, however, fast spin diffusion processes mediated by strong dipolar interactions between geminal β-protons prohibit the quantitative measurements and thus the analyses of long-range NOEs across disulfide bonds. We describe a robust approach for alleviating such difficulties, by using proteins selectively labeled with an equimolar mixture of (2R, 3S)-[β-(13)C; α,β-(2)H(2)] Cys and (2R, 3R)-[β-(13)C; α,β-(2)H(2)] Cys, but otherwise fully deuterated. Since either one of the prochiral methylene protons, namely β2 (proS) or β3 (proR), is always replaced with a deuteron and no other protons remain in proteins prepared by this labeling scheme, all four of the expected NOEs for the β-protons across disulfide bonds could be measured without any spin diffusion interference, even with long mixing times. Therefore, the NOEs for the β2 and β3 pairs across each of the disulfide bonds could be observed at high sensitivity, even though they are 25% of the theoretical maximum for each pair. With the NOE information, the disulfide bond connectivities can be unambiguously established for proteins with multiple disulfide bonds. In addition, the conformations around disulfide bonds, namely χ(2) and χ(3), can be determined based on the precise proton distances of the four β-proton pairs, by quantitative measurements of the NOEs across the disulfide bonds. The feasibility of this method is demonstrated for bovine pancreatic trypsin inhibitor, which has three disulfide bonds.
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Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
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20
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Miyanoiri Y, Takeda M, Kainosho M. Stereo-Array Isotope Labeling Method for Studying Protein Structure and Dynamics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 992:83-93. [DOI: 10.1007/978-94-007-4954-2_5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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21
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Takeda M, Jee J, Ono AM, Terauchi T, Kainosho M. Hydrogen Exchange Study on the Hydroxyl Groups of Serine and Threonine Residues in Proteins and Structure Refinement Using NOE Restraints with Polar Side-Chain Groups. J Am Chem Soc 2011; 133:17420-7. [DOI: 10.1021/ja206799v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - JunGoo Jee
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Akira M. Ono
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Tsutomu Terauchi
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
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22
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Hanashima S, Kato K, Yamaguchi Y. 13C-NMR quantification of proton exchange at LewisX hydroxyl groups in water. Chem Commun (Camb) 2011; 47:10800-2. [PMID: 21892456 DOI: 10.1039/c1cc13310a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NMR-based analysis of glycans by directly observing hydroxyl protons has been difficult because of their inherently fast exchange with water. We observed hydroxyl proton exchanges in a LewisX-LewisX interaction by using deuterium isotope shifts on (13)C-NMR. This strategy is suitable for analyzing weak interactions by identifying involved protons.
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Affiliation(s)
- Shinya Hanashima
- Structural Glycobiology Team, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama, Japan
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23
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Yamaguchi Y, Kato K. Dynamics and Interactions of Glycoconjugates Probed by Stable-Isotope-Assisted NMR Spectroscopy. Methods Enzymol 2010; 478:305-22. [DOI: 10.1016/s0076-6879(10)78015-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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