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Treviño MÁ, López-Sánchez R, Moya MR, Pantoja-Uceda D, Mompeán M, Laurents DV. Insight into polyproline II helical bundle stability in an antifreeze protein denatured state. Biophys J 2022; 121:4560-4568. [PMID: 36815707 PMCID: PMC9748357 DOI: 10.1016/j.bpj.2022.10.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/06/2022] [Accepted: 10/24/2022] [Indexed: 11/02/2022] Open
Abstract
The use of polyproline II (PPII) helices in protein design is currently hindered by limitations in our understanding of their conformational stability and folding. Recent studies of the snow flea antifreeze protein (sfAFP), a useful model system composed of six PPII helices, suggested that a low denatured state entropy contributes to folding thermodynamics. Here, circular dichroism spectroscopy revealed minor populations of PPII like conformers at low temperature. To get atomic level information on the conformational ensemble and entropy of the reduced, denatured state of sfAFP, we have analyzed its chemical shifts and {1H}-15N relaxation parameters by NMR spectroscopy at four experimental conditions. No significant populations of stable secondary structure were detected. The stiffening of certain N-terminal residues at neutral versus acidic pH and shifted pKa values leads us to suggest that favorable charge-charge interactions could bias the conformational ensemble to favor the formation the C1-C28 disulfide bond during nascent folding, although no evidence for preferred contacts between these positions was detected by paramagnetic relaxation enhancement under denaturing conditions. Despite a high content of flexible glycine residues, the mobility of the sfAFP denatured ensemble is similar for denatured α/β proteins both on fast ps/ns as well as slower μs/ms timescales. These results are in line with a conformational entropy in the denatured ensemble resembling that of typical proteins and suggest that new structures based on PPII helical bundles should be amenable to protein design.
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Ramírez de Mingo D, Pantoja-Uceda D, Hervás R, Carrión-Vázquez M, Laurents DV. Conformational dynamics in the disordered region of human CPEB3 linked to memory consolidation. BMC Biol 2022; 20:129. [PMID: 35658951 PMCID: PMC9166367 DOI: 10.1186/s12915-022-01310-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 04/25/2022] [Indexed: 11/10/2022] Open
Abstract
Background Current understanding of the molecular basis of memory consolidation points to an important function of amyloid formation by neuronal-specific isoforms of the cytoplasmic polyadenylation element binding (CPEB) protein family. In particular, CPEB is thought to promote memory persistence through formation of self-sustaining prion-like amyloid assemblies at synapses, mediated by its intrinsically disordered region (IDR) and leading to permanent physical alterations at the basis of memory persistence. Although the molecular mechanisms by which amyloid formation takes place in CPEB have been described in invertebrates, the way amyloid formation occurs in the human homolog CPEB3 (hCPEB3) remains unclear. Here, we characterize by NMR spectroscopy the atomic level conformation and ps-ms dynamics of the 426-residue IDR of hCPEB3, which has been associated with episodic memory in humans. Results We show that the 426-residue N-terminal region of hCPEB3 is a dynamic, intrinsically disordered region (IDR) which lacks stable folded structures. The first 29 residues, M1QDDLLMDKSKTQPQPQQQQRQQQQPQP29, adopt a helical + disordered motif, and residues 86–93: P83QQPPPP93, and 166–175: P166PPPAPAPQP175 form polyproline II (PPII) helices. The (VG)5 repeat motif is completely disordered, and residues 200–250 adopt three partially populated α-helices. Residues 345–355, which comprise the nuclear localization signal (NLS), form a modestly populated α-helix which may mediate STAT5B binding. These findings allow us to suggest a model for nascent hCPEB3 structural transitions at single residue resolution, advancing that amyloid breaker residues, like proline, are a key difference between functional versus pathological amyloids. Conclusion Our NMR spectroscopic analysis of hCPEB3 provides insights into the first structural transitions involved in protein–protein and protein-mRNA interactions. The atomic level understanding of these structural transitions involved in hCPEB3 aggregation is a key first step toward understanding memory persistence in humans, as well as sequence features that differentiate beneficial amyloids from pathological ones. Areas Biophysics, Structural Biology, Biochemistry & Neurosciences. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01310-6.
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Mompeán M, Treviño MÁ, Laurents DV. Partial structure, dampened mobility, and modest impact of a His tag in the SARS-CoV-2 Nsp2 C-terminal region. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:1129-1137. [PMID: 34633480 PMCID: PMC8503394 DOI: 10.1007/s00249-021-01575-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/10/2021] [Accepted: 10/03/2021] [Indexed: 11/30/2022]
Abstract
Intrinsically disordered proteins (IDPs) play essential roles in regulating physiological processes in eukaryotic cells. Many viruses use their own IDPs to "hack" these processes to deactivate host defenses and promote viral growth. Thus, viral IDPs are attractive drug targets. While IDPs are hard to study by X-ray crystallography or cryo-EM, atomic level information on their conformational preferences and dynamics can be obtained using NMR spectroscopy. SARS-CoV-2 Nsp2, whose C-terminal region (CtR) is predicted to be disordered, interacts with human proteins that regulate translation initiation and endosome vesicle sorting. Molecules that block these interactions could be valuable leads for drug development. The 13Cβ and backbone 13CO, 1HN, 13Cα, and 15N nuclei of Nsp2's 45-residue CtR were assigned and used to characterize its structure and dynamics in three contexts; namely: (1) retaining an N-terminal His tag, (2) without the His tag and with an adventitious internal cleavage, and (3) lacking both the His tag and the internal cleavage. Two five-residue segments adopting a minor extended population were identified. Overall, the dynamic behavior is midway between a completely rigid and a fully flexible chain. Whereas the presence of an N-terminal His tag and internal cleavage stiffen and loosen, respectively, neighboring residues, they do not affect the tendency of two regions to populate extended conformations.
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Affiliation(s)
- Miguel Mompeán
- "Rocasolano" Institute for Physical Chemistry, Spanish National Research Council, Serrano 119, 28006, Madrid, Spain
| | - Miguel Á Treviño
- "Rocasolano" Institute for Physical Chemistry, Spanish National Research Council, Serrano 119, 28006, Madrid, Spain
| | - Douglas V Laurents
- "Rocasolano" Institute for Physical Chemistry, Spanish National Research Council, Serrano 119, 28006, Madrid, Spain.
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Chaves-Arquero B, Pantoja-Uceda D, Roque A, Ponte I, Suau P, Jiménez MA. A CON-based NMR assignment strategy for pro-rich intrinsically disordered proteins with low signal dispersion: the C-terminal domain of histone H1.0 as a case study. JOURNAL OF BIOMOLECULAR NMR 2018; 72:139-148. [PMID: 30414042 DOI: 10.1007/s10858-018-0213-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/24/2018] [Indexed: 05/23/2023]
Abstract
The C-terminal domain of histone H1.0 (C-H1.0) is involved in DNA binding and is a main determinant of the chromatin condensing properties of histone H1.0. Phosphorylation at the (S/T)-P-X-(K/R) motifs affects DNA binding and is crucial for regulation of C-H1.0 function. Since C-H1.0 is an intrinsically disordered domain, solution NMR is an excellent approach to characterize the effect of phosphorylation on the structural and dynamic properties of C-H1.0. However, its very repetitive, low-amino acid-diverse and Pro-rich sequence, together with the low signal dispersion observed at the 1H-15N HSQC spectra of both non- and tri-phosphorylated C-H1.0 preclude the use of standard 1H-detected assignment strategies. We have achieved an essentially complete assignment of the heavy backbone atoms (15N, 13C' and 13Cα), as well as 1HN and 13Cβ nuclei, of non- and tri-phosphorylated C-H1.0 by applying a novel 13C-detected CON-based strategy. No C-H1.0 region with a clear secondary structure tendency was detected by chemical shift analyses, confirming at residue level that C-H1.0 is disordered in aqueous solution. Phosphorylation only affected the chemical shifts of phosphorylated Thr's, and their adjacent residues. Heteronuclear {1H}-15N NOEs were also essentially equal in the non- and tri-phosphorylated states. Hence, structural tendencies and dynamic properties of C-H1.0 free in aqueous solution are unmodified by phosphorylation. We propose that the assignment strategy used for C-H1.0, which is based on the acquisition of only a few 3D spectra, is an excellent choice for short-lived intrinsically disordered proteins with repetitive sequences.
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Affiliation(s)
- Belén Chaves-Arquero
- Departamento de Química-Física Biológica, Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006, Madrid, Spain
| | - David Pantoja-Uceda
- Departamento de Química-Física Biológica, Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006, Madrid, Spain
| | - Alicia Roque
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Inmaculada Ponte
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - Pedro Suau
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona (UAB), Bellaterra, Barcelona, Spain
| | - M Angeles Jiménez
- Departamento de Química-Física Biológica, Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006, Madrid, Spain.
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Gutiérrez-Fernández J, Saleh M, Alcorlo M, Gómez-Mejía A, Pantoja-Uceda D, Treviño MA, Voß F, Abdullah MR, Galán-Bartual S, Seinen J, Sánchez-Murcia PA, Gago F, Bruix M, Hammerschmidt S, Hermoso JA. Modular Architecture and Unique Teichoic Acid Recognition Features of Choline-Binding Protein L (CbpL) Contributing to Pneumococcal Pathogenesis. Sci Rep 2016; 6:38094. [PMID: 27917891 PMCID: PMC5137146 DOI: 10.1038/srep38094] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 11/04/2016] [Indexed: 12/27/2022] Open
Abstract
The human pathogen Streptococcus pneumoniae is decorated with a special class of surface-proteins known as choline-binding proteins (CBPs) attached to phosphorylcholine (PCho) moieties from cell-wall teichoic acids. By a combination of X-ray crystallography, NMR, molecular dynamics techniques and in vivo virulence and phagocytosis studies, we provide structural information of choline-binding protein L (CbpL) and demonstrate its impact on pneumococcal pathogenesis and immune evasion. CbpL is a very elongated three-module protein composed of (i) an Excalibur Ca2+-binding domain -reported in this work for the very first time-, (ii) an unprecedented anchorage module showing alternate disposition of canonical and non-canonical choline-binding sites that allows vine-like binding of fully-PCho-substituted teichoic acids (with two choline moieties per unit), and (iii) a Ltp_Lipoprotein domain. Our structural and infection assays indicate an important role of the whole multimodular protein allowing both to locate CbpL at specific places on the cell wall and to interact with host components in order to facilitate pneumococcal lung infection and transmigration from nasopharynx to the lungs and blood. CbpL implication in both resistance against killing by phagocytes and pneumococcal pathogenesis further postulate this surface-protein as relevant among the pathogenic arsenal of the pneumococcus.
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Affiliation(s)
- Javier Gutiérrez-Fernández
- Department of Crystallography and Structural Biology, "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Malek Saleh
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - Martín Alcorlo
- Department of Crystallography and Structural Biology, "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Alejandro Gómez-Mejía
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - David Pantoja-Uceda
- Department of Biological Physical Chemistry. "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Miguel A Treviño
- Department of Biological Physical Chemistry. "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Franziska Voß
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - Mohammed R Abdullah
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - Sergio Galán-Bartual
- Department of Crystallography and Structural Biology, "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Jolien Seinen
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - Pedro A Sánchez-Murcia
- Department of Biomedical Sciences, Unidad Asociada al IQM-CSIC, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid, Spain
| | - Federico Gago
- Department of Biomedical Sciences, Unidad Asociada al IQM-CSIC, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid, Spain
| | - Marta Bruix
- Department of Biological Physical Chemistry. "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
| | - Sven Hammerschmidt
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, D-17487 Greifswald, Germany
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, "Rocasolano" Institute of Physical-Chemistry, CSIC, Serrano 119, E-28006-Madrid, Spain
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Kumar D, Raikwal N, Shukla VK, Pandey H, Arora A, Guleria A. Pseudo 5D HN(C)N experiment to facilitate the assignment of backbone resonances in proteins exhibiting high backbone shift degeneracy. Chem Phys 2014. [DOI: 10.1016/j.chemphys.2014.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Pantoja-Uceda D, Santoro J. Direct correlation of consecutive C'-N groups in proteins: a method for the assignment of intrinsically disordered proteins. JOURNAL OF BIOMOLECULAR NMR 2013; 57:57-63. [PMID: 23929272 DOI: 10.1007/s10858-013-9765-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/24/2013] [Indexed: 05/21/2023]
Abstract
Two novel 3D (13)C-detected experiments, hNcocaNCO and hnCOcaNCO, are proposed to facilitate the resonance assignment of intrinsically disordered proteins. The experiments correlate the (15)N and (13)C' chemical shifts of two consecutive amide moieties without involving other nuclei, thus taking advantage of the good dispersion shown by the (15)N-(13)C' correlations, even for proteins that lack a well defined tertiary structure. The new pulse sequences were successfully tested using Nupr1, an intrinsically disordered protein of 93 residues.
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Affiliation(s)
- David Pantoja-Uceda
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006, Madrid, Spain
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Rout MK, Mishra P, Atreya HS, Hosur RV. Reduced dimensionality 3D HNCAN for unambiguous HN, CA and N assignment in proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 216:161-168. [PMID: 22370721 DOI: 10.1016/j.jmr.2012.01.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 01/16/2012] [Accepted: 01/28/2012] [Indexed: 05/31/2023]
Abstract
We present here an improvisation of HNN (Panchal, Bhavesh et al., 2001) called RD 3D HNCAN for backbone (HN, CA and (15)N) assignment in both folded and unfolded proteins. This is a reduced dimensionality experiment which employs CA chemical shifts to improve dispersion. Distinct positive and negative peak patterns of various triplet segments along the polypeptide chain observed in HNN are retained and these provide start and check points for the sequential walk. Because of co-incrementing of CA and (15)N, peaks along one of the dimensions appear at sums and differences of the CA and (15)N chemical shifts. This changes the backbone assignment protocol slightly and we present this in explicit detail. The performance of the experiment has been demonstrated using Ubiquitin and Plasmodium falciparum P2 proteins. The experiment is particularly valuable when two neighboring amino acid residues have nearly identical backbone (15)N chemical shifts.
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Affiliation(s)
- Manoj Kumar Rout
- Department of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), Mumbai 400 005, India
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Rodríguez-Rodríguez M, Treviño MA, Laurents DV, Arranz R, Valpuesta JM, Rico M, Bruix M, Jiménez MA. Characterization of the structure and self-recognition of the human centrosomal protein NA14: implications for stability and function. Protein Eng Des Sel 2011; 24:883-92. [PMID: 22008182 DOI: 10.1093/protein/gzr050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The protein NA14 is a key adaptor protein mediating the intermolecular interactions of microtubules and Spastin. To gain insight into its structure and function, we have expressed, purified and characterized human NA14 and some variants. NA14 is rather insoluble and tends to oligomerize and form fibrils. Successive mutation of the three Cys and two potentially exposed Leu residues (83 and 93) yielded a water-soluble quintuple variant, named 3CS-2LR. NA14 and its variants have a high helical content as determined by circular dichroism (CD). Based on nuclear magnetic resonance data of the quintuple mutant and the wild-type (wt) protein in the presence of dodecylphosphocholine micelles, the N-(M1-N13) and C-termini (K105-S119) were found to lack preferred structure. The remaining residues (14-104) participate in NA14 self-association, probably by forming a parallel coiled-coil structure. We hypothesize that Leu 83 and Leu 93 mediate interactions among NA14, Spastin and microtubules. We have also examined urea and thermal denaturation of the quintuple and other NA14 variants at different pH values by CD. The pH dependence of the conformational stability and the elevated native-state pK(a) determined for the two conserved Tyr allow us to propose that the NA14 structure may be stabilized by two Glu-COO(-) ||| HO-Tyr H-bonds, highly conserved in NA14-like proteins in other species.
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Affiliation(s)
- Mar Rodríguez-Rodríguez
- Departamento de Química Física Biológica, Instituto de Química Física Rocasolano, CSIC, Serrano-119, 28006 Madrid, Spain
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Kumar D, Hosur RV. hNCOcanH pulse sequence and a robust protocol for rapid and unambiguous assignment of backbone ((1)H(N), (15)N and (13)C') resonances in (15)N/(13)C-labeled proteins. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:575-583. [PMID: 21818779 DOI: 10.1002/mrc.2787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/23/2011] [Accepted: 05/23/2011] [Indexed: 05/31/2023]
Abstract
A three-dimensional nuclear magnetic resonance (NMR) pulse sequence named as hNCOcanH has been described to aid rapid sequential assignment of backbone resonances in (15)N/(13)C-labeled proteins. The experiment has been derived by a simple modification of the previously described HN(C)N pulse sequence [Panchal et al., J. Biomol. NMR 20 (2001) 135-147]; t2 evolution is used to frequency label (13)C' rather than (15)N (similar trick has also been used in the design of hNCAnH pulse sequence from hNcaNH [Frueh et al., JACS, 131 (2009) 12880-12881]). The modification results in a spectrum equivalent to HNCO, but in addition to inter-residue correlation peaks (i.e. Hi , Ci-1), the spectrum also contains additional intra-residue correlation peaks (i.e. Hi-1 , Ci-1) in the direct proton dimension which has maximum resolution. This is the main strength of the experiment and thus, even a small difference in amide (1) H chemical shifts (5-6 Hz) can be used for establishing a sequential connectivity. This experiment in combination with the HNN experiment described previously [Panchal et al., J. Biomol. NMR 20 (2001) 135-147] leads to a more robust assignment protocol for backbone resonances ((1) H(N) , (15)N) than could be derived from the combination of HNN and HN(C)N experiments [Bhavesh et al., Biochemistry, 40 (2001) 14727-14735]. Further, this new protocol enables assignment of (13)C' resonances as well. We believe that the experiment and the protocol presented here will be of immense value for structural-and functional-proteomics research by NMR. Performance of this experiment has been demonstrated using (13)C/(15)N labeled ubiquitin.
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Affiliation(s)
- Dinesh Kumar
- Center of Biomedical Magnetic Resonance, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raibareli Road, Lucknow 226014, Uttar Pradesh, India; Department of Chemical Sciences, Tata Institute of Fundamental Research, 1-Homi Bhabha Road, Colaba, Mumbai 400005, India
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Wilcox DS, Hotopp KM, Dian BC. Two-dimensional chirped-pulse Fourier transform microwave spectroscopy. J Phys Chem A 2011; 115:8895-905. [PMID: 21728367 DOI: 10.1021/jp2043202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two-dimensional (2D) correlation techniques are developed for chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy. The broadband nature of the spectrometer coupled with fast digital electronics permits the generation of arbitrary pulse sequences and simultaneous detection of the 8-18 GHz region of the microwave spectrum. This significantly increases the number of rotation transitions that can be simultaneously probed, as well as the bandwidth in both frequency dimensions. We theoretically and experimentally evaluate coherence transfer of three- and four-level systems to relate the method with previous studies. We then extend the principles of single-quantum and autocorrelation to incorporate broadband excitation and detection. Global connectivity of the rotational energy level structure is demonstrated through the transfer of multiple coherences in a single 2D experiment. Additionally, open-system effects are observed from irradiating many-level systems. Quadrature detection in the indirectly measured frequency dimension and phase cycling are also adapted for 2D CP-FTMW spectroscopy.
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Affiliation(s)
- David S Wilcox
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana, 47907-2084, USA
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