| 1. |
- Andersson, Hanna, 1979, et al.
(författare)
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Assessing the Ability of Spectroscopic Methods to Determine the Difference in the Folding Propensities of Highly Similar beta-Hairpins
- 2017
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Ingår i: Acs Omega. - : American Chemical Society (ACS). - 2470-1343. ; 2:2, s. 508-516
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Tidskriftsartikel (refereegranskat)abstract
- We have evaluated the ability of nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopies to describe the difference in the folding propensities of two structurally highly similar cyclic beta-hairpins, comparing the outcome to that of molecular dynamics simulations. NAMFIS-type NMR ensemble analysis and CD spectroscopy were observed to accurately describe the consequence of altering a single interaction site, whereas a single-site C-13 NMR chemical shift melting curve-based technique was not.
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| 2. |
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| 3. |
- Andersson, Hanna, 1979, et al.
(författare)
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Solvent Effects on Nitrogen Chemical Shifts
- 2015
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Ingår i: Annual Reports on NMR Spectroscopy. - : Elsevier. - 0066-4103. - 9780128021231 ; 86, s. 73-210
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Forskningsöversikt (refereegranskat)abstract
- Due to significant developments in cryogenic probe technology and the easy access to inverse detection pulse programmes (HSQC, HMBC), the sensitivity of nitrogen NMR has lately vastly improved. As a consequence, nitrogen NMR has turned into a useful and commonly available tool for solution studies of molecular structure and properties for small organic compounds likewise biopolymers. The high sensitivity of the nitrogen lone pair to changes in the molecular environment, alterations in intra- and intermolecular interactions, and in molecular conformation along with its wide, up to 1200 ppm chemical shift dispersion make nitrogen NMR to an exceptionally sensitive reporter tool. The nitrogen chemical shift has been applied in various fields of chemistry, including for instance the studies of transition metal complexes, chemical reactions such as N-alkylation and N-oxidation, tautomerization, protonation–deprotonation equilibria, hydrogen and halogen bonding, and elucidation of molecular conformation and configuration. The 15N NMR data observed in the investigation of these molecular properties and processes is influenced by the medium it is acquired in. This influence may be due to direct coordination of solvent molecules to transition metal complexes, alteration of tautomerization equilibria, and solvent polarity induced electron density changes of conjugated systems, for example. Thus, the solvent may significantly alter the observed nitrogen NMR shifts. This review aims to provide an overview of solvent effects of practical importance, and discusses selected experimental reports from various subfields of chemistry.
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| 4. |
- Brath, Ulrika, et al.
(författare)
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Paramagnetic ligand tagging to identify protein binding sites
- 2015
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 137:35, s. 11391-11398
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Tidskriftsartikel (refereegranskat)abstract
- Transient biomolecular interactions are the cornerstones of the cellular machinery. The identification of the binding sites for low affinity molecular encounters is essential for the development of high affinity pharmaceuticals from weakly binding leads but is hindered by the lack of robust methodologies for characterization of weakly binding complexes. We introduce a paramagnetic ligand tagging approach that enables localization of low affinity protein–ligand binding clefts by detection and analysis of intermolecular protein NMR pseudocontact shifts, which are invoked by the covalent attachment of a paramagnetic lanthanoid chelating tag to the ligand of interest. The methodology is corroborated by identification of the low millimolar volatile anesthetic interaction site of the calcium sensor protein calmodulin. It presents an efficient route to binding site localization for low affinity complexes and is applicable to rapid screening of protein–ligand systems with varying binding affinity.
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| 5. |
- Niebling, Stephan, et al.
(författare)
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The Impact of Interchain Hydrogen Bonding on b-Hairpin Stability is Readily Predicted by Molecular Dynamics Simulation
- 2015
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Ingår i: Peptide Science. - : Wiley. - 1097-0282 .- 0006-3525. ; 104:6, s. 703-706
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Tidskriftsartikel (refereegranskat)abstract
- Peptides are frequently used model systems for protein folding. They are also gaining increased importance as therapeutics. Here, the ability of molecular dynamics (MD) simulation for describing the structure and dynamics of β-hairpin peptides was investigated, with special attention given to the impact of a single interstrand sidechain to sidechain interaction. The MD trajectories were compared to structural information gained from solution NMR. By assigning frames from restraint-free MD simulations to an intuitive hydrogen bond on/off pattern, folding ratios and folding pathways were predicted. The computed molecular model successfully reproduces the folding ratios determined by NMR, indicating that MD simulation may be straightforwardly used as a screening tool in β-hairpin design.
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