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The database contains also a smaller amount of NMR data from carbohydrates, cofactors and ligands. [1] These data are crossreferenced to 3D structures in the PDB when available. The NMR data are provided in the NMR-STAR file format and a number of format conversion tools are available at the site to convert files from NMR-STAR to other formats. [1]
The exact value of chemical shift depends on molecular structure and the solvent, temperature, magnetic field in which the spectrum is being recorded and other neighboring functional groups. Hydrogen nuclei are sensitive to the hybridization of the atom to which the hydrogen atom is attached and to electronic effects. Nuclei tend to be ...
Propyl propanoate (also known as propyl propionate and n-propyl propionate) is the organic compound with the molecular formula C 6 H 12 O 2. It is the ester of propanol and propionic acid. Like most esters, propyl propanoate is a colorless liquid with a fruity odor. The scent of propyl propionate is described as a chemically tinged pineapple or ...
Some calculate chemical shifts for backbone and certain side chain atoms (C and N only) and still others are able to calculate shifts for all atoms (40 atom types). For chemical shift refinement there is a need for rapid calculation as thousands of structures are generated during a molecular dynamics or simulated annealing run and their ...
Structure determination by NMR has traditionally been a time-consuming process, requiring interactive analysis of the data by a highly trained scientist. There has been considerable interest in automating the process to increase the throughput of structure determination and to make protein NMR accessible to non-experts (See structural genomics ...
An isomeric form of propyl is obtained by moving the point of attachment from a terminal carbon atom to the central carbon atom, named isopropyl or 1-methylethyl. To maintain four substituents on each carbon atom, one hydrogen atom has to be moved from the middle carbon atom to the carbon atom which served as attachment point in the n -propyl ...
Example of chemical shift index. The chemical shift index or CSI is a widely employed technique in protein nuclear magnetic resonance spectroscopy that can be used to display and identify the location (i.e. start and end) as well as the type of protein secondary structure (beta strands, helices and random coil regions) found in proteins using only backbone chemical shift data [1] [2] The ...
H NMR spectrum of a solution of HD (labeled with red bars) and H 2 (blue bar). The 1:1:1 triplet arises from the coupling of the 1 H nucleus (I = 1/2) to the 2 H nucleus (I = 1). In NMR spectroscopy, isotopic effects on chemical shifts are typically small, far less than 1 ppm, the typical unit for measuring shifts. The 1 H NMR signals for 1 H 2 ...