Random coil chemical shifts are commonly used to detect secondary structure elements in proteins in chemical shift index calculations. While this technique is very reliable for folded proteins, application to unfolded proteins reveals significant deviations from measured random coil shifts for certain nuclei. While some of these deviations can be ascribed to residual structure in the unfolded protein, others are clearly caused by local sequence effects. In particular, the amide nitrogen, amide proton, and carbonyl carbon chemical shifts are highly sensitive to the local amino acid sequence. We present a detailed, quantitative analysis of the effect of the 20 naturally occurring amino acids on the random coil shifts of (15)N(H), (1)H(N), and (13)CO resonances of neighboring residues, utilizing complete resonance assignments for a set of five-residue peptides Ac-G-G-X-G-G-NH(2). The work includes a validation of the concepts used to derive sequence-dependent correction factors for random coil chemical shifts, and a comprehensive tabulation of sequence-dependent correction factors that can be applied for amino acids up to two residues from a given position. This new set of correction factors will have important applications to folded proteins as well as to short, unstructured peptides and unfolded proteins.
CS23D - generating protein structure from NMR chemical shifts and sequence homology
CS23D website
CS23D is a web server for rapidly generating accurate 3D protein structures using only assigned NMR chemical shifts as input. CS23D uses a combination of maximal subfragment assembly, chemical shift threading, shift-based torsion angle prediction and chemical shift refinement to generate and refine the protein coordinates. CS23D accepts chemical shift files in either SHIFTY or BMRB formats and produces a set of PDB coordinates for the protein normally within 10-15 minutes (3 hours max). CS23D performance is dependent on the completeness of the chemical shift assignments and...
markber
NMR software
0
02-23-2012 09:40 PM
RCI - Random Coil Index for predicting protein flexibility from chemical shifts
RCI website
RCI method predicts protein flexibility by calculating the Random Coil Index from backbone chemical shifts and predicting values of model-free order parameters as well as per-residue RMSF of NMR and MD ensembles from the Random Coil Index.
The key advantages of this protocol over existing methods of studying protein flexibility are (i) it does not require prior knowledge of a protein's tertiary structure, (ii) it is not sensitive to the protein's overall tumbling and (iii) it does not require additional NMR measurements beyond the standard experiments for backbone...
markber
NMR software
0
02-02-2012 11:36 PM
Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution
Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution
Abstract Random coil chemical shifts are necessary for secondary chemical shift analysis, which is the main NMR method for identification of secondary structure in proteins. One of the largest challenges in the determination of random coil chemical shifts is accounting for the effect of neighboring residues. The contributions from the neighboring residues are typically removed by using neighbor correction factors determined based on each...
nmrlearner
Journal club
0
06-06-2011 12:53 AM
Random coil chemical shift for intrinsically disordered proteins: effects of temperature and pH
Random coil chemical shift for intrinsically disordered proteins: effects of temperature and pH
Abstract Secondary chemical shift analysis is the main NMR method for detection of transiently formed secondary structure in intrinsically disordered proteins. The quality of the secondary chemical shifts is dependent on an appropriate choice of random coil chemical shifts. We report random coil chemical shifts and sequence correction factors determined for a GGXGG peptide series following the approach of Schwarzinger et al. (J Am Chem Soc 123(13):2970â??2978, 2001). The chemical shifts are...
nmrlearner
Journal club
0
01-17-2011 02:40 AM
[NMR paper] Proline-directed random-coil chemical shift values as a tool for the NMR assignment o
Proline-directed random-coil chemical shift values as a tool for the NMR assignment of the tau phosphorylation sites.
Related Articles Proline-directed random-coil chemical shift values as a tool for the NMR assignment of the tau phosphorylation sites.
Chembiochem. 2004 Jan 3;5(1):73-8
Authors: Lippens G, Wieruszeski JM, Leroy A, Smet C, Sillen A, Buée L, Landrieu I
NMR spectroscopy of the full-length neuronal Tau protein has proved to be difficult due to the length of the protein and the unfavorable amino acid composition. We show that the...
nmrlearner
Journal club
0
11-24-2010 09:25 PM
[NMR paper] The NMR solution structure and characterization of pH dependent chemical shifts of th
The NMR solution structure and characterization of pH dependent chemical shifts of the beta-elicitin, cryptogein.
Related Articles The NMR solution structure and characterization of pH dependent chemical shifts of the beta-elicitin, cryptogein.
J Biomol NMR. 1998 Nov;12(4):523-34
Authors: Gooley PR, Keniry MA, Dimitrov RA, Marsh DE, Keizer DW, Gayler KR, Grant BR
The NMR structure of the 98 residue beta-elicitin, cryptogein, which induces a defence response in tobacco, was determined using 15N and 13C/15N labelled protein samples. In aqueous...
nmrlearner
Journal club
0
11-17-2010 11:15 PM
Prediction of Xaa-Pro peptide bond conformation from sequence and chemical shifts
Abstract We present a program, named Promega, to predict the Xaa-Pro peptide bond conformation on the basis of backbone chemical shifts and the amino acid sequence. Using a chemical shift database of proteins of known structure together with the PDB-extracted amino acid preference of cis Xaa-Pro peptide bonds, a cis/trans probability score is calculated from the backbone and 13Cβ chemical shifts of the proline and its neighboring residues. For an arbitrary number of input chemical shifts, which may include Pro-13Cγ, Promega calculates the statistical probability that a Xaa-Pro peptide bond...
nmrlearner
Journal club
0
08-14-2010 04:19 AM
Chemical shift prediction in random coil peptides
Please check this program and let me know if it does work for your random coil peptides.
http://bloch.anu.edu.au/cgi-bin/shiftpred/shiftpred.cgi
Thank you,
Bogdan Bancia
bbancia@yahoo.com