Related ArticlesModulation of intrinsic phi,psi propensities of amino acids by neighbouring residues in the coil regions of protein structures: NMR analysis and dissection of a beta-hairpin peptide.
J Mol Biol. 1998 Dec 18;284(5):1597-609
Authors: Griffiths-Jones SR, Sharman GJ, Maynard AJ, Searle MS
Analysis of residues in coil regions of protein structures presents a novel approach to deconvoluting the various competing factors which determine the intrinsic phi,psi propensities of amino acids free from the regular interactions associated with beta-strands and alpha-helices. We have considered the role of context on phi,psi preferences by examining the effects of neighbouring residues in modulating coil propensities within a data base of 512 high-resolution, low-homology structures. In the general case, when flanking residues are beta-branched or aromatic (Val, Ile, Tyr and Phe) the beta-propensity (Pbeta) increases significantly, largely due to steric effects between flanking residues. More subtle residue-specific effects are apparant when Pbeta values are examined in detail, showing "random coil" conformations to be highly sequence-dependent. The effects of flanking residues on phi distributions have been used to calculate context-dependent average 3JNH-Halpha coupling constants. We have examined these findings in the context of the folding of a model 16-residue beta-hairpin peptide, "mutant" hairpin (VSI-->KSK sequence change) and the isolated C-terminal beta-strand fragments of both hairpins. We find a better correlation between 3JNH-Halpha values derived from the data base model and those determined experimentally when context-dependent phi distributions are considered. The individual C-terminal beta-strand sequences (GKKITVSI versus GKKITKSK) of the two hairpins are predisposed to different extents to formation of an extended beta-like conformation. Conformational "predisposition" in this context may contribute significantly to beta-hairpin stability.
[Question from NMRWiki Q&A forum] 13C quaternary centers in amino acids
13C quaternary centers in amino acids
I've got a sample of about 5mg of an amino acid that is the final product of a a synthesis. Due to the long relaxation time that the carboxylic and the alpha C we only got a 200 varian Mercury instrument and we're unable to obtain those signals. I was wondering if an APT is better than DEPT, because we're only interested in this signals and i've heard the overall pulse sequence is shorter than the DEPT, increasing the number of scans in the same period of time.
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nmrlearner
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09-01-2011 07:20 AM
[Question from NMRWiki Q&A forum] 13C cuaternary centers in amino acids
13C cuaternary centers in amino acids
I've got a sample of about 5mg of an amino acid that is the final product of a a synthesis. Due to the long relaxation time that the carboxilic and the alpha C we only got a 200 varian Mercury instrument and we're unable to obtain those signals. I was wondering if an APT is better than DEPT, because we're only interested in this signals and i've heart the overall pulse sequence is shorter than the DEPT, increasing the number of scans in the same period of time
Check if somebody has answered this question on NMRWiki QA forum
nmrlearner
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08-31-2011 07:12 PM
[KPWU blog] Names of Atoms of Amino acids
Names of Atoms of Amino acids
I really hate the inconsistent nomenclature of atoms of amino acids between different programs/database. I finished all NOESY assignment on Sparky using PDB nomenclature and the Sparky XPLOR constraint plugin (shortcut xf) doesn’t take care of the differences between XPLOR and PDB. Thus I have to find a table showing me the differences of names http://stats.wordpress.com/b.gif?host=kpwu.wordpress.com&blog=76132&post=262&subd=kpwu&ref=&feed=1
Go to KPWU blog to read complete post.
nmrlearner
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01-28-2011 04:52 AM
[NMR paper] Assigning the NMR spectra of aromatic amino acids in proteins: analysis of two Ets po
Assigning the NMR spectra of aromatic amino acids in proteins: analysis of two Ets pointed domains.
Related Articles Assigning the NMR spectra of aromatic amino acids in proteins: analysis of two Ets pointed domains.
Biochem Cell Biol. 1998;76(2-3):379-90
Authors: Slupsky CM, Gentile LN, McIntosh LP
The measurement of interproton nuclear Overhauser enhancements (NOEs) and dihedral angle restraints of aromatic amino acids is a critical step towards determining the structure of a protein. The complete assignment of the resonances from aromatic...
nmrlearner
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11-17-2010 11:06 PM
[NMR paper] The solution conformations of amino acids from molecular dynamics simulations of Gly-
The solution conformations of amino acids from molecular dynamics simulations of Gly-X-Gly peptides: comparison with NMR parameters.
Related Articles The solution conformations of amino acids from molecular dynamics simulations of Gly-X-Gly peptides: comparison with NMR parameters.
Biochem Cell Biol. 1998;76(2-3):164-70
Authors: van der Spoel D
The conformations that amino acids can adopt in the random coil state are of fundamental interest in the context of protein folding research and studies of protein-peptide interactions. To date, no...
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11-17-2010 11:06 PM
[NMR paper] Comparison between the phi distribution of the amino acids in the protein database an
Comparison between the phi distribution of the amino acids in the protein database and NMR data indicates that amino acids have various phi propensities in the random coil conformation.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Comparison between the phi distribution of the amino acids in the protein database and NMR data indicates that amino acids have various phi propensities in the random coil conformation.
J Mol Biol. 1995 Nov 24;254(2):322-33
Authors: Serrano L
...
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08-22-2010 03:50 AM
[NMR paper] Involvement of various amino- and carboxyl-terminal residues in the active site of th
Involvement of various amino- and carboxyl-terminal residues in the active site of the histidine-containing protein HPr of the phosphoenolpyruvate-dependent phosphotransferase system of Staphylococcus carnosus: site-directed mutagenesis with the ptsH gene, biochemical characterization and NMR studies of the mutant proteins.
Related Articles Involvement of various amino- and carboxyl-terminal residues in the active site of the histidine-containing protein HPr of the phosphoenolpyruvate-dependent phosphotransferase system of Staphylococcus carnosus: site-directed mutagenesis with...
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08-21-2010 11:53 PM
[NMR paper] Proton NMR assignments of heme contacts and catalytically implicated amino acids in c
Proton NMR assignments of heme contacts and catalytically implicated amino acids in cyanide-ligated cytochrome c peroxidase determined from one- and two-dimensional nuclear Overhauser effects.
Related Articles Proton NMR assignments of heme contacts and catalytically implicated amino acids in cyanide-ligated cytochrome c peroxidase determined from one- and two-dimensional nuclear Overhauser effects.
Biochemistry. 1991 May 7;30(18):4398-405
Authors: Satterlee JD, Erman JE
Proton NMR assignments of the heme pocket and catalytically relevant...
Modulation of intrinsic phi,psi propensities of amino acids by neighbouring residues
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