Publication year: 2012 Source:Journal of Magnetic Resonance
Beat Vögeli
Cross-correlated relaxation (CCR) rates are an established tool for the extraction of relative bond orientations in biomolecules in solution. CCR between dipolar interactions in four-spin systems is a particularly well-suited mechanism. In this paper, a simple approach to analyze systematic experimental errors is formulated in a subspace of the complete four-spin Hilbert space. It is shown that, contrary to the common assumption, the secular approximation of the relaxation matrix is marginal for the most prominent spin systems. With the main focus on the model protein GB3 at room temperature, it is shown that the apparent experimental CCR rates have errors between -12 and +4% for molecules with a molecular tumbling time of 3.5 ns. Although depending on the specific pulse sequence used, the following rule-of-thumb can be established: Judged by absolute values, the errors for H?-C?/H?-C?, HN-N/C?-C’, HN-N/C?-C? and HN-N/H?-C? CCR rates can safely be neglected. However, errors for HN-N/HN-N and HN-N/H?-C? CCR rates are on the order of 0.1 - 0.3 s-1 and must be considered. Tabulated correction factors may be used for their extraction. If larger systems are studied, in most cases the errors cannot be neglected anymore. On the other hand, well-calibrated pulses can safely be assumed to be perfect. Graphical abstract
Graphical abstract Highlights
? Secular approximations of the relaxation matrix are marginal even for small proteins. ? Tabulated correction factors may be used for the extraction of CCR rates. ? Errors of dipolar four-spin CCR rates can be on the order of 0.1 - 0.3 s-1.
[NMR paper] Water proton spin saturation affects measured protein backbone 15N spin relaxation rates
From Mendeley Biomolecular NMR group:
Water proton spin saturation affects measured protein backbone 15N spin relaxation rates
Journal of Magnetic Resonance (2011). Volume: 213, Issue: 1. Pages: 151-157. Kang Chen, Nico Tjandra et al.
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NMR Cross-Correlated Relaxation Rates Reveal Ion Coordination Sites in DNA
NMR Cross-Correlated Relaxation Rates Reveal Ion Coordination Sites in DNA
Radovan Fiala, Nad?a S?pac?kova?, Silvie Foldynova?-Tranti?rkova?, Jir?i? S?poner, Vladimi?r Sklena?r? and Luka?s? Tranti?rek
http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/0/jacsat.ahead-of-print/ja202397p/aop/images/medium/ja-2011-02397p_0003.gif
Journal of the American Chemical Society
DOI: 10.1021/ja202397p
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Side chain: backbone projections in aromatic and ASX residues from NMR cross-correlated relaxation
Side chain: backbone projections in aromatic and ASX residues from NMR cross-correlated relaxation
Abstract The measurements of cross-correlated relaxation rates between HNâ??N and Cβâ??Cγ intraresidual and sequential dipolar interactions is demonstrated in ASN, ASP and aromatic residues. The experiment can be used for deuterated samples and no additional knowledge such as Karplus parametrizations is required for the analysis. The data constitutes a new type of information since no other method relates the Cβâ??Cγ bond to HNâ??N. Using this method the dominant populations of rotamer...
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J Am Chem Soc. 2003 Aug 27;125(34):10420-8
Authors: Tugarinov V, Hwang PM, Ollerenshaw JE, Kay LE
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Biochemistry. 2001 Aug 14;40(32):9596-604
Authors: Schüler W, Kloiber K, Matt T, Bister K, Konrat R
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The derivation of a generalized relaxation matrix equation for the off-resonance rotating-frame spin-lattice...
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[NMR paper] Relaxation-matrix formalism for rotating-frame spin-lattice proton NMR relaxation and
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J Magn Reson B. 1994 May;104(1):11-25
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[NMR paper] Polarization transfer by cross-correlated relaxation in solution NMR with very large
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http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--highwire.stanford.edu-icons-externalservices-pubmed-custom-pnas_full_free.gif http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc.gif Related Articles Polarization transfer by cross-correlated relaxation in solution NMR with very large molecules.
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