Related ArticlesImplications of using approximate Bloch-McConnell equations in NMR analyses of chemically exchanging systems: application to the electron self-exchange of plastocyanin.
J Magn Reson. 2003 Aug;163(2):215-27
Authors: Hansen DF, Led JJ
The validity of a series of approximate solutions of the Bloch-McConnell equations normally applied in the analyses of chemically exchanging systems is evaluated, using the electron self-exchange (ESE) in the blue copper protein plastocyanin from Anabaena variabilis as an example. The evaluation is based on a comparison with the results of a complete analysis of the NMR signals of chemically exchanging nuclei that allows an independent and accurate determination of all the involved parameters. The complete analysis is based on the general solution of the Bloch-McConnell equations. It includes a simultaneous analysis of the chemical shift, and the transverse and longitudinal relaxation rates of the observed nuclei as well as the variation of these parameters with the molar fractions of the exchanging species and the rate of the chemical exchange process. The linear prediction model method was used in the data analysis to achieve the highest possible precision. Surprisingly, it is found that the fast exchange condition may not be fulfilled even in cases where a single exchange-averaged NMR signal is observed, and the Larmor frequency and relaxation rates depend linearly on the molar fractions of the exchanging species. In such cases the use of approximate solutions in the analysis of the transverse relaxation rates and the pseudo-contact shifts can lead to erroneous results. In limiting cases close to the fast exchange and slow exchange regimes correct values of some of the parameters can be obtained using the second order approximate solution of the Bloch-McConnell equations. In contrast, the complete analysis of the NMR signals results in an accurate determination of the exchange rates and the NMR parameters of the exchanging sites. This, in turn, can provide information about the structure and function of a protein undergoing chemically exchange. For the investigated plastocyanin the complete analysis results in an accurate determination of the paramagnetic enhancement of the nuclear relaxation rates, the paramagnetic chemical shift, the electron relaxation rate, the electron self-exchange rate, and the distances between the nuclei and the paramagnetic metal ion, viz. the Cu2+ ion.
High-resolution protein structure determination starting with a global fold calculated from exact solutions to the RDC equations
High-resolution protein structure determination starting with a global fold calculated from exact solutions to the RDC equations
Abstract We present a novel structure determination approach that exploits the global orientational restraints from RDCs to resolve ambiguous NOE assignments. Unlike traditional approaches that bootstrap the initial fold from ambiguous NOE assignments, we start by using RDCs to compute accurate secondary structure element (SSE) backbones at the beginning of structure calculation. Our structure determination package, called rdc-Panda (RDC-based SSE PAcking with...
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01-09-2011 12:46 PM
[NMR paper] Purification, crystallization, NMR spectroscopy and biochemical analyses of alpha-phy
Purification, crystallization, NMR spectroscopy and biochemical analyses of alpha-phycoerythrocyanin peptides.
Related Articles Purification, crystallization, NMR spectroscopy and biochemical analyses of alpha-phycoerythrocyanin peptides.
Eur J Biochem. 2002 Oct;269(20):5046-55
Authors: Wiegand G, Parbel A, Seifert MH, Holak TA, Reuter W
The alpha-phycoerythrocyanin subunits of the different phycoerythrocyanin complexes of the phycobilisomes from the cyanobacterium Mastigocladus laminosus perform a remarkable photochemistry. Similar to...
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11-24-2010 08:58 PM
[NMR paper] Design and NMR analyses of compact, independently folded BBA motifs.
Design and NMR analyses of compact, independently folded BBA motifs.
Related Articles Design and NMR analyses of compact, independently folded BBA motifs.
Fold Des. 1998;3(2):95-103
Authors: Struthers M, Ottesen JJ, Imperiali B
BACKGROUND: Small folded polypeptide motifs represented highly simplified systems for theoretical and experimental studies on protein structure and folding. We have recently reported the design and characterization of a metal-ion-independent 23-residue peptide with a beta beta alpha structure (BBA1), based on the zinc...
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11-17-2010 11:06 PM
[NMR paper] NMR analyses of the interactions of human annexin I with ATP, Ca2+, and Mg2+.
NMR analyses of the interactions of human annexin I with ATP, Ca2+, and Mg2+.
Related Articles NMR analyses of the interactions of human annexin I with ATP, Ca2+, and Mg2+.
FEBS Lett. 1998 Apr 3;425(3):523-7
Authors: Han HY, Lee YH, Oh JY, Na DS, Lee BJ
Human annexin I is a member of the annexin family of calcium-dependent phospholipid binding proteins. The structure of an N-terminally truncated human annexin I (delta-annexin I) and its interactions with Ca2+, Mg2+, and ATP were studied at the atomic level using nuclear magnetic resonance...
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NMR analyses of the G{beta}{gamma} binding and conformational rearrangements of the c
NMR analyses of the G{beta}{gamma} binding and conformational rearrangements of the cytoplasmic pore of G protein-activated inwardly rectifying potassium channel 1 (GIRK1).
Related Articles NMR analyses of the G{beta}{gamma} binding and conformational rearrangements of the cytoplasmic pore of G protein-activated inwardly rectifying potassium channel 1 (GIRK1).
J Biol Chem. 2010 Nov 12;
Authors: Yokogawa M, Osawa M, Takeuchi K, Mase Y, Shimada I
G protein-activated inwardly rectifying potassium channel (GIRK) plays crucial roles in regulating heart...
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11-16-2010 04:13 PM
[NMR paper] Structural analyses of CREB-CBP transcriptional activator-coactivator complexes by NM
Structural analyses of CREB-CBP transcriptional activator-coactivator complexes by NMR spectroscopy: implications for mapping the boundaries of structural domains.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Structural analyses of CREB-CBP transcriptional activator-coactivator complexes by NMR spectroscopy: implications for mapping the boundaries of structural domains.
J Mol Biol. 1999 Apr 16;287(5):859-65
Authors: Radhakrishnan I, Pérez-Alvarado GC, Parker D, Dyson HJ,...
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08-21-2010 04:03 PM
NMR Bloch Equation Model
NMR Bloch Equation Model
http://i.ytimg.com/vi/vKW-l6o23Bw/default.jpg
NMR Bloch Equation Model
Simulation of NMR spin system undergoing 90x pulse and recovery
From: jabakdb
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