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[NMR paper] Partial solid-state NMR 1H, 13C, 15N resonance assignments of a perdeuterated back-exchanged seven-transmembrane helical protein Anabaena Sensory Rhodopsin.
Mar 26, 2018 - 2:55 AM - by nmrlearner
nmrlearner's Avatar Partial solid-state NMR 1H, 13C, 15N resonance assignments of a perdeuterated back-exchanged seven-transmembrane helical protein Anabaena Sensory Rhodopsin.

Partial solid-state NMR 1H, 13C, 15N resonance assignments of a perdeuterated back-exchanged seven-transmembrane helical protein Anabaena Sensory Rhodopsin.

Biomol NMR Assign. 2018 Mar 23;:

Authors: Bolton D, Brown LS, Ladizhansky V

Abstract
Anabaena Sensory Rhodopsin (ASR) is a unique photochromic membrane-embedded photosensor which interacts with soluble transducer and is likely involved in a light-dependent gene regulation in the cyanobacterium Anabaena sp. PCC 7120. We report partial spectroscopic 1H, 13C and 15N assignments of perdeuterated and back-exchanged ASR reconstituted in lipids. The reported assignments are in general agreement with previously determined assignments of carbon and nitrogen resonances in fully protonated samples. Because the back-exchange was performed on ASR in a detergent-solubilized state, the location of detected residues reports on the solvent accessibility of ASR in detergent. A comparison with the results of previously published hydrogen/exchange data collected on the ASR reconstituted in lipids, suggests that the protein has larger solvent accessible surface in the detergent-solubilized state.


PMID: 29572785 [PubMed - as supplied by publisher]



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0 Replies | 59 Views
[NMR paper] NMR assignment and solution structure of the external DII domain of the yeast Rvb2 protein.
Mar 24, 2018 - 12:21 PM - by nmrlearner
nmrlearner's Avatar NMR assignment and solution structure of the external DII domain of the yeast Rvb2 protein.

NMR assignment and solution structure of the external DII domain of the yeast Rvb2 protein.

Biomol NMR Assign. 2018 Mar 22;:

Authors: Bragantini B, Rouillon C, Charpentier B, Manival X, Quinternet M

Abstract
We report the nearly complete 1H, 15N and 13C resonance assignment and the solution structure of the external DII domain of the yeast Rvb2 protein, a member of the AAA+ATPase superfamily.


PMID: 29569106 [PubMed - as supplied by publisher]



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0 Replies | 65 Views
[NMR paper] The NMR contribution to protein-protein networking in Fe-S protein maturation.
Mar 24, 2018 - 12:21 PM - by nmrlearner
nmrlearner's Avatar The NMR contribution to protein-protein networking in Fe-S protein maturation.

The NMR contribution to protein-protein networking in Fe-S protein maturation.

J Biol Inorg Chem. 2018 Mar 22;:

Authors: Banci L, Camponeschi F, Ciofi-Baffoni S, Piccioli M

Abstract
Iron-sulfur proteins were among the first class of metalloproteins that were actively studied using NMR spectroscopy tailored to paramagnetic systems. The hyperfine shifts, their temperature dependencies and the relaxation rates of nuclei of cluster-bound residues are an efficient fingerprint of the nature and the oxidation state of the Fe-S cluster. NMR significantly contributed to the analysis of the magnetic coupling patterns and to the understanding of the electronic structure occurring in [2Fe-2S], [3Fe-4S] and [4Fe-4S] clusters bound to proteins. After the first NMR structure of a paramagnetic protein was obtained for the reduced E. halophila HiPIP I, many NMR structures were determined for several Fe-S proteins in different oxidation states. It was found that differences in chemical shifts, in patterns of unobserved residues, in internal mobility and in thermodynamic stability are suitable data to map subtle changes between the two different oxidation states of the protein. Recently, the interaction networks responsible for maturing human mitochondrial and cytosolic Fe-S proteins have been largely characterized by combining solution NMR standard experiments with those tailored to paramagnetic systems. We show here the contribution of solution NMR in providing a detailed molecular view of "Fe-S interactomics". This contribution was particularly effective when protein-protein... [Read More]
0 Replies | 71 Views
[NMR paper] Nanomolar small-molecule detection using a genetically encoded 129Xe NMR contrast agent.
Mar 24, 2018 - 12:21 PM - by nmrlearner
nmrlearner's Avatar Nanomolar small-molecule detection using a genetically encoded 129Xe NMR contrast agent.

Nanomolar small-molecule detection using a genetically encoded 129Xe NMR contrast agent.

Chem Sci. 2017 Nov 01;8(11):7631-7636

Authors: Roose BW, Zemerov SD, Dmochowski IJ

Abstract
Genetically encoded magnetic resonance imaging (MRI) contrast agents enable non-invasive detection of specific biomarkers in vivo. Here, we employed the hyper-CEST 129Xe NMR technique to quantify maltose (32 nM to 1 mM) through its modulation of conformational change and xenon exchange in maltose binding protein (MBP). Remarkably, no hyper-CEST signal was observed for MBP in the absence of maltose, making MBP an ultrasensitive "smart" contrast agent. The resonance frequency of 129Xe bound to MBP was greatly downfield-shifted (?? = 95 ppm) from the 129Xe(aq) peak, which facilitated detection in E. coli as well as multiplexing with TEM-1 ?-lactamase. Finally, a Val to Ala mutation at the MBP-Xe binding site yielded 34% more contrast than WT, with 129Xe resonance frequency shifted 59 ppm upfield from WT. We conclude that engineered MBPs constitute a new class of genetically encoded, analyte-sensitive molecular imaging agents detectable by 129Xe NMR/MRI.


PMID: 29568427 [PubMed]



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Direct hyperpolarization of micro- and nanodiamonds for bioimaging applications - Considerations on particle size, functionalization and polarization loss
Mar 24, 2018 - 12:19 AM - by nmrlearner
nmrlearner's Avatar From The DNP-NMR Blog:

Direct hyperpolarization of micro- and nanodiamonds for bioimaging applications - Considerations on particle size, functionalization and polarization loss

Kwiatkowski, G., et al., Direct hyperpolarization of micro- and nanodiamonds for bioimaging applications - Considerations on particle size, functionalization and polarization loss. J Magn Reson, 2018. 286: p. 42-51.


https://www.ncbi.nlm.nih.gov/pubmed/29183003


Due to the inherently long relaxation time of (13)C spins in diamond, the nuclear polarization enhancement obtained with dynamic nuclear polarization can be preserved for a time on the order of about one hour, opening up an opportunity to use diamonds as a new class of long-lived contrast agents. The present communication explores the feasibility of using (13)C spins in directly hyperpolarized diamonds for MR imaging including considerations for potential in vivo applications.


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[NMR paper] Trimethylsilyl tag for probing protein-ligand interactions by NMR.
Mar 23, 2018 - 11:18 AM - by nmrlearner
nmrlearner's Avatar Trimethylsilyl tag for probing protein-ligand interactions by NMR.

Trimethylsilyl tag for probing protein-ligand interactions by NMR.

J Biomol NMR. 2018 Mar 21;:

Authors: Becker W, Adams LA, Graham B, Wagner GE, Zangger K, Otting G, Nitsche C

Abstract
Protein-ligand titrations can readily be monitored with a trimethylsilyl (TMS) tag. Owing to the intensity, narrow line shape and unique chemical shift of a TMS group, dissociation constants can be determined from straightforward 1D 1H-NMR spectra not only in the fast but also in the slow exchange limit. The tag is easily attached to cysteine residues and a sensitive reporter of ligand binding also at sites where it does not interfere with ligand binding or catalytic efficiency of the target protein. Its utility is demonstrated for the Zika virus NS2B-NS3 protease and the human prolyl isomerase FK506 binding protein.


PMID: 29564580 [PubMed - as supplied by publisher]



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0 Replies | 60 Views
[NMR paper] Solid-state NMR at natural isotopic abundance for the determination of conformational polymorphism - the case of designed ?-turn peptides containing di-prolines.
Mar 23, 2018 - 11:18 AM - by nmrlearner
nmrlearner's Avatar Solid-state NMR at natural isotopic abundance for the determination of conformational polymorphism - the case of designed ?-turn peptides containing di-prolines.

Related Articles Solid-state NMR at natural isotopic abundance for the determination of conformational polymorphism - the case of designed ?-turn peptides containing di-prolines.

Chem Commun (Camb). 2017 Jan 19;53(7):1317-1320

Authors: Yarava JR, Sonti R, Kantharaju K, Raghothama S, Ramanathan KV

Abstract
The proton double quantum-carbon single quantum correlation experiment has been applied to designed peptides in the solid state in natural isotopic abundance. Analogous to nOe studies in solution, through-space double-quantum connectivities have been exploited to obtain the cis-trans conformational polymorphism of diproline residues occurring at ?-turns in the peptides.


PMID: 28074945 [PubMed - indexed for MEDLINE]



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0 Replies | 56 Views
[NMR paper] Compact, hydrophilic, lanthanide-binding tags for paramagnetic NMR spectroscopy.
Mar 23, 2018 - 11:18 AM - by nmrlearner
nmrlearner's Avatar Compact, hydrophilic, lanthanide-binding tags for paramagnetic NMR spectroscopy.

Compact, hydrophilic, lanthanide-binding tags for paramagnetic NMR spectroscopy.

Chem Sci. 2015 Apr 01;6(4):2614-2624

Authors: Lee MD, Loh CT, Shin J, Chhabra S, Dennis ML, Otting G, Swarbrick JD, Graham B

Abstract
The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported. Each tag is based on the ((2S,2'S,2''S,2'''S)-1,1',1'',1'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(propan-2-ol)) scaffold, featuring small chiral alcohol coordinating pendants to minimise the size and hydrophobic character of each tag. The tags feature different linkers of variable length for conjugation to protein via a single cysteine residue. Each tag's ability to induce pseudocontact shifts (PCS) was assessed on a ubiquitin A28C mutant. Two enantiomeric tags of particular note, C7 and C8, produced significantly larger ??-tensors compared to a previously developed tag, C1, attributed to the extremely short linker utilised, limiting the mobility of the bound lanthanide ion. The C7 and C8 tags' capacity to induce PCSs was further demonstrated on GB1 Q32C and 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) S112C/C80A mutants. Whilst factors such as the choice of lanthanide ion, pH and site of conjugation influence the size of the PCSs obtained, the tags represent a significant advance in the field.


PMID: 29560247 [PubMed]



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0 Replies | 68 Views
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