Cryoprobe: a key tool for the NMR Characterization of small amount of peptides

Posted on 2012/04/29 by Pau

“Fast cysteine labelling of peptides promoted by an adjacent arginine has been observed with a standard labelling agent specific for amines, N-succinimidyl 4-[18F]fluorobenzoate” Sergio Abad, Pau Nolis, Juan D. Gispert, Jan Spengler, Fernando Albericio, Santiago Rojasac and José R. Herance, ChemComm, ACCEPTED 2012 DOI: 10.1039/C2CC32095A

Fast cysteine labelling of peptides promoted by an adjacent arginine has been observed with a standard labelling agent specific for amines, N-succinimidyl 4-[18F]fluorobenzoate. HMBC experiment was the key experiment to corroborate this treat. The small amounts of some peptides herein studied required the sensitivty beneffits of a 500 MHz equipped with TCI cryprobe.

Measurement of the magnitude and the sign of small nJ(CH) on protonated and non-protonated carbons

Posted on 2012/03/26 by Josep

“A definitive NMR solution for the simple and accurate measurement of the magnitude and the sign of small heteronuclear coupling constants on protonated and non-protonated carbons”, by Josep Saurí, Juan Félix Espinosa and Teodor Parella; Angew. Chem. Int. Ed. (2012) DOI: 10.1002/anie.201108959

The measurement of long-range proton carbon coupling constants in natural-abundance molecules has always been a tranding topic for the NMR community. Despite the extensive number of NMR techniques that have been developed, there are still remain two unsolved problems pertaining to non-protonated carbons, namely, a) and accurate measurement of very small coupling constants (less than 2-3 Hz) , and b) the absence of a general and robust approach to determine the sign of the coupling. All these annoying drawbacks can be solved using the new selHSQMBC-TOCSY experiment. The method combines in a single pulse scheme all the benefits known for the widely used HSQMBC and HSQC-TOCSY experiments. Thus, the experiment is able to measuring the magnitude and the sign of ⁿJ_CH (n>1) with excellent accuracy and great simplicity by analyzing the relative sense of the displacement of IPAP multiplets in the direct dimension, showing particular interest to the application on quaternary carbons.

Pulse Program Code for Bruker: selHSQMBC-TOCSY

8th Workshop on Magnetic Resonance Spectroscopy and Imaging (MRS/MRI) Applied to Laboratory Animals

Posted on 2012/03/07 by Silvia

Dates: 4^th -7^th June 2012

Organized by the SeRMN of the Autonomous University of Barcelona (UAB).

This course combines a comprehensive series of lectures on the technology of magnetic resonance spectroscopy and imaging (MRS/MRI) with hands-on laboratory sessions to provide practical demonstrations of key concepts and procedures for preclinical studies.

Whether you are considering MRI as a research tool in your lab or just would like to learn more about MRI, this workshop addresses practical aspects of experimental MRI with laboratory animals and provide valuable hands-on experience on a 7 Tesla Bruker BioSpec spectrometer.

Number of participants will be limited to 4.

For the registration, please fill the Registration Form and email it to silvia.lope@uab.es, registration deadline ends May 21^st.

See Workshop Brochure for more information or contact Dr. Silvia Lope via email.

HPLC-DAD-(SPE)-NMR/MS II: fundamentals and working modes

Posted on 2012/03/05 by Miriam

This hyphenated technique combines HPLC with three complementary detection techniques – NMR Spectroscopy, Mass Spectrometry and Diode Array Detection. It is a highly rich information source, which can be obtained by one-shot analysis.

There are three different modes of work: Flow-NMR, Stop-Flow and SPE-storage; and depending on the scientific problem one or another will be the most adequate. The fundamentals of the technique / working modes are shown in the figure.

The possibility of a post-chromatography storage/concentration of the peaks of interest of the chromatogram, using a SPE (Solid Phase Extraction) system, together with the use of cool probes, increases the sensitivity of the NMR detection, making possible the acquisition of 2D NMR experiments and work with heteronuclei.

CHIRAL METABONOMICS: Giving Metabonomics a Chiral Dimension

Posted on 2012/02/20 by Miriam

“Chiral Metabonomics: 1H NMR-Based Enantiospecific Differentiation of Metabolites in Human Urine via Direct Cosolvation with β-Cyclodextrin”

Míriam Pérez-Trujillo, John C. Lindon, Teodor Parella, Hector C. Keun, Jeremy K. Nicholson and Toby J. Athersuch. Analytical Chemistry, February 2012 DOI:10.1021/ac203291d

Differences in molecular chirality remain an important issue in drug metabolism and pharmacokinetics for the pharmaceutical industry and regulatory authorities and chirality is an important feature of many endogenous metabolites. We present a 1H NMR-based method for the rapid, direct differentiation and identification of chiral drug enantiomers in human urine without pre-treatment of any kind. This approach is simple, rapid, robust, and involves minimal sample manipulation; it avoids labor-intensive steps such as derivatization or purification of the chiral compounds. Moreover, the versatility of NMR spectroscopy allows, after addition of an appropriate CSA, the simultaneous characterization of drug metabolites, both expected and unexpected. From these initial findings we propose that more extensive and detailed enantiospecific metabolic profiling could be possible using CSA-NMR spectroscopy than has been previously reported.

HPLC-DAD-(SPE)-NMR/MS I: all in one technique for the analysis of mixtures

Posted on 2012/02/14 by Miriam

The combination of liquid chromatography with three complementary detection techniques – NMR Spectroscopy, Mass Spectrometry and Diode Array Detection, provides highly rich information in a one-shot analysis.

The possibility of a post-chromatography storage /concentration of the chromatographic peaks of interest, using a SPE (Solid Phase Extraction) system, together with the use of cool probes, increases the sensitivity of the NMR detection.

There are different modes of work: Flow- NMR, Stop-Flow and SPE-storage, being one or another most adequate depending on the scientific problem (see HPLC-DAD-(SPE)-NMR/MS II: fundamentals and working modes).

The fields of application are very broad, including food chemistry, natural products analysis, elucidation of impurities, characterisation of metabolites and xenobiotics, etc.

2012 NMR Events

Posted on 2012/02/05 by Miquel

This is a non-exhaustive list of NMR related events taking place in 2012:

12-13 March – Bio-NMR Meeting, Barcelona, Spain
15-20 April – 53rd ENC, Miami, FL, USA
5-11 May – 20th ISMRM Meeting & Exhibition, Melbourne, Australia
26-29 June – 11th International Conference on Magnetic Resonance in Food, Wageningen, NL
1-5 July – EUROMAR 2012, University College, Dublin, Ireland
29 July-3 August – Gordon Research Conference: In Vivo Magnetic Resonance, Waterville, ME, USA
19-24 August – 25th ICMRBS – MR in Biological Systems, Lyon, France
5-8 September – 2012 World Molecular Imaging Congress, Dublin, Ireland
4-9 September – 37th FEBS Congress, Seville, Spain
9-12 September – SMASH 2012, Providence, RI, USA
25 – 28 September - IV Ibero-American NMR Meeting, Aveiro, Portugal
4-6 October – 29th ESMRMB Congress, Lisbon, Portugal

For more thorough lists of events, check these sites:

Forthcoming MR Events at Stan’s site
Upcoming NMR Events and Conferences at Canada’s Field NMR Facility for Solids
NMR Events, MRI Events and Users’ Meetings at Bruker BioSpin web site.

HR-MAS: a key technique to study Nanoparticles

Posted on 2012/01/26 by Pau

“Phosphine Stabilized Ruthenium Nanoparticles: the Effect of the Nature of the Ligand in Catalysis” David González-Gálvez, Pau Nolis, Karine Philippot, Bruno Chaudret and Piet W. N. M. van Leeuwen. ACS Catalysis, January 2012 DOI: 10.1021/cs200633k

Various ligands not forming monometallic complexes were used for Ru nanoparticle stabilization, enabling the control of size, shape and electronic properties. HRMAS NMR spectroscopy allowed us to study surface-bound molecules, evidencing ligand hydrogenation and decomposition of THF during the RuNP synthesis. Catalysis studies underscore the importance of the nature of the ligands. The RuNPs were tested in the hydrogenation of aromatics, showing very high activities (TOF > 60,000 h–1, 40 bar, 393K). A pronounced ligand effect was found and dialkylaryl phosphine ligands gave the fastest catalyst.

Myo-inositol and glycine relative content may help to grade astrocytic tumours.

Posted on 2012/01/16 by Miquel

“Non-Invasive grading of astrocytic tumours from the relative contents of myo-inositol and glycine measured by in vivo MRS”, Ana Paula Candiota, Carles Majós, Margarida Julià-Sapé, Miquel Cabañas, Juan José Acebes, Àngel Moreno-Torres, John R. Griffiths, Carles Arús; Journal Belge de Radiologie – Belgisch Tijdschrift voor Radiologie, 94, 319-329 (2011). (PDF file)

MRI and MRS are established methodologies for evaluating intracranial lesions. One MR spectral feature suggested for in vivo grading of astrocytic tumours is the apparent myo-Inositol (mI) intensity (ca 3.55ppm) at short echo times, although glycine (gly) may also contribute in vivo to this resonance. The purpose of this study was to quantitatively evaluate the mI + gly contribution to the recorded spectral pattern in vivo and correlate it with in vitro data obtained from perchloric acid extraction of tumour biopsies. Patient spectra (n = 95) at 1.5T at short (20-31 ms) and long (135-136 ms) echo times were obtained from the INTERPRET MRS database (http://gabrmn.uab.es/interpretvalidateddb/). Phantom spectra were acquired with a comparable protocol. Spectra were automatically processed and the ratios of the (mI + gly) to Cr peak heights ((mI + gly)/Cr) calculated. Perchloric acid extracts of brain tumour biopsies were analysed by high-resolution NMR at 9.4T. The ratio (mI + gly)/Cr decreased significantly with astrocytic grade in vivo between low-grade astrocytoma (A2) and glioblastoma multiforme (GBM). In vitro results displayed a somewhat different tendency, with anaplastic astrocytomas having significantly higher (mI + gly)/Cr than A2 and GBM. The discrepancy between in vivo and in vitro data suggests that the NMR visibility of glycine in glial brain tumours is restricted in vivo.

Low-grade astrocytomas (top row, A2) could be distinguished from glioblastomas (bottom row, GBM) by using the relative visibility of myo-inositol and glycine at short and long echo times (LTE vs STE) NMR spectra.

Neurodegeneration in NPC Mice by T2 and DTI MRI

Posted on 2011/11/22 by Silvia

“In Vivo Assessment of Neurodegeneration in Niemann-Pick Type C Mice by Quantitative T2 Mapping and Diffusion Tensor Imaging”, by John W. Totenhagen, Silvia Lope-Piedrafita, Ivan A. Borbon, Eriko S. Yoshimaru, Robert P. Erickson, and Theodore P. Trouard; Journal of Magnetic Resonance Imaging, November 2011.
doi: 10.1002/jmri.22837

NIEMANN-PICK TYPE C (NPC) disease is a rare genetic neurodegenerative disease with no cure and few effective options for treatment. Diagnosis is most often made during childhood with symptoms progressively worsening and leading to death prior to adulthood. The purpose of this work was to quantitatively and noninvasively assess neurological disease progression in a mouse model of NPC disease by measuring white matter status with magnetic resonance imaging (MRI) techniques of T2 mapping and diffusion tensor imaging (DTI) at multiple timepoints. The parameters obtained from these measurements were compared to histological measures of myelination. The findings of this study suggest that quantitative MRI measurements may be useful in vivo biomarkers for future studies of disease progression and proposed treatments in NPC disease models.

SeRMN – UAB Blog

Research & development, training, and facility management at the SeRMN.