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Anisotropic Parameters in Liquid State NMR

Gel

An important application of high resolution NMR spectroscopy is the structure determination of organic molecules in solution, i.e. constitution, configuration and conformation. A number of sophisticated methods based on classical NMR parameters like chemical shifts, J-couplings and nuclear Overhauser enhancement (NOE) has been developed to accomplish this tasks. The approach has been successfully applied to a vast number of molecules including biomacromolecules and natural and synthetic products. A drawback of these standard NMR parameters is their short range.

The free molecular tumbling in solution effectively averages all anisotropic parameters to zero. If partial alignment is introduced full averaging cannot take place and some residual anisotropic parameters can be detected. The most widely used are the so called Residual Dipolar Couplings (RDCs). They depend on the distance between interacting nuclei and on the angle between internuclear vector and external magnetic field. Thus, RDCs contain structural information about the molecule in a wider range. Our work is focused on development of gels suitable for alignment media and the structure evaluation with the measured RDCs. ...  See more.

Contact B. Luy.


Optimal Control Theory for Optimizing NMR Experiments

OCT

Optimal Control Theory and the GRAPE algorithm derived from is an efficient method to optimize pulse sequences consisting of hundreds or thousands of parameters. This allows implementing all kinds of spin manipulations, provided they are physically possible. Optimal Control Theory has allowed us to develop pulses that achieve e.g. uniform excitation or inversion over a large chemical shift bandwidth, but also band-selective pulses like pulses with compensation of B1 inhomogeneity, pulses leaving magnetization in defined states or optimized transfer elements. Application of the Optimum Control Theory allows creation of pulses with stunning properties. The picture shows simulated excitation profile of one of such pulses (for animation, please click on the picture).  ...  See more.

Contact B.Luy.


Pulse Sequence Development

Pulse Programming

Development of novel and optimization of existing NMR pulse sequences which in general allow a faster and more accurate determination of NMR parameters which are obtained from the different kinds of spectra.  ...  See more.

Contact B. Luy.


Computational Chemistry

Logo Computational Chemistry

The measured experimental anisotropic parameters contain valuable structural information, which can be used to access various aspects of the assignment of the constitution, configuration, conformation and enantiomeric excess of the organic molecules. A more or less trivial case for the use of the anisotropic parameters is the class of rigid molecules. However, the majority of organic molecules with potential applicability in biological systems contain different degree of flexibility, which fails to be analysed with the static models.

Time averaged molecular dynamics simulations with orientational constraints (MDOC), as implemented in the program COSMOS, can be applied for both classes of organic molecules. The current implementation of the program has been tested for the use of residual dipolar couplings (RDCs). Potentially it allows the use of scalar couplings and NOE distances as constraints during the molecular dynamics run. ...  See more.

Contact P. Tzvetkova.


Metabolomics

Metabolomics

Small molecules called metabolites are products of cellular biochemical processes that are found in organisms and body fluids. Metabolomics deals with their systematic investigation. The metabolome is regarded as a chemical fingerprint of the organism. We study with NMR spectroscopy if variations in the metabolome can be exploited as diagnostic tool for disease recognition. Another application of metabolomics is the elucidation of the effect that mutations and/or chemicals have on the organism. Analysis of whole extracts can also be used e.g. in fruit analysis to monitor product quality.  ...  See more.

Contact C. Muhle-Goll.


Structural Biology

Structure

We study by NMR spectroscopy how protein function is related to structure. Apart from structure determination we study in close collaboration with biological groups e.g. at the ITG  how mutations affect the structural integrity of the protein or the interaction with ligands. Another topic is the identification and analysis of natural compounds isolated from microorganisms in collaboration with TEBI and IFG or of peptide mimetica potentially useful in therapeutics. We additionally employ a diverse range of biochemical, biomolecular and bioinformatics techniques to develop a comprehensive understanding of the studied systems. ...  See more.

Contact C. Muhle-Goll.


Pro²NMR

Pro2NMR

NMR activites concerning product and process characterisation via diverse NMR modalities are summarised in the instrumental facility Pro2NMR at KIT and RWTH Aachen. Most often, questions in the context of research in engineering are addressed, for example via diffusometry, relaxometry, spectroscopy and NMR imaging. Special emphasis is put onto process analytics and product characterization for structural and molecular investigations in chemistry, bio- and chemical engeneering.  ...  See more.

Contact G. Guthausen.