Wiktor Koźmiński's NMR group

Biological and Chemical Research Centre, University of Warsaw

  • Increase font size
  • Default font size
  • Decrease font size
Wiktor Koźmiński's NMR Group

New Article in Journal of Biomolecular NMR

Print

High-dimensionality 13C direct-detected NMR experiments for the automatic assignment of intrinsically disordered proteins

Wolfgang Bermel, Isabella C. Felli, Leonardo Gonelli, Wiktor Koźmiński, Alessandro Piai, Roberta Pierratelli, Anna Zawadzka-Kazimierczuk


alt

We present three novel exclusively heteronuclear 5D 13C direct-detected NMR experiments, namely (HN-flipN)CONCACON, (HCA)CONCACON and (H)CACON(CA)CON, designed for easy sequence-specific resonance assignment of intrinsically disordered proteins (IDPs). The experiments proposed have been optimized to overcome the drawbacks which may dramatically complicate the characterization of IDPs by NMR, namely the small dispersion of chemical shifts and the fast exchange of the amide protons with the solvent. A fast and reliable automatic assignment of α-synuclein chemical shifts was obtained with the Tool for SMFT-based Assignment of Resonances (TSAR) program based on the information provided by these experiments.

 

New Article in Journal of Biomolecular NMR

Print

4D Non-uniformly sampled C,C-NOESY experiment for sequential assignment of 13C,15N-labeled RNAs

Jan Stanek, Peter Podbevšek, Wiktor Koźmiński, Janez Plavec, Mirko Cevec


alt

A 4D 13C(aromatic),13C(ribose)-edited NOESY experiment is introduced to improve sequential assignment of non-coding RNA, often hampered by a limited dispersion of 1H and 13C chemical shifts. The 13C-labeling of RNA is fully utilized by inclusion of two 13C evolution periods. These dimensions provide enhanced dispersion of resonances in the 4D spectrum. High spectral resolution is obtained using random non-uniform sampling in three indirect dimensions. The autocorrelation peaks are efficiently suppressed using band-selective pulses. Since the dynamic range of observed resonances is significantly decreased, the reconstruction of the 4D spectrum is greatly simplified. The experiment can replace two conventionally sampled 3D NOESY spectra (either ribose-13C- or aromatic-13C-separated), and remove most ambiguities encountered during sequential walks. The assignment strategy based on a homonuclear and 4D C,C-edited NOESY experiments is proposed and verified on a 34-nt RNA showing typical structure elements.

 

New Review in ChemPhysChem

Print

High-Dimensional NMR Spectra for Structural Studies of Biomolecules

Krzysztof Kazimierczuk, Jan Stanek, Anna Zawadzka-Kazimierczuk, Wiktor Koźmiński


alt

Recent developments in the acquisition and processing of NMR data sets facilitate the recording of ultra-high-resolution NMR spectra in a reasonable time. The new experiments allow easy resonance assignment for folded and unfolded proteins, as well as the precise determination of spectral parameters, for example, chemical shifts, NOE contacts, coupling constants or cross-correlated relaxation rates. Owing to exceptional resolution of 4D–6D spectroscopy, detailed studies of biomolecules of unprecedented complexity are now possible. Herein, the principles of acquisition and processing methods are presented. The main applications of high-dimensional NMR experiments, including backbone and side-chain resonance assignment in proteins, as well as heteronuclear edited NOE techniques are reviewed.
 

 

New Article in Journal of Inclusion Phenomena and Macrocyclic Chemistry

Print

Complex formation of fenchone with α-cyclodextrin: NMR titrations

Michał Nowakowski, Andrzej Ejchart


alt

13C NMR titration studies of inclusion complexes of bicyclic terpenoid, fenchone enantiomers with α-cyclodextrin revealed their 1:2 guest–host stoichiometry. Sequential binding constants were determined indicating a strong binding cooperativity of two α-cyclodextrin to fenchone. The overall association constants were used to calculate the Gibbs free energies of diastereomeric complex formation, which might be used as a measure of chiral recognition of fenchone by α-cyclodextrin. These results were compared with corresponding data derived for camphor, which is an isomeric bicyclic terpenoid.

 

New Article in Journal of Biomolecular NMR

Print

Selective diagonal-free 13C,13C-edited aliphatic–aromatic NOESY experiment with non-uniform sampling

Jan Stanek, Michał Nowakowski, Saurabh Saxena, Katarzyna Ruszczyńska-Bartnik, Andrzej Ejchart, Wiktor Koźmiński


alt

A band-selective aromatic–aliphatic C,C-edited four-dimensional NOESY experiment is proposed here. Its key advantage is the absence of auto-correlation signals which makes it very attractive for joint use with non-uniform sampling. It is demonstrated here that the sensitivity of the experiment is not significantly affected by utilization of selective pulses (for either aromatic-13C or aliphatic-13C spins). The method was applied to the sample of E32Q mutant of human S100A1 protein, a homodimer of total molecular mass ~20 kDa. High-resolution 4D spectra were obtained from ~1.5 % of sampling points required conventionally. It is shown that superior resolution facilitates unambiguous assignment of observed aliphatic–aromatic cross-peaks. Additionally, the addition of aliphatic-13C dimension enables to resolve peaks with degenerated aliphatic 1H chemical shifts. All observed cross-peaks were validated against previously determined 3D structure of E32Q mutant of S100A1 protein (PDB 2LHL). The increased reliability of structural constraints obtained from the proposed high-resolution 4D 13C(ali),13C(aro)-edited NOESY can be exploited in the automated protocols of structure determination of proteins.

 

New Article in Protein Science

Print

Protonation-dependent conformational variability of intrinsically disordered proteins

Leonhard Geist, Morkos A. Henen, Sandra Haiderer, Thomas C. Schwarz, Dennis Kurzbach, Anna Zawadzka-Kazimierczuk, Saurabh Saxena, Szymon Żerko, Wiktor Koźmiński, Dariush Hinderberger, Robert Konrat


Intrinsically disordered proteins (IDPs) are characterized by substantial conformational plasticity and undergo rearrangements of the time-averaged conformational ensemble upon changes of environmental conditions (e.g., in ionic strength, pH, molecular crowding). In contrast to stably folded proteins, IDPs often form compact conformations at acidic pH. The biological relevance of this process was, for example, demonstrated by NMR studies of the aggregation prone (low pH) state of α-Synuclein. Here we report a large-scale analysis of the pH dependence of disordered proteins using the recently developed meta-structure approach. The meta-structure analysis of a large set of intrinsically disordered proteins revealed a significant tendency of IDPs to form α-helical secondary structure elements and to preferentially fold into more compact structures under acidic conditions. The predictive validity of this novel approach was demonstrated with applications to the tumor-suppressor BASP1 and the transcription factor Tcf4.

 

New Article in Angewandte Chemie International Edition

Print

Probing Local Backbone Geometries in Intrinsically Disordered Proteins by Cross-Correlated NMR Relaxation

Jan Stanek, Saurabh Saxena, Leonhard Geist, Robert Konrat, Wiktor Koźmiński


alt

An ultra-high-resolution NMR experiment for the measurement of intraresidue 1H(i)–15N(i)–13C'(i) dipolar–chemical shift anisotropy relaxation interference is employed to extract information about local backbone geometries in intrinsically disordered proteins. The study of tumor suppressor BASP1 revealed a population shift of β-turn geometries at low pH conditions and a compaction of the BASP1 structural ensemble.

 

New Article in Polyhedron

Print

Sialorphin and its analog as ligands for copper(II) ions

Elżbieta Kamysz, Aleksandra Kotynia, Żaneta Czyżnikowska, Mariusz Jaremko, Łukasz Jaremko, Michał Nowakowski, Justyna Brasun


alt

In this study the sialorphin (Gln-His-Asn-Pro-Arg) and its analog (Glp-His-Asn-Pro-Arg) were analyzed in terms of metal binding ability. Both peptides were synthesized using the solid-phase method. The application of number analytical methods: potentiometry, spectroscopy (UV–Vis, CD, NMR) and mass spectrometry allowed for a detailed characterization of the coordination abilities of presented peptides. The analysis of the obtained results has shown that both peptides are able to form a series of complexes. However due to the presence of free N-terminal amino group the sialorphin is more effective in metal ion binding. Nevertheless, in basic conditions both peptides involve the amide nitrogen belonging to the side chain of Asn3 moiety and form 4N complex with square planar structure. This unusual ability has been confirmed by the results obtained from the NMR studies.

 


Page 4 of 5






Banner
Banner
Banner

Conferences organized

by us:


 

euromar 2017 logo

 


 

mmcebanner3

 


 

AUM4

 


We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set.

I accept cookies from this site.