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Improved method for unambiguous amino acid side-chain 1H and 13C resonance assignment
Frank Löhr1, Marco Betz, Heinz Rüterjans
1Institut für Biophysikalische Chemie, Zentrum für Biomolekulare Magnetische Resonanz, Johann Wolfgang Goethe-Universität, Marie Curie-Strasse 9, D-60439 Frankfurt am Main, Germany. murph@bpc.uni-frankfurt.de
Magnetic Resonance in Chemistry : MRC
|February 19, 2004
Summary
This study introduces a new 4D pulse sequence for protein resonance assignment. The H(C)C-COSY-TOCSY-(CACO)NH method simplifies aliphatic side-chain assignments, even with overlapping signals.
Area of Science:
- Biochemistry
- Structural Biology
- Nuclear Magnetic Resonance (NMR) Spectroscopy
Background:
- Protein resonance assignment typically requires multiple multi-dimensional NMR experiments.
- Spectral crowding in NMR spectra complicates the assignment of aliphatic side-chain resonances.
Purpose of the Study:
- To present a novel four-dimensional pulse sequence for complete aliphatic side-chain resonance assignment in proteins.
- To improve the distinction of signals from overlapping side-chains in NMR spectra.
Main Methods:
- Development and application of a four-dimensional pulse sequence: H(C)C-COSY-TOCSY-(CACO)NH.
- Utilizing backbone amide proton (1H) and nitrogen-15 (15N) signal dispersion to alleviate spectral crowding.
- Testing the method on proteins with molecular masses of 11 and 23 kDa.
Main Results:
- The H(C)C-COSY-TOCSY-(CACO)NH sequence provides necessary information for complete aliphatic side-chain resonance assignments.
- The method effectively distinguishes signals from different side-chains, even when spectral overlap occurs in the 1H(N)-15N plane.
- Successful application demonstrated on two proteins of varying sizes.
Conclusions:
- The novel four-dimensional pulse sequence offers an efficient approach for protein side-chain NMR assignment.
- This method enhances spectral resolution and simplifies the assignment process, particularly in cases of spectral overlap.
- The technique is applicable to proteins of moderate molecular weight.