13C-13C NOESY: an attractive alternative for studying large macromolecules.
13C direct detection provides a valuable alternative to 1H detection to overcome fast relaxation because of its smaller magnetic moment. 13C-13C NOESY spectra were acquired for a dimeric protein of molecular mass 32 000 and for a monomeric analogue. With increasing molecular mass, the quality of 13C-13C NOESY spectra improves while the scalar-based experiments become less sensitive, as predicted by the increase in the molecular mass. 13C-13C NOESY spectra of the dimer were acquired with different mixing times. The mixing time can be tuned to detect mainly one-bond correlations, or it can be increased to also detect correlations between nuclei at longer distances. It is proposed that 13C-13C dipolar-based experiments provide a promising tool for signal detection and assignment in large macromolecules, such as multimeric species and macromolecular complexes, for which scalar-based experiments become less effective.
Bertini
Ivano
I
CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy. bertini@cerm.unifi.it
Felli
Isabella C
IC
Kümmerle
Rainer
R
Moskau
Detlef
D
Pierattelli
Roberta
R
D002247:Carbon Isotopes; D046911:Macromolecular Substances; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D013482:Superoxide Dismutase / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
D002247:Carbon Isotopes; D046911:Macromolecular Substances; D013482:Superoxide Dismutase; D015032:Zinc