caa a22 4500 445325925 CHVBK 20180317142720.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s10858-011-9520-6 doi (NATIONALLICENCE)springer-10.1007/s10858-011-9520-6 Quantifying millisecond time-scale exchange in proteins by CPMG relaxation dispersion NMR spectroscopy of side-chain carbonyl groups [Elektronische Daten] [Alexandar Hansen, Lewis Kay] A new pulse sequence is presented for the measurement of relaxation dispersion profiles quantifying millisecond time-scale exchange dynamics of side-chain carbonyl groups in uniformly 13C labeled proteins. The methodology has been tested using the 87-residue colicin E7 immunity protein, Im7, which is known to fold via a partially structured low populated intermediate that interconverts with the folded, ground state on the millisecond time-scale. Comparison of exchange parameters extracted for this folding ‘reaction' using the present methodology with those obtained from more ‘traditional' 15N and backbone carbonyl probes establishes the utility of the approach. The extracted excited state side-chain carbonyl chemical shifts indicate that the Asx/Glx side-chains are predominantly unstructured in the Im7 folding intermediate. However, several crucial salt-bridges that exist in the native structure appear to be already formed in the excited state, either in part or in full. This information, in concert with that obtained from existing backbone and side-chain methyl relaxation dispersion experiments, will ultimately facilitate a detailed description of the structure of the Im7 folding intermediate. Springer Science+Business Media B.V., 2011 CPMG nationallicence Relaxation dispersion nationallicence Im7 nationallicence Side-chain carbonyl groups nationallicence Excited protein states nationallicence Hansen Alexandar Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, M5S 1A8, Toronto, ON, Canada aut Kay Lewis Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, M5S 1A8, Toronto, ON, Canada aut Journal of Biomolecular NMR Springer Netherlands 50/4(2011-08-01), 347-355 0925-2738 50:4<347 2011 50 10858 https://doi.org/10.1007/s10858-011-9520-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10858-011-9520-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hansen Alexandar Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, M5S 1A8, Toronto, ON, Canada aut NATIONALLICENCE 700 1- Kay Lewis Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, M5S 1A8, Toronto, ON, Canada aut NATIONALLICENCE 773 0- Journal of Biomolecular NMR Springer Netherlands 50/4(2011-08-01), 347-355 0925-2738 50:4<347 2011 50 10858 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer