Chemistry Reference
In-Depth Information
Recent Developments in
15
N NMR Relaxation
Studies that Probe Protein Backbone Dynamics
Rieko Ishima
Abstract Nuclear Magnetic Resonance (NMR) relaxation is a powerful technique
that provides information about internal dynamics associated with configurational
energetics in proteins, as well as site-specific information involved in conforma-
tional equilibria. In particular,
15
N relaxation is a useful probe to characterize
overall and internal backbone dynamics of proteins because the relaxation mainly
reflects reorientational motion of the N-H bond vector. Over the past 20 years,
experiments and protocols for analysis of
15
N
R
1
,
R
2
, and the heteronuclear
15
N-{
1
H} NOE data have been well established. The development of these methods
has kept pace with the increase in the available static-magnetic field strength,
providing dynamic parameters optimized from data fitting at multiple field
strengths. Using these methodological advances, correlation times for global tum-
bling and order parameters and correlation times for internal motions of many
proteins have been determined. More recently, transverse relaxation dispersion
experiments have extended the range of NMR relaxation studies to the milli- to
microsecond time scale, and have provided quantitative information about func-
tional conformational exchange in proteins. Here, we present an overview of recent
advances in
15
N relaxation experiments to characterize protein backbone dynamics.
Keywords Dispersion
Dynamics
NMR
Protein
Relaxation
Contents
1 NMR Relaxation to Detect Protein Dynamics ............................................. 100
2 Recent Improvements in the
15
N
R
1
,
R
2
, and
15
N-{
1
H} NOE Experiments . . ........... 100
2.1 Practical Aspects in
15
N
R
2
Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
2.2 Practical Aspects in
15
N
R
1
Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
2.3 Practical Aspects in
15
N-{
1
H} NOE Experiment . .................................. 106
