hcch_tocsy.m
HCCH-TOCSY pulse sequence from Figure 7.28 of Protein NMR Spectroscopy (2nd edition) using the bidirectional propagation method described in (http://dx.doi.org/10.1016/j.jmr.2014.04.002). The sequence is hard-wired to work on 1H,13C proteins and uses PDB labels to select spins that will be affected by otherwise ideal pulses. F1 is 1H, F2 is C, F3 is H.
Syntax
fid=hcch_tocsy(spin_system,parameters,H,R,K)
Arguments
parameters.npoints - a vector of three integers giving the
number of points in the three temporal
dimensions, ordered as [t1 t2 t3]
parameters.sweep - a vector of three real numbers giving
the sweep widths in the three frequen-
cy dimensions, ordered as [f1 f2 f3]
parameters.J_ch - 1H-13C J-coupling in Hz to be used for
magnetisation transfer, typically 140
parameters.delta - coherence transfer evolution delay in
seconds, see the pulse sequence diag-
ram, typically 1.1e-3
parameters.lamp - 1H-13C spin-lock amplitude in Hz, ty-
pically 10000
parameters.sl_tmix - spin-lock mixing time, typically 2e-3
seconds
parameters.dipsi_dur - DIPSI period duration, typically
22.5e-3 seconds
parameters.decouple_f3 - list of spins to be decoupled during
the detection period, typically {'13C'}
H - Hamiltonian matrix, received from context function
R - relaxation superoperator, received from context function
K - kinetics superoperator, received from context function
Outputs
fid - three-dimensional free induction decay
Note: spin labels must be set to PDB atom IDs ('CA', 'HA', etc.) in
sys.labels for this sequence to work properly.
TODO: whoever understands how phase cycles and quadratures work in
3D NMR is welcome to add a phase-sensitive version.
m.walker@soton.ac.uk ilya.kuprov@weizmann.ac.il
Examples
Below is the output of examples/nmr_proteins/hcch_tocsy_gb1.m example file.
Notes
Spin labels must be set to PDB atom IDs ('CA', 'HA', etc.) in sys.labels for this sequence to work properly.
See also
Version 2.5, authors: Matt Walker, Ilya Kuprov
