hnco.m

Phase-sensitive HNCO pulse sequence from

            http://dx.doi.org/10.1016/0022-2364(90)90333-5

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, 15N proteins and uses PDB labels to select spins that will be affected by otherwise ideal pulses. F1 is N, F2 is CO, F3 is H.

Syntax

fid=hnco(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.tau         - the three delays required for the ope-
                            ration of the sequence (see the paper)
                            in seconds. Reasonable values are
                            [2.25e-3, 14e-3, 4e-3]

   parameters.f1_decouple - logical switch controlling proton de-
                            coupling during the T1 period.

   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.

ledwards@cbs.mpg.de
ilya.kuprov@weizmann.ac.il

Examples

An HNCO spectrum of ubiquitin (examples/nmr_proteins/hnco_ubiquitin_theo.m) appears below.

Notes

Spin labels must be set to PDB atom IDs ('CA', 'HA', etc.) in sys.labels for this sequence to work properly.

See also

hncoca.m, protein.m, noesy.m, noesyhsqc.m, hsqc.m

Version 2.3, authors: Luke Edwards, Ilya Kuprov