HZQC/HDQC for Bruker (hdqc Zex.rp)
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Basic facts about hdqc_Zex.rp
Synopsis: HZQC and HDQC pulse sequence - allows to measure kon and koff in slow chemial exchange process
Copyright: UCLA, Clubb Lab
HZQC and HDQC pulse sequences allow to measure rates of association and dissociation in molecular complexes, when chemical exchange is slow.
Please see HZQC/HDQC for more details.
Pulse sequence is switched between HZQC and HDQC by changing strengths of gradients gp4 and gp5 as described below.
- ns - number of scans - multiple of 4, because phase cycle has four steps - 
- d1 - recycling delay - [1s]
- d16 - gradient recovery delay - [200μs] (hardware dependent)
- d21 - 1H-15N INEPT delay when 1H is transverse - [2.25ms]
- d22 - 1H-15N INEPT delay when 1H is transverse - [2.72ms]
- L3 - loop counter for mixing time. The length of the Nz period = 10msec*L3 + 3.2msec. - 
- O1p - offset for 1H transmitter - on water resonance - [4.7]
- O2p - offset for 13C transmitter - center of Cα region - 
- O3p - offset for 15N transmitter - center of amide region - 
- p1 - length of hard 1H 90o pulse
- p11 - length of sp1 pulse - [1.2ms]
- sp1 - power level for sp1 pulse
- pl11 - 120dB
- spnam1 - waveforum for sp1 pulse - [Sinc1.1000]
- phcor1 - phase correction for sp1 pulse - 
Selective 90o 1H pulse for water resonance.
- p12 - length of pulse sp2 - [1.2ms]
- sp2 - power level for sp2 pulse
- pl12 - 120dB
- spnam2 - waveform for sp2 - [Sinc1.1000]
Selective 180o 1H for amides, that does not perturb H2O.
- p14 - length of pulse sp4. p14 should invert amide protons, but not excite water - [1.5ms]
- sp4 - power level for sp4 pulse
- pl14 - 120dB
- spnam4 - waveform for sp4 pulse - [Ipurp2.1000]
- spoffs4 - offset of pulse sp4 - center of amide region
- p13 - length of pulse sp3 - [1ms]
- sp3 - power level of sp3 pulse
- pl13 - 120dB
- spnam3 - waveform of pulse sp3 - [gauss]
- phcor5 - phase correction for pulse sp3 - 
- p3 - hard 90o for 13C
- pl2 - power level for 13C 90o
- p12 - hard 90o for 15N
- pl3 - power level for hard 15N 90o pulse
Broadband 15N decoupling is performed during acquisition.
- pcpd3 - length of 90o pulse for waltz16 - 
- pl16 - power level for the 90o pulse within the waltz16 decoupling
- cpdprg3 - program for composite pulse decoupling - [waltz16]
All gradients are of sine bell shape, i.e.spnamN is SINE.100, where N = [1...7]
In addition all gradients are along z axis, so all gpxN and gpyN should be zero.
Values of gradient strength are give in percent, assuming that 100% corresponds to about 50G/cm.
Related parameter is d16 - gradient recovery delay.
- p16 - length of gradient gp1 - [1ms]
- gpz1 - strength of Z gradient gp1 - 
Gradient gp2 is used for the echo-antiecho method of quadrature detection.
- p17 - length of gradient gp2 - [0.5ms]
- gpz2 - strength of gradient gp2 - [-35]
- p20 - length of gradient gp3 - [2ms]
- gpz3 - strength of gradient gp3 - 
gp4 and gp5
- p18 - length of gradient gp4 - [0.5ms]
- p19 - length of gradient gp5 - [1ms]
For HZQC option
- gpz4 - strength of gradient gp4 - [62.9]
- gpz5 - strength of gradieng gp5 - [62.9]
For HDQC option
- gpz4 - strength of gradient gp4 - [77.1]
- gpz5 - strength of gradieng gp5 - [77.1]