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High Field NMR - Experiments

  • The relaxation dispersion experiment is used to determine the exchange time scale in the intermediate-fast exchange regime. It is also used for the slow exchange time scale when a single resonance is observable because of skewed populations.
  • The ZZ-exchange experiment is used for the slow exchange regime when populations under exchange are observable as different resonances.

 

NMR ExperimentsBruker Sequences
N15-RC-CPMG (HSQC)
Relaxation-Compensated CPMG for relaxation dispersion
Loria (1999) JACS 121,2331
hsqcrexetf3gpsitc3d
Acquires pseudo-3D; F3(HN) - F2(N) - F1(vd list)
Uses temperature compensation (tc).
relaxation time = d21 *2 (max. 0.1)
n _cpmg (RF field strength) = vd list (max. 1000 Hz)
t _cpmg = 1/(4*vd) (min. 0.25ms)
#CPMG loop (even number) = COUNTER1 = 2*d21*vd (max. 100)
Set vd list as COUNTER1/(2*d21) and max. 100.
For example, for d21=0.05 (total relaxation time = 100ms), vd lists = 20, 40, 60, ... 1000 (max)
N15-RC-CPMG (TROSY)
Relaxation-Compensated CPMG
for relaxation dispersion
Loria (1999) JBNMR 15,151
trrexetf3gpsitc3dsk
TS (TROSY selected) and TD (TROSY detected) version
Acquires pseudo-3D; F3(HN) - F2(N) - F1(vd list), aqseq 312
Total relaxation time = d21*2 (<= 0.1s)
vd list = cpmg rf field strength, 1000 Hx max
vd list = n/(2*d21) where ni is the even integer
Example; vd = 20, 40, 60, .... 1000 (max) for d21=0.05
Setup is the same as the HSQC version, hsqcrexetf3gpsitc3d
Modified from Bruker trrexetf3gpsitc3d because TROSY was not selected during relaxation.

yl.ts.cpmg_PC, yl.ts.cpmg_PCm
From AG Palmer's Lab.
TS and TD version
Includes correction by Dong (2008) JACS 130, 2432
No use of getprosol
l3 = 0 for no relaxation
l3 = 1 for relaxation dispersion
l2 = 4, 8, 12, ....
l2 = 2, 6, 10,.... with PCm version
cnst1(ms) = relaxT/(4*l2)
l2 and cnst1 determine relaxT and field strength
N15-ZZ-exchange (HSQC)
Farrow (1994) JBNMR 4, 727
hsqczzexf3sk
Acquires pseudo-3D; F3(HN) - F2(N) - F1(vd list)
vdlists are increments of 0.01s.
Modified from Bruker 2D version of hsqctexf3gp 2D
N15-ZZ-exchange (TROSY)
Li (2009) JBNMR 45, 357
ts.zzexsk
Acquires 2D; F2(HN) - F1(N)
TROSY-Selection and TROSY-Detection version
Modified from ts.zzex (from AG Palmer's Lab.) for Bruker compatibility
Uses cnst20(ms) for mixing time
It is different from Sahu (2007) JACS 129, 13232 which uses TROSY-Detection only.
N15-ZZ-exchange (Hybrid)
Li (2013) PNAS 110, 19651
trzzexf3sk
HSQC-TROSY Hybrid version
Acquires pseudo-3D; F3(HN) - F2(N) - F1(vd list)
Uses vdlist as increments of 0.01s.
Modified from trtexf3gp 2D
N15-CEST HSQC
Vallurupalli et al (2012) JACS 124, 8148
hsqc_cest_etf3gpsitc3d
Acquires pseudo-3D; F3(HN) - F2(N) - F1(fq list)
Uses fq3list for 15N saturation frequency as ppm.
     Cautions; use the same number of lines than td1
d21: relaxation time, with the maximum d31 as 0.4s
plw33: 15N saturation rf power
To calibrate 15N saturation rf strength, use hsqcf3rfcalsk
plw19: 1H decoupling power for pcpd8=70us
Use xau su_hsqc_cest_etf3gpsitc3d to set initial plw19 and plw33
Use xau calpowsk to calculate plw33
To calibrate 15N saturation rf strength, use hsqcf3rfcalsk
hsqcf3CESTsk
Acquires pseudo-3D; F3(HN) - F2(N) - F1(fq list)
Uses fq3list for 15N saturation frequency as Hz.
     Cautions; use the same number of lines than td1
d8: relaxation time, maximum is 0.5s (= d9)
cnst25: 15N saturation rf strength which set pldb25
To calibrate 15N saturation rf strength, use hsqcf3rfcalsk
hsqcf3rfcalsk; to calibrate 15N rf power
Acquires 2D: F2(H) - F1(rf strength, Hz)
PLDB35 :15N power for calibration
N15-DEST HSQC
Fawzi et al (2011) Nature 480, 268
hsqc_15Nsat_PLsk
HSQC DEST sequence compatible to Bruker
Modified from hsqc_15Nsat_twoPL.2sk (interleaved version)
pseudo3D: F3(HN) - F2(N) - F1(FQ3LIST), aqseq 312
set up by getprosol and xau su_hsqc_15Nsat_PLsk
plW35: 15N saturation power
     Must be calibrated by calpowsk au program
     about 0.02 W for 100 Hz rf strength on 700B
l9: 15N relaxation time = l9*100ma
FQ3LIST; 15N saturation frequency list as Hz reltative to O3
     The first element is the reference with zero 15N saturation power

hsqcf3rfcalsk is used to calibrate the 15N rf strength by experiment.
     Acquisition: F2(H) - F1(rf strength, Hz) by nutation

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