GLY CaHD CPMG v1 (Kay 2009)

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Basic facts about CaHD_cpmg_GLY_dfh_600_v1

Synopsis: 2D 13C,1H correlation to observe exchange with CPMG at Glycine Cα sites, with selection of CHD and suppression of CH2 moieties

Family: CPMG relaxation dispersion

Sample requirements: U-13C, 50% D isotope labeling

Code authors:  D. Flemming Hansen,  Lewis E. Kay

Copyright: L.E. Kay, University of Toronto

Instructions

Flags and loops

• dm = 'nnny', dmm = 'cccp' ¹³C decoupling during acquisition
• dm2 = 'nnnn', dmm2 = 'cccp'.
• phase = 1,2 for States-TPPI acquisition in t1 ¹³C
• fsat - water presaturation
• fscuba - SCUBA Hα recovery under water presaturation, fsat must be ='y' for scuba to work
• f1180 - start t1 at halfdwell
• ncyc - number of cpmg cycles
• ncyc_dipfinal < 3 - number of times to repeat dipsi-2 program for ¹H-¹³C cross polarisation

Delays

• time_equil - equilibration time
• time_T2 < 40 ms - total time for CPMG trains
• taua - slightly < 1/4J_CH
• taub - 1/4J_CH

1H channel

Carrier at HDO signal ~ 4.77 ppm.

Pulses & power levels:

• pw @ tpwr  : hard pulse - max power
• pw_dip @ t_dip : hetCP dipsi-2 transfer (around 33 us)
• pwsl @ tpwrsl : spinlock during carbon CPMG.

13C channel

Carrier at 43.9 ppm.

Pulses & power levels:

• pw_dip @ dpwr_dip - ¹³C pulse length and power for dipsi hetCP transfer (pw_dip is common for ¹H and ¹³C
• pwc @ dhpwr: hard ¹³C 90^o pulse
• pwc_cp @ dpwr_cp: 90^o pulses flanking the CPMG period
• pwc_ca @ d_ca, phase_ca (phase adjustment), shape = RF_CO_Ca_burp_600_v3: selective (Ca && !CO) pulses
• pwc_reb (<2.750 ms) @ d_reb, shape=shp_reb: A selective Re-burp pulse (Ca(gly) && !Cb(!gly))
• 1/dmf @ dpwr: ¹³C decoupling during acquisition
• 1./dmf_co @ dpwrcodec, dresco, pattern - codecseq: low power adiabadic CO decoupling (e.g. WURST-2) during indirect acquisition

2H channel

Carrier at 4.0 ppm (middle of Gly Hα region)

Pulses & power:

• pwd @ dpwr3_D
• pwd1 @ dpwr3

PFG

Pulses & levels:

• gt0 @ gzlvl0
• gt1 @ gzlvl1
• gt2 @ gzlvl2
• gt3 @ gzlvl3