a gradient-based sensitivity-enhanced 3D CBCA(CO)NH experiment by typing (the cbcaconhgp3d pulse program

Channel	f1	f2	f3
Nucleus	1H	13C	15N
Offset	o1p	o2p	o3p
Carrier	4.75 ppm	37.36 ppm	115.5 ppm

 

The following hard and shaped pulses applied on the three channels must be previously calibrated:

• Hard 90º and 180º ¹H pulses via the observe f1 channel (p1 and p2 at pl1).
• 90º degree ¹H pulse for broadband DIPSI-2 decoupling via the observe f1 channel (p26=pcpd1 at pl19 using cpdprg1=dipsi2).
• Selective 90 ¹³C pulses applied on the CA/CB or on the CO resonances via the decoupler f2 channel (p13 (about 409u) at sp2, using spnam2=G4.256, spoff2=0).This same pulse is also applied to perform time reversed selective 90 pulses (p13 (about 409u) at sp8, using spnam8=G4tr.256, spoff8=0).
• Selective 180 ¹³C pulses applied on the CA/CB or on the CO resonances via the decoupler f2 channel (p14 (about 256u) at sp3, using spnam3=G3.256, spoff3=0).
• Selective 180 ¹³C pulses applied off-resonance on the CO resonances via the decoupler f2 channel (p14 (about 256u) at sp5, using spnam5=G3.256, spoff5=+130 ppm).
• Selective 180 ¹³C pulses applied off-resonance on the CA resonances via the decoupler f2 channel (p14 (about 256u) at sp7, using spnam7=G3.256, spoff7=-130 ppm).
• Selective 180º ¹³C pulse for selective CA decoupling via the decoupler f2 channel (pcpd2 at pl28=sp15 using cpdprg2=mlevsp180, spnam15=G3.256, and spoff15=+120ppm).
• Hard 90º and 180º ¹⁵N pulses via the decoupler f3 channel (p21 and p22 at pl3).
• 90º ¹⁵N pulse for GARP decoupling during acquisition via the decoupler f3 channel (pcpd3 at pl16 using cpdprg3=garp).

Otherwhise, all required acquisition parameters can be displayed with the ased command. By default:
 

 

Dimension	F3	F2	F1
Nucleus	1H	15N	13C
TD	2048	40	128
Spectral width	NH  (14 ppm)	N  (32ppm)	13CA+13CB  (75 ppm)

 

Interpulse delays:

            d4 is optimized to 1/(4*J_C-H) (1.8 ms)
            d21 and d27 are optimized to 1/(4*J_N-CO) (12.4 ms)
            d22 and d23 are optimized to 1/(4*J_CA-CB) and  1/(4*J_CA-CO) (3.6 ms)
            d26 is optimized to 1/(4*J_N-H) (2.3 ms)

All other delays are automatically calculated from these values. Gradient parameters are already defined and the user must be set the number of scans and dummy scans (by default, ns=4 and ds=16) as a function of sample concentration. The standard gradient parameters are:

Gradient Number	Strength	Duration	Shape
1	gpz1=3	p16=500u	gpnam1=sine.100
2	gpz2=2	p19=1m	gpnam2=sine.100
3	gpz3=2	p29=250u	gpnam1=sine.50
4	gpz4=30	p19=1m	gpnam4=sine.100
5	gpz5=60	p31=2.5m	gpnam5=sine.100
6	gpz6=60.75	p29=250u	gpnam6=sine.50

A frecuency list FQ2LIST must be defined (list has to be stored in the /TOPSPINHOME/exp/stan/nmr/lists/f1 directory) in which the Caliphatic frequency (43 ppm) is set for first part and the CO frequency (173 ppm) is set for second part.

The standard processing parameters are set to:
 

Dimension	F3	F2	F1
SI	2048	256	512
MC2	-	echo/antiecho	States-TPPI
WDW	QSINE	QSINE	QSINE
Offset	2	2	2
ME_mod	no	LPfc	LPfc
NCOEF	0	32	32

 

List of Related Experiments:

Double-Resonance ¹H-¹³C experiments
Double-Resonance ¹H-¹⁵N experiments
Triple-Resonance ¹H-¹³C-¹⁵N backbone experiments
Triple-Resonance ¹H-¹³C-¹⁵N sidechain experiments