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hi All,

I run a 1H-15N HMBC experiment on a Bruker AVANCE III 600 MHz spectrometer. But I fail to get the long- range correlation signal. please help me to set the acquisition parameters of the 1H-15 HMBC experiment, especially the “cnst2” (J(XH)) and the “cnst13” (J(XH) long range), or other key parameters.

Thank you very much!

asked Nov 17 '13 at 02:06

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nmrqibebt
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Use "rpar HMBCGP_N15" to load in the standard library parameters for this experiment. Then "getprosol" to load the probe calibrations. As long as the probe calibration file has been properly done, this should work. I ran one about a week ago on our AVIII 500 with a BBFO probe.

cnst13 should normally be set to about 5 Hz, while a N15 HMBC doesn't typically use a low pass filter, so cnst2 isn't used. If you are using a low pass filter, then a value for cnst2 of about 90 Hz would be typical.

Note that the gradient ratios for 15N experiments will be different than for 13C experiments.

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answered Nov 20 '13 at 11:43

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Kirk Marat
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Can I follow this question? What pulse sequence can I use for 2D or 1D 1H-15N HSQC? Thanks.

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answered Dec 05 '13 at 19:08

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A 15N HSQC can typially use the same sequence as a 13C HSQC. The differences will be in the parameters, particularly gradient ratios, delays related to coupling constants, etc. If you are doing proteins in H2O/D2O, then you may need some water suppression (e.g. watergate) and/or flip-back pulses as well.

On Bruker systems, there is a large collections of generic parameter sets which are used in conjunction with the probe calibration ("prosol") files. For example:

rpar HSQCGP_15N
getprosol

should set everything up for you if the probe calibration file has been properly done. If it hasn't, then you will have to adjust all of the pulse lengths and power levels manually.

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answered Dec 06 '13 at 12:50

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Kirk Marat
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I just found that although we have topspin 3.1 installed but the active one we are using are topspin 2.1. My question is is HSQCGP_15N customized pulse sequence on your spectrometer or it is more generic sequence available for any topspin program. If it is not generic could you send me a copy of this pulse sequence so I can compile it? my email is gexiaa at hotmail. Thank you very much. Xia

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answered Dec 06 '13 at 18:27

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HSQCGP_15N is not the pulse sequence, but is a parameter set which includes a pulse sequence as a parameter. I don't know about TopSpin 2.1, but I think it would be included (we are uning 3.1). If HSQCGP_15N is not available use HSQC_GP and adjust gradient ratios and pulse lengths/powers as req. - Kirk Marat (Dec 09 '13 at 07:15)

My erro, the parameter set is called HSQCETGP_15N and the pulse sequence it uses is hsqcetgpsi2. The comments in the pulse sequence will give you the correct gradient ratios. - Kirk Marat (Dec 09 '13 at 07:48)

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Asked: Nov 17 '13 at 02:06

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Last updated: Dec 09 '13 at 07:48

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