It may be impossible. Two difficulties are conceivable. One is high @solubility, and even at high concentrations, the line width is narrow.

Thanks! Jun Uzawa

Dear Zachery R Belak

to main knowledge the limit of the natural abudance acquisition is the sample concentration since the 15N naturally present is about 0,4% of the total nitrogen, so if for example you have a sample 1mM (the real nitrogen concentration is about 40uM). THerefore if you are able to acheive higher sample concentration eg 2mM with out problem of precipitation and/or aggregation using an high field cryo-probe NMR you can cetrtanilly acquire good HSCQ in a reasonable time (since the 15N concentration is comparable to 80-100uM enriched samples)

if you are interested to produce a human protein in human cells labelled 15N, i have done some trials of 15N labelling in Expi93 using the Bioexpess 6000 medium (Cambridge isotopes) and the preliminary results were promising ans you can find it a the minute 8 of the following video

https://www.blogger.com/video.g?token=AD6v5dwMieb--rE6-qY-WfM4fv8o-2PbxqaWuGxZ7_U3QB5tB113BQ1lEjHxpZhRMLWIWkeHmZV_LcuaESWuqDtZe1L3JI62cDvZaMQyL6BLVQxIRJtuE7IPw8SYCQHKWSV4_CCL0cs

but of course this stategy could be very expensive and appliable only for proteins those show very high productivity in mammalian.

good luck

Manuele