Dear Colleagues,
I implemented the experiment to measure 15N CSA/15N-1H
dipolar cross-correlation rate on our Bruker Avance
system. The experiment was published in JMR 127,
128-133pp (1997) from Dr. Geerten W. Vuister group. I
tested the sequence on a standard 15N labeled protein
with about 80 to 480 scans for reference and
cross-correlated experiments, respectively. The
experiments worked fine. When I tried on our real
system with a large number of scan (1920 scan). The
experiment stopped after a few fids, and the error
message is
“ No points acquired during last scan !! (Digitizer
OK?)”.
This errors happed couple of times, I then asked help
from the Bruker engineers, Borlan Pan and Ron Savage.
They suggested replace the HADC/2 digitizer board and
its power supplier. I did that, and the problem is
still there. There are no such problem with smaller
number of scans (480 or so). I start to suspect
something may not be right in my sequence
implementing. I checked them very carefully, and could
not find anything wrong with it. I am wondering did
anyone implement this experiment (the pulse scheme in
Fig. 1A, JMR, 127, 128-133, 1997) on a Bruker
instrument. If you do, could you kindly send me a copy
so that I can find out whether this problem comes from
my implemented sequence or from hardware.
Thank you very much.
=====
Dr. Weidong Hu
Immunology Division, BRI, City of Hope
1500 Duarte Rd., Duarte, CA 91010
Tel: 626 359-8111, ext: 63416
Fax: 626 301-8186
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Received on Thu Dec 11 2003 - 16:20:12 MST