The title of my PhD thesis was "NMR of inorganic hydrides" but I soon
realized that I was out of my depth with
the theory so switched to something easier to understand (gas phase
electron diffraction). However this involved
taking the (somewhat dangerous) samples by train to Durward
Cruickshank's machine in Glasgow (later
Manchester). Then I managed to find a Weissenberg camera so I was able
to do some crystallography. Two
points that don't seem to have been mentioned yet:
State of the art In-house NMR equipment is an order of magnitude more
expensive than in-house X-ray equipment
(but of course if you need a synchrotron the real costs might be different).
Many NMR structures are more modelled than experimentally determined,
the number of independent experimental
data can be quite small. But the good news is that force fields and
modelling software are improving.
George
On 06/09/2013 08:12 PM, Ethan Merritt wrote:
On Sunday, 09 June 2013, Theresa Hsu wrote:
Dear all
A question for the cross-trained members of this forum - for small sized
proteins, is NMR better than crystallography in terms of data collection
(having crystals in the first place) and data processing? How about membrane
proteins?
A relevant study is the comparison by Yee et al (2005) JACS 127:16512.
<http://pubs.acs.org/doi/abs/10.1021/ja053565+>
They tried to solve 263 small proteins using both NMR and crystallography.
43 only worked for NMR
43 only worked for X-ray
21 could be solved either way
So you could say it was a toss-up, but consider that
- As the size gets larger, NMR becomes increasingly impractical
- 156 (60%) weren't solved by either NMR or crystallography.
What is the relative cost of the failed attempt?
Ethan
--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-33021 or -33068
Fax. +49-551-39-22582
