Hi,
similarly, 30 sec soak with 0.5 M potassium iodide. But in this case,
the iodides bound specifically to a site where otherwise chloride
binds. These halide binding sites were totally unexpected ...
Best regards,
Dirk.
Am 26.09.2007 um 01:55 schrieb James Whisstock:
Hi - sorry - rather than iodine I meant to say we had had success
with Potassium Iodide (1M for 20 seconds)!
Cheers
James
[EMAIL PROTECTED] wrote:>
Hi,
I do not use their method as such - however, I love heavy atom
soaks and
do them any time I can, so I've got very similar experiences in
the past.
Heavy atoms can bind very quickly even from quite dilute solutions
- the
quickest I've ever soaked (and got useful data) was sodium
chloroplatinate
in under ten minutes at ~ 1mM concentration. The next quickest was
K2Pt(NO2)4 which tends to take between 10 minutes and 30 minutes,
almost
regardless of the concentration. This is by far my favorite HAD
reagent,
incidentally.
In general my soaks are all less than one hour with a few exceptions,
such
as iodine [not iodide!] soak to iodinate tyrosines which is typically
better done during a day or so with very low amount of I2, via vapor
phase.
Artem
Hi,
I'd like to find out how successful the "quick soak" method for
heavy
atom derivatisation proposed by Radaev and Sun:
Sun PD, Radaev S, Kattah M. Generating isomorphous heavy-atom
derivatives by a quick-soak method. Part I: test cases. Acta Cryst.
2002. D58:1092-1098.
has been in comparison to the "classical" method of longer soaks at
low concentrations of heavy atom compound. The method was quite
successful in our hands a few years ago but (fortunately?) it's
becoming increasingly rare that we use heavy atoms. I understand
that
evidence will necessarily be anecdotal, but let's not let that stop
us.
Derek
--
Derek Logan tel: +46 46 222 1443
Associate professor fax: +46 46 222 4692
Molecular Biophysics mob: +46 76 8585 707
Lund University
Box 124, Lund, Sweden
--
Professor James Whisstock
NHMRC Principal Research Fellow / Monash University Senior Logan
fellow
Department of Biochemistry and Molecular Biology
Monash University, Clayton Campus, PO Box 13d, VIC, 3800, Australia
+613 9905 3747 (Phone)
+613 9905 4699 (Fax)
+61 418 170 585 (Mobile)
*******************************************************
Dirk Kostrewa
Gene Center, A 5.07
Ludwig-Maximilians-University
Feodor-Lynen-Str. 25
81377 Munich
Germany
Phone: +49-89-2180-76845
Fax: +49-89-2180-76999
E-mail: [EMAIL PROTECTED]
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