Thank you for your reply. I don't actually see anything interacting with
what would be the second SH of the DTT. The atom opposite the Cys sulfur
is at a distance of 3.0 A (could this eventually suggest hydrogen
bonding)?? I have been looking at examples in the PDB, and have found a
few protein structures where the first S of an extended DTT is 3.0 A
away from the S of Cys. Is this feasible for 2 sulfurs to be 3.0 A
apart, and can I apply this to my structure?
Lynn
Markus Rudolph a écrit :
Lynn,
if DTT is connected via its sulfur to Cys (2.03A distance), it is
oxidized and the DTT is extended.
The interesting question then is: why do you see such a constellation
since the cyclic oxidized DTT is more stable than the linear with a nearby
thiol group? could the second SH in DTT be involved in another
interaction?
HTH,
Markus
___________________________________________________________________________________
Markus Rudolph phone: +41 61 68-86420
Dept. Mol. Struct. Biol.
Georg-August University e-mail: [email protected]
Justus-von-Liebig-Weg 11 www.img.bio.uni-goettingen.de/ms-www/index.html
37077 Goettingen, Germany
www.gpmolbio.uni-goettingen.de/faculty/f_rudolph.html
___________________________________________________________________________________
On Mon, 22 Jun 2009, Lynn Gregory-Pauron wrote:
My structure has a Cys that is solvent-exposed and an unidentified 'blob' of
density which is connected to the sulfur of the Cys. The protein was
crystallized in presence of DTT, and DTT does fit the density. However, I do
not know if it is oxidized or not, as the density does not appear to
accommodate the ring conformation of oxidized DTT. Does anyone know of an
article that talks about the chemistry of DTT, reducing agents in
crystallographic structures or have any suggestions as to what is going on?
Thank you,
Lynn
--
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{\*\generator Msftedit 5.41.15.1515;}\viewkind4\uc1\pard\f0\fs24 Lynn
Gregory-Pauron\par
Institut de Pharmacologie et de Biologie Structurale (IPBS)\par
CNRS \endash Universit\'e9 de Toulouse\par
205 route de Narbonne\par
Toulouse, 31077\par
France\par
T\'e9l. + 33 (0) 5 61 17 54 40 \par
[email protected]\par
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