Dear Benini,Tina, Tim, Patrick, Tom, James, Mark and other CCP4ers,
Thank you very much for your suggestions!
First, as you suggested, I already applied microseeding
(strategies: seeds vs precipitants; seeds vs drop ratio) . SeMet protein
indeed crystallized in that case, but crysta
just out of curiosity, was one Se enough in this case to solve the structure of
your 0.2 kD protein by MAD?
Mark J van Raaij
Laboratorio M-4
Dpto de Estructura de Macromoleculas
Centro Nacional de Biotecnologia - CSIC
c/Darwin 3
E-28049 Madrid, Spain
tel. (+34) 91 585 4616
http://www.cnb.csic.es/
If SeMet oxidation is an issue then EDTA is your friend. This is
because Met, SeMet and even Cys-Cys are not oxidized directly by O2,
but rather via a trace transition metal intermediate. So, keeping
enough chelator around to soak up any trace metals will dramatically
slow down the oxidation
Hi sarah
I believe, you might have used reducing agent in your SeMet-labeled protein
sample.
if avoiding reducing agent is not a problem to your protein (ignoring
Selenium), try to purify/crystallize your protein in the absence of reducing
agent.
if u want to try this use all degassed buffers
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Dear Sarah,
it is very common that SeMet preps behave differently from the native
crystal w.r.t. the crystallisation conditions, and 13Mets for a 43kDa
protein is a lot!
Don't judge a book by its cover: The only way to find out whether your
different
Hi,
I'm now facing a problem about selenomethionine-labelled protein
crystallization..
Native protein crystallized very well and diffracted to 2.5A. However,
SeMet-protein expression level decreased to only 1/10, and its crystals
have different shape with before(native protein crystals have b
