Don't forget to check the anomalous difference Fourier - this may fix any S
atoms - the resolution is god enough
Eleanor
On 18 January 2015 at 01:12, Robert Stroud wrote:
> I suspect it may be a reaction with your reducing agent. What did you use
> either in the preparation, or in the crystalliz
I suspect it may be a reaction with your reducing agent. What did you use
either in the preparation, or in the crystallization. If you didn’t have
reducing agent it probably oxidized to sulfuric acid. You should figure it out
with difference maps and maybe mass spec also.
bob
> On Jan 17, 2015,
Maybe somehow do partial cys partial cme, refine occupancies—is this possible
in refmac?
JPK
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of sreetama
das
Sent: Saturday, January 17, 2015 3:11 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] additional density on
Onderwerp: [ccp4bb] additional density on cysteine residue
Dear Users,
I am solving a structure from x-ray diffraction data (1.62A resolution).
The protein has a single cysteine residue (which is also the catalytic
residue), and it has a positive density on it (fig 1; R/Rfree = 16.88/19.94).
Dear Sreetama,
I would consider the possibility that this active site cysteine is involved in
a mixed-disulfide with beta-mercaptoethanol, which is present at a considerable
concentration in your protein buffer.
The fact that the residual density in both the Fo-Fc and 2Fo-Fc maps actually
incr
