...by lower wavelength, I mean longer wavelength... or lower energy.
Take your pick.
Dave
2008/5/22 David Briggs <[log in to unmask]>:
> Hi Andrew
> You don't say what your protein is crystallised in, or has seen during
> purification, but maybe S- MERCAPTOCYSTEINE might fit?
> (search for CSS in MSD CHEM)
> Do you have lower wavelength data that you might get a sulphur
> anomalous signal to check this?
>
> S-methyl Cysteine might fit as well - but the difference peak and bond
> lengths look more S-S than S-C.
>
> Hope this helps,
>
> Dave
>
> 2008/5/22 Andrew Gulick <[log in to unmask]>:
>> Greetings.
>>
>> I'm wondering if anyone has ever seen something like this. I have a 2.1 A
>> data set (synchrotron data) that is nearing completion. I see density that
>> appears to join a cysteine side chain to a lysine (30 residues away from
>> each other in primary sequence). There is a picture of the density here.
>>
>> http://labs.hwi.buffalo.edu/gulick/cyslys.html
>>
>> I have modeled this in as a Cysteine sulfenic acid (Side chain is Cb-Sg-OH)
>> and refined. There remains a bit of positive Fo-Fc density above the oxygen
>> and the lysine N and sulfenic acid hydroxyl are 1.8A away.
>>
>> I have some other crazy ideas but haven't been able to find any precedent in
>> the literature. Any thoughts on what this might be or if anyone has seen
>> something similar would be greatly appreciated.
>> Andy
>>
>>
>>
>>
>>
>> --
>> Andrew M. Gulick, Ph.D.
>> -----------------------------------
>> (716) 898-8619
>> Hauptman-Woodward Institute
>> 700 Ellicott St
>> Buffalo, NY 14203
>> -----------------------------------
>> Senior Research Scientist
>> Hauptman-Woodward Institute
>> Dept. of Structural Biology, SUNY at Buffalo
>>
>> http://www.hwi.buffalo.edu/Faculty/Gulick/Gulick.html
>> http://labs.hwi.buffalo.edu/gulick
>>
>
>
>
> --
> ============================
> David C. Briggs PhD
> Father & Crystallographer
> http://www.dbriggs.talktalk.net
> AIM ID: dbassophile
> ============================
>
--
============================
David C. Briggs PhD
Father & Crystallographer
http://www.dbriggs.talktalk.net
AIM ID: dbassophile
============================
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