Could you have a threonine with a formylated side chain?
Check out following ref as an example:
HS. Duewel and JF. Honek
Journal of Protein Chemistry Issue Volume 17, Number 4 / May, 1998
Best wishes
James
-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of
Jie Liu
Sent: Friday, September 28, 2007 1:43 PM
To: [log in to unmask]
Subject: [ccp4bb] Modified N-terminal throenine?
Dear all
I am refining a peptide structure with an N-terminal throenine.
However, the density map of the N-terminal part looks strange, the first
throenine does not fit in well while the second valine fits very well.
It seems that this throenine was modified somehow during protein
production. The peptide was expressed in E.Coli and cleavaged by Formic
Acid and Cyanogen Bromide, then purified by HPLC and lyophilized.
Does anyone have similar experience of a modified N-terminal throenine?
If so, please kindly point to me a reference.
Thank you.
Jie Liu
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