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
