Hi Phil, Must you tag your protein? Have you tried to express it without a tag? Perhaps you can purify the un-tagged protein with a series of chromatographic (or other) steps - particularly if it expresses well.
Eric ================================ Eric T. Larson, PhD Biomolecular Structure Center Department of Biochemistry Box 357742 University of Washington Seattle, WA 98195 email: [email protected] ================================ On Wed, 23 Feb 2011, Philipp Ellinger wrote:
Dear all, I have a question concerning removal of a his-tag sequence. We have crystallized a protein with an important feature at the C-terminal part of the protein. Unfortunately, we cannot express it with a N-terminal his-tag, only with a C-terminal his-tag. Therefore we are looking for a protease which cleaves off the sequence without leaving any extra amino acid on the C-terminus of our protein. Meaning we obtain really the wild type protein. Does anyone know about a protease or cleavage site which is completely removed? Many thanks in advance Phil
