What are the minor differences in peptides ? Any PTM's perhaps ? Jürgen
- Jürgen Bosch Johns Hopkins Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Phone: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-3655 http://web.mac.com/bosch_lab/ On Sep 26, 2010, at 3:43 PM, vikrant saa wrote: > > I am working on 45 kd protein (pI 5.3) for crystallization . It is in pGEX > vector.I do the expression (induction 24 degree 16 hrs) and purification from > Rosetta 2 DE3 cells (has additional rare codon).when I run the affinity > chromatography purified protein (cleaved protein after removal of tag) on SDS > PAGE I do find 2 bands (one of 45 kd and other 2-3 kd less). The same pattern > being retained after FPLC. Intensity of both the bands remain same even > after one or two week of storage at 4 degree. Peptide mass fingerprinting > (after trypsin digestion) suggest both are my proteins except minor > difference in some peptide peaks. Is it because of rare codon/degradation > of protein of interest or any other possibilities? Can I use this mixure for > crystallization? > > > With Regards > > Vikrant > > > > > >
