Dear Crystallographers,
I have run my protein-peptide complex several times on a GE S200
10/300 in buffer A (below). Today, to make a crystallization stock, I
ran the sample in buffer B, and the peak shifted from a consistent
16.0 mL to 13.5mL, which would seem to be ~dimer MW, but I know that
SEC results change as a result of buffer conditions. Could this
drastic a shift be due simply to buffer conditions, or could there
actually be some buffer/ion-dependent dimerization going on? Anyone
have a similar experience?
A: (20mM HEPES, 50mM NaCl, and 5mM CaCl2 pH'd to 8.1 w/ TRIS base)
B: (5mM HEPES, 0mM NaCl, and 1mM CaCl, pH'd to 7.5 w/ TRIS base.)
Jacob Keller
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
cel: 773.608.9185
email: [log in to unmask]
*******************************************
|