Hi Steve, You should definitively follow Jürgen's suggestion and try to solve the structure. If you could get an idea about the crystal packing it would help you to optimize your DNA construct. This is often critical in protein-nucleic acid crystallization. You could try to change the length of your construct (e.g. +/- one nucleotide or base pair), introduce single-base overhangs, vary the position of a binding site (symmetric/asymmetric topology)...
Of course, you could also try some standard optimization procedures like additive screening using a commercial kit or seeding. Good Luck, christian W.M. B. wrote: > Dear All: > > My protein/DNA complex crystal diffracts to 3.2 A ( in-house source). It > crystalized in 20% PEG 8K, NaCaCo 6.5. I tried to add ATP, CaCl2 and > spermidine. The diffaction doesn't improve. Would you please give me > some advice? > > Thanks a lot, > > Steve > > > > _______________________________________________________________________ Dr. Christian Biertümpfel Laboratory of Molecular Biology NIDDK/National Institutes of Health phone: +1 301 402 4647 9000 Rockville Pike, Bldg. 5, Rm. B1-03 fax: +1 301 496 0201 Bethesda, MD 20892-0580 USA _______________________________________________________________________
