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Hi Pat,
Its surprising that I have noticed similar effects on the crystal
growth of my new protein in the last few weeks. They are thick,
hexagonal, long and hollow! They grow out of PEG. The edges are
fragile! Hope we are not working on the same protein!!
By changing the PEG from high to low molecular weights and a
variation in the pH, had a dramatic affect. Now they are much thicker
and round shaped edges. Did not check the diffraction yet!!
Good luck!
Anthony
________________________________
Anthony Addlagatta, PhD
HHMI Research Associate
Institute of Molecular Biology
University of Oregon
Eugene, OR-97403
Phone: (541) 346-5867
Fax: (541)346-5270
Web: http://darkwing.uoregon.edu/~anthony
On Dec 5, 2006, at 10:31 AM, Patrick Loll wrote:
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We have a system where we can produce rod-shaped crystals that show
a classic depletion imperfection--the rods are essentially hollow
for most of their length, suggesting that growth is proceeding in
this direction more rapidly than fresh protein can diffuse into the
area (picture a long hexagonal rod with a perfect conical hole
bored into one end, extending for most of the rod's length).
Simple-minded optimization experiments (e.g., [PEG] vs. [salt] vs.
pH) have clear-cut effects on nucleation, but don't seem to alter
crystal shape, which I interpret as meaning that growth occurs
rapidly once nucleation has taken place.
What are peoples' thoughts on improving the morphology? We're
currently exploring whether additives can selectively poison growth
along the long axis, but I'd be curious to hear other ideas. For
example, might gels help, or are they mainly effective in
controlling nucleation?
They ARE pretty cool looking. I wonder if there's a market for
nanovases...
Pat
----------------------------------------------------------------------
-----------------
Patrick J. Loll, Ph. D. (215) 762-7706
Associate Professor FAX: (215) 762-4452
Department of Biochemistry & Molecular Biology
Director, Biochemistry Graduate Program
Drexel University College of Medicine
Room 10-102 New College Building
245 N. 15th St., Mailstop 497
Philadelphia, PA 19102-1192 USA
[EMAIL PROTECTED]
