Hi Len,
I have to post this here as a reply to your own address bounced.
Anyway, zinc fingers might be one possibility to look at - zinc ion
coordination is required for their DNA-binding domains to fold correctly. The
relevant binding domains are stable as shortish peptides (20-30 aas long) and
display a rapid cooperative transition from a random coil to a 2-stranded-beta
sheet - alpha-helical structure upon binding to metal ion, which can be
followed by circular dichroism and UV-spectroscopy (the latter if cobalt is
used instead of zinc). Look for papers by Jeremy Berg (a Medline search should
turn him up) and there are also several X-ray and NMR structures of zinc
fingers and steroid hormone receptors (which use similar domains) in the PDB
database where you can extract geometrical information.
All the best,
Andrew
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Andrew Wallace, IRBM P. Angeletti, Pomezia, Italy.
Voice: +39-6-91093434
Fax: +39-6-91093225
Email: wallace at irbm.it
Discussion on phage display, combinatorial libraries, etc. - molreps at irbm.it
DISCLAIMER: I speak only for myself.
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