This reminds me of the old question:
"Why are proteins so large?"
My long-time suspicion was to "provide a buffer" against the cumulative effect
of mutations and to "suppress unwanted side-reactions" (or whatever 'reaction'
may mean in the context of non-enzymes).
The question has never been adequately answered, as far as I know.
I'll have to read the paper in it's entirety myself, before I comment on it
specifically.
Keep the discussion going...
Christoph
-- *** > NEW PHONE NUMBER: 784-7459 < *** | Christoph Weber Sen. Research Associate | Dept.of Molecular Biology, MB2 619-784-7459 or -8754 (phone) | The Scripps Research Institute 619-554-3757 (FAX) | La Jolla CA 92037-1027 weber@scripps.edu | http://www.scripps.edu/~chazin/people/cw.html