sequence's ends -- crucial to protein folding too?
Frank Küster geb. Fürst
ffrank at rz.uni-potsdam.de
Sat Sep 21 13:04:55 EST 2002
ffrank at rz.uni-potsdam.de (Frank Küster geb. Fürst) wrote,
> "Artem Evdokimov" <AEVDOKIMOZ at cinci.rr.com> schrieb:
> > > You're right. Things are always more complicated if you look closer. One
> > > other example, kind of extreme, comes to my mind: Pro-domain assisted
> > > folding, e.g. in alpha-lytic protease, which is less stable than the
> > > unfolded form after the pro-domain has been cleaved.
> > Let's not forget concanavalin A which is expressed as a chain that undergoes
> > cleavage and re-ligation with a large piece turned around :)
> Is it turned around? I never had close look at the sequence or the
^^ a close look...
> strucutre. But in the legume lectin reviews I read (and I read a couple
> in the last months), they always say that it is circularly
> permuted. That would mean that there is no change in the structure, only
> the old termini are re-ligated and the new ones are free. The original
> termini are very close to each other in the legume lectin monomer
> (separated just by a "non-existing" beta-turn).
I wanted to say: The termini are located relative to each other in a way
that permits to easily connect them by a beta-turn (and this what is
done in ConA, I think). They are oriented correctly, only the connecting
bond is missing.
> I think nobody knows which effect this procedure has on ConA folding,
> because it folds first, and I am not aware of any in vitro study on ConA
before it is processed. At least this is the case for the other
processed legume lectins, pea and lentil lectins and the /vicia/
lectins, which are only cut (elsewhere) and not re-ligated.
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