A. Fontalba et al., BETA-TUBULIN FOLDING IS MODULATED BY THE ISOTYPE-SPECIFIC CARBOXY-TERMINAL DOMAIN, Journal of Molecular Biology, 246(5), 1995, pp. 628-636
To investigate the contribution of the carboxy-terminal domain in the
process of tubulin folding anal dimer formation, we constructed a beta
(1)-beta(3) tubulin chimaera and two truncated carboxy-terminal beta(3
)-tubulins. The capacity of these altered polypeptides to incorporate
into dimers and into microtubules was tested by non-denaturing electro
phoresis and co-assembly experiments. The chimaera and the truncated p
rotein with a deletion encompassing the last 12 amino acid residues (b
eta(3) Delta C12) were incorporated into dimers and microtubules, thou
gh the level of incorporation was diminished compared to wild-type bet
a(3)-tubulin. However, the level of incorporation of beta(3) Delta C12
into subtilisin-digested dimers tvas similar to the incorporation of
wild-type beta(3)-tubulin. Since subtilisin deletes the carboxy-termin
al region, these results suggest a regulatory role of the carboxyl-ter
minal region in the folding process itself and not in the formation of
the dimer.