M. Llosa et al., THE BETA-TUBULIN MONOMER RELEASE FACTOR (P14) HAS HOMOLOGY WITH A REGION OF THE DNAJ PROTEIN, FEBS letters, 397(2-3), 1996, pp. 283-289
p14 is a molecular chaperone involved in beta-tubulin folding which ca
talyzes the release of beta-tubulin monomers from intermediate complex
es, Here we demostrate that active p14 protein which we have purified
from an overproducing Escherichia call strain can also release beta-tu
bulin monomers from tubulin dimers in the presence of an additional co
factor (Z). Analysis of p14 secondary structure suggests that this pro
tein may belong to a family of conserved proteins which share structur
al similarities with the J-domain of DnaJ, We have constructed deletio
ns and site-directed mutations in the p14 gene, A single D to E mutati
on in the region shown in DnaJ to be an essential loop for its functio
n affected the monomer-release activity of p14, These results support
the hypothesis that this p14 loop interacts with beta-tubulin in a sim
ilar fashion as DnaJ interacts with DnaK and suggest a possible role o
f p14 in the folding process.