B. Adams et al., THE ROLE OF THE C-TERMINAL LYSINE IN THE HINGE BENDING MECHANISM OF YEAST PHOSPHOGLYCERATE KINASE, FEBS letters, 385(1-2), 1996, pp. 101-104
Treatment of yeast phosphoglycerate kinase (PGK) with trypsin results
in a fourfold increase in the V-max of this enzyme, without affecting
the K-m. This activation is shown to be due to the removal of the C-te
rminal lysine residue. The C-terminal sequence folds back over the N-t
erminal domain and contacts the extreme N-terminal sequence which fold
s onto the C-terminal domain, thus making many of the inter-domain con
tacts in this two domain protein. Previous studies have shown that thi
s C-terminal region is important in mediating the conformational chang
es required during catalysis by yeast PGK. Observation of the three-di
mensional structure of this enzyme suggests that removal of the C-term
inal lysine residue will strengthen the interaction between K5 and E41
3. This indicates that this salt bridge stabilises the enzyme in the h
igher activity form, while the presence of K415 reduces the strength o
f that interaction.