DELTAFA |
deletion of the flexible arm (FA) hand close to its boundaries with the stalk does not interfere with stability and expression of tRNase ZL. DELTAFA hand variant has a Km ca. 100times higher and a kcat ca. 2times lower than wild-type tRNase Z |
Drosophila melanogaster |
G196A/Pro201A |
increases in Km as compared to wild-type tRNase Z |
Drosophila melanogaster |
G200A |
significant reductions in kcat as compared to wild-type tRNase Z |
Drosophila melanogaster |
G209A |
increases in Km as compared to wild-type tRNase Z |
Drosophila melanogaster |
I212A |
increases in Km as compared to wild-type tRNase Z |
Drosophila melanogaster |
K207A |
increases in Km as compared to wild-type tRNase Z |
Drosophila melanogaster |
K207A |
significant reductions in kcat as compared to wild-type tRNase Z |
Drosophila melanogaster |
K214A/Lys218A |
significant reductions in kcat as compared to wild-type tRNase Z |
Drosophila melanogaster |
L187A |
substitution of alanine causes Km to increase almost as much as deletion of the entire flexible arm hand, with barely any decrease in kcat. A higher concentration of L187A enzyme than that of wild-type tRNase Z has to be used to accommodate the lower catalytic efficiency of the variant |
Drosophila melanogaster |
L206A |
increases in Km as compared to wild-type tRNase Z |
Drosophila melanogaster |
additional information |
a conserved leucine at the ascending stalk/hand boundary causes practically the same increase in Km as the hand deletion, thus nearly eliminating its ability to bind substrate. Km also increases with substitutions in theGP(alpha4-alpha5) loop and at other conserved residues in the flexible arm hand predicted to contact substrate. Substitutions that reduce kcat are clustered in the beta10-beta11 loop |
Drosophila melanogaster |