Table 4.
Summary of the mutations to the first activity controller residue: effects on PPOs′ copper content and diphenolase/monophenolase activity. The modification of copper content and the activities′ rate are described compared to the wild type of the corresponding enzymes.
|
First activity controller (HisB1+1) | |||||
|---|---|---|---|---|---|
|
Enzyme |
Mutant |
Diphenolase activity |
Monophenolase activity |
Copper % |
Ref. |
|
MdPPO1 |
Ala243Thr |
slower (dopamine: in crystallo activity) |
slower (tyramine: in crystallo activity) |
n.i. |
|
|
ToPPO2 |
Gly240Thr |
−4.0‐fold (4‐methylcatechol: 53.20 s−1) −14‐fold (dopamine: 6.85 s−1) |
−42‐fold (p‐cresol: 0.56 s−1) −18‐fold (tyramine: 0.47 s−1) |
n.i. |
|
|
|
Gly240Asn |
−10‐fold (4‐methylcatechol: 19.66 s−1) −15‐fold (dopamine: 6.77 s−1) |
−14‐fold (p‐cresol: 1.67 s−1) −9.0‐fold (tyramine: 0.92 s−1) |
n.i. |
|
|
ToPPO6 |
Thr250Gly |
∼same (4‐methylcatechol and dopamine) |
n.d. (p‐cresol and tyramine) |
n.i. |
|
|
|
Thr250Asn |
−9.0‐fold (4‐methylcatechol: 6.78 s−1) −9.0‐fold (dopamine: 1.85 s−1) |
n.d. (p‐cresol and tyramine) |
n.i. |
|
|
JrPPO1 |
Asn240Lys |
−37‐fold (dopamine: 2.51 s−1) −103‐fold (l‐DOPA: 1.08 s−1) |
−456‐fold (tyramine: 0.0542 s−1) n.d. (l‐tyrosine) |
40 |
|
|
|
Asn240Gly |
+3.0‐fold (dopamine: 300 s−1) |
−3.0‐fold (tyramine: 7.60 s−1) |
50 |
|
|
JrPPO2 |
Gly240Asn |
−3.0‐fold (dopamine: 66.3 s−1) |
+1.2‐fold (tyramine: 10.9 s−1) |
60 |
|
|
CgAUS |
Thr253Asp |
∼same (dopamine: 530 s−1) |
++ (tyramine: 2.14 s−1) |
45 |
|
|
|
Thr253Asn |
+1.5‐fold (dopamine: 850 s−1) |
++ (tyramine: 1.19 s−1) |
84 |
|
|
|
Thr253Glu |
+2.5‐fold (dopamine: 1394 s−1) |
++ (tyramine: 0.21 s−1) |
47 |
|
|
|
Thr253Gly |
−0.5‐fold (dopamine: 337 s−1) |
++ (tyramine: 0.07 s−1) |
73 |
|
|
|
Thr253Ser |
∼same (dopamine: 500 s−1) |
++ (tyramine: 0.01 s−1) |
53 |
|
|
|
Thr253Cys |
−0.4‐fold (dopamine: 312 s−1) |
++ (tyramine: 0.04 s−1) |
57 |
|
|
|
Thr253Ala |
−4.0‐fold (dopamine: 140 s−1) |
++ (tyramine: 0.05 s−1) |
56 |
|
|
|
Thr253Ile |
−20‐fold (dopamine: 27 s−1) |
n.d. (tyramine) |
58 |
|
|
|
Thr253Lys |
−28‐fold (dopamine: 20 s−1) |
n.d. (tyramine) |
5 |
|
|
SgTYR |
Asn190Gln |
−1900‐fold (l‐DOPA: 1.3 units/mg) |
n.i. |
45 |
|
|
VvTYR |
Gly241Asn |
faster (4‐methylcatechol: SDS‐activity gel) |
faster (p‐tyrosol and tyramine: SDS activity gel) |
n.i. |
|
|
BmTYR |
Asn205Ala |
−8.0‐fold (l‐DOPA) |
−9.0‐fold (l‐tyrosine) |
70 |
|
|
|
Asn205Asp |
−8.0‐fold (l‐DOPA) |
−9.0‐fold (l‐tyrosine) |
60 |
|
n.d.: no detected activity, n.i.: no information from the particular study, ++: generation of monophenolase activity that was not present in the wild type, entries in s‐1 provide the kcat value, while units/mg refers to the specific activity.