Activating Compound | Comment | Organism | Structure |
---|---|---|---|
additional information | imidazole buffer is the best buffer, whereas phosphate and HEPES buffers result in enzyme velocities that are only 50-60% of those for imidazole | Arabidopsis thaliana |
Cloned (Comment) | Organism |
---|---|
into the pET28a+ vector at the NdeI and HindIII sites, overexpression of the enzyme with a cleavable N-terminal His6 tag in Escherichia coli BL21 Codon+ cells | Arabidopsis thaliana |
Crystallization (Comment) | Organism |
---|---|
MTAN1 in its apo form and in complex with formycin A and 5'-methylthiotubercidin to a resolution of 2.0 A, 1.9 A and 1.8 A, respectively. By hanging-drop, vapor-diffusion technique. Belongs to space group P21. The monomer of MTAN1 has a mixed alpha/beta structure composed of a twisted, ten-stranded mixed beta sheet flanked by seven alpha helices and two short 3(10) helices. In the MTAN1 crystals, the asymmetric unit contains two monomers, which interact via an interface involving the four loops beta2-beta3, beta4-alpha2, beta6-alpha2b and beta8-alpha4, and the alpha2, alpha2b, and alpha5 helices. Both polar and apolar residues are involved in hydrogen bond and van der Waals interactions | Arabidopsis thaliana |
the intersubunit interface of MTAN is highly hydrophobic and is dominated by van der Waals and hydrophobic interactions | Escherichia coli |
Protein Variants | Comment | Organism |
---|---|---|
F135L | can reduce steric hindrance at the end of the 5'-alkylthio binding subsite, so that longer 5'-substituents may be accommodated more easily in the MTAN2 active site | Arabidopsis thaliana |
F148L | can reduce steric hindrance at the end of the 5'-alkylthio binding subsite | Arabidopsis thaliana |
I132V | no significant structural change | Arabidopsis thaliana |
I145V | no significant structural change | Arabidopsis thaliana |
L168M | has a more extended side chain, may affect the binding of ligands at the 5'-alkylthio position | Arabidopsis thaliana |
L181M | has a more extended side chain, may affect the binding of ligands at the 5'-alkylthio position | Arabidopsis thaliana |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
5'-methylthiotubercidin | combination of a more occluded active site in its open state and reduced ligand-induced conformational changes in the plant in contrast to Escherichia coli MTAN | Arabidopsis thaliana | |
5'-methylthiotubercidin | active site of apo-MTAN is more open, and greater conformational changes upon ligand binding in contrast to Arabidopsis MTAN1 | Escherichia coli | |
Formycin A | - |
Arabidopsis thaliana | |
Formycin A | - |
Escherichia coli | |
additional information | Tris buffer severely inhibits the nucleosidase reactions; Tris buffer severely inhibits the nucleosidase reactions | Arabidopsis thaliana |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0034 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana | |
0.0071 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
27460 | - |
sequence analysis | Arabidopsis thaliana |
28450 | - |
sequence analysis | Arabidopsis thaliana |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q7XA67 | - |
- |
Arabidopsis thaliana | Q9T0I8 | - |
- |
Escherichia coli | - |
- |
- |
Purification (Comment) | Organism |
---|---|
by centrifugation and on Ni-NTA column and by gel filtration | Arabidopsis thaliana |
on Ni-NTA column | Arabidopsis thaliana |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
0.38 | - |
with adenosine as substrate | Arabidopsis thaliana |
0.46 | - |
with 5'-choroadenosine as substrate | Arabidopsis thaliana |
0.83 | - |
with 5'-choroadenosine as substrate | Arabidopsis thaliana |
0.96 | - |
with S-adenosylhomocysteine as substrate | Arabidopsis thaliana |
1.06 | - |
with 5'-iodoadenosine as substrate | Arabidopsis thaliana |
1.36 | - |
with 5'-phenylthioadenosine as substrate | Arabidopsis thaliana |
1.5 | - |
with 5'-butylthioadenosine as substrate | Arabidopsis thaliana |
1.85 | - |
with 5'-isobutylthioadenosine as substrate | Arabidopsis thaliana |
1.98 | - |
with 5'-isobutylthioadenosine as substrate | Arabidopsis thaliana |
2.44 | - |
with 5'-phenylthioadenosine as substrate | Arabidopsis thaliana |
2.6 | - |
with 5'-ethylthioadenosine as substrate | Arabidopsis thaliana |
2.72 | - |
with 5'-butylthioadenosine as substrate | Arabidopsis thaliana |
3.14 | - |
with 5'-iodoadenosine as substrate | Arabidopsis thaliana |
4.42 | - |
with 5'-ethylthioadenosine as substrate | Arabidopsis thaliana |
6.25 | - |
with 5'-methylthioadenosine as substrate | Arabidopsis thaliana |
11.5 | - |
with 5'-methylthioadenosine as substrate | Arabidopsis thaliana |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
5'-butylthioadenosine + phosphate | 24% relative activity | Arabidopsis thaliana | adenine + 5-butylthio-D-ribose 1-phosphate | - |
? | |
5'-butylthioadenosine + phosphate | 25% relative activity | Arabidopsis thaliana | adenine + 5-butylthio-D-ribose 1-phosphate | - |
? | |
5'-chloroadenosine + phosphate | 13% relative activity | Arabidopsis thaliana | adenine + 5-deoxy-5-chloro-D-ribose 1-phosphate | - |
? | |
5'-chloroadenosine + phosphate | 4% relative activity | Arabidopsis thaliana | adenine + 5-deoxy-5-chloro-D-ribose 1-phosphate | - |
? | |
5'-ethylthioadenosine + phosphate | 40% relative activity | Arabidopsis thaliana | adenine + 5-ethylthio-D-ribose 1-phosphate | - |
? | |
5'-ethylthioadenosine + phosphate | 42% relative activity | Arabidopsis thaliana | adenine + 5-ethylthio-D-ribose 1-phosphate | - |
? | |
5'-iodoadenosine + phosphate | 17% relative activity | Arabidopsis thaliana | adenine + 5-deoxy-5-iodo-D-ribose 1-phosphate | - |
? | |
5'-iodoadenosine + phosphate | 28% relative activity | Arabidopsis thaliana | adenine + 5-deoxy-5-iodo-D-ribose 1-phosphate | - |
? | |
5'-isobutylthioadenosine + phosphate | 32% relative activity | Arabidopsis thaliana | adenine + 5-isobutylthio-D-ribose 1-phosphate | - |
? | |
5'-isobutylthioadenosine + phosphate | 17% relative activity | Arabidopsis thaliana | adenine + 5-isobutylthio-D-ribose 1-phosphate | - |
? | |
5'-methylthioadenosine + phosphate | 100% relative activity | Arabidopsis thaliana | adenine + 5-methylthio-D-ribose 1-phosphate | - |
? | |
5'-phenylthioadenosine + phosphate | 39% relative activity | Arabidopsis thaliana | adenine + 5-phenylthio-D-ribose 1-phosphate | - |
? | |
5'-phenylthioadenosine + phosphate | 12% relative activity | Arabidopsis thaliana | adenine + 5-phenylthio-D-ribose 1-phosphate | - |
? | |
adenosine + phosphate | 6% relative activity | Arabidopsis thaliana | adenine + D-ribose 1-phosphate | - |
? | |
additional information | the plant active site is likely less flexible, which may contribute to its reduced efficiency in binding larger substrates. The 5'-alkylthio binding subsite is more constricted in MTAN1 | Arabidopsis thaliana | ? | - |
? | |
S-adenosylhomocysteine + phosphate | 14% relative activity | Arabidopsis thaliana | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
dimer | crystallography | Escherichia coli |
dimer | crystallography | Arabidopsis thaliana |
Synonyms | Comment | Organism |
---|---|---|
5'-methylthioadenosine nucleosidase | - |
Escherichia coli |
5'-methylthioadenosine nucleosidase | - |
Arabidopsis thaliana |
MTAN | - |
Escherichia coli |
MTAN1 | - |
Arabidopsis thaliana |
MTAN2 | - |
Arabidopsis thaliana |
MTN1 | - |
Arabidopsis thaliana |
MTN2 | - |
Arabidopsis thaliana |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
2 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana | |
18.7 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6 | - |
- |
Arabidopsis thaliana |
8 | - |
- |
Arabidopsis thaliana |
Ki Value [mM] | Ki Value maximum [mM] | Inhibitor | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0083 | - |
5'-methylthiotubercidin | at 0.005 mM | Arabidopsis thaliana | |
0.048 | - |
Formycin A | at 0.05 mM | Arabidopsis thaliana |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
588 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana | |
2600 | - |
5'-methylthioadenosine | - |
Arabidopsis thaliana |