Protein Variants | Comment | Organism |
---|---|---|
Y93H | site-directed mutagenesis, the mutant enzyme shows restored activity on uridine in contrast to the wild-type enzyme. The mutant has higher binding affinities to cytidine than the wild-type | Thermus thermophilus |
Y93Q | site-directed mutagenesis, the mutant enzyme shows restored activity on uridine in contrast to the wild-type enzyme. The mutant has higher binding affinities to cytidine than the wild-type | Thermus thermophilus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | reaction kinetics and thermodynamics of wild-type and Y93 mutant enzymes, overview | Thermus thermophilus |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Thermus thermophilus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + cytidine | Thermus thermophilus | - |
ADP + CMP | - |
? | |
ATP + cytidine | Thermus thermophilus DSM 579 | - |
ADP + CMP | - |
? | |
ATP + cytidine | Thermus thermophilus ATCC 27634 | - |
ADP + CMP | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Thermus thermophilus | Q5SKR5 | - |
- |
Thermus thermophilus ATCC 27634 | Q5SKR5 | - |
- |
Thermus thermophilus DSM 579 | Q5SKR5 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + cytidine | - |
Thermus thermophilus | ADP + CMP | - |
? | |
ATP + cytidine | - |
Thermus thermophilus DSM 579 | ADP + CMP | - |
? | |
ATP + cytidine | - |
Thermus thermophilus ATCC 27634 | ADP + CMP | - |
? | |
ATP + uridine | Y93 mutants | Thermus thermophilus | ADP + UMP | - |
? | |
ATP + uridine | Y93 mutants | Thermus thermophilus DSM 579 | ADP + UMP | - |
? | |
ATP + uridine | Y93 mutants | Thermus thermophilus ATCC 27634 | ADP + UMP | - |
? | |
additional information | molecular mechanisms of substrate specificities of uridine-cytidine kinase, overview | Thermus thermophilus | ? | - |
- |
|
additional information | molecular mechanisms of substrate specificities of uridine-cytidine kinase, overview | Thermus thermophilus DSM 579 | ? | - |
- |
|
additional information | molecular mechanisms of substrate specificities of uridine-cytidine kinase, overview | Thermus thermophilus ATCC 27634 | ? | - |
- |
Synonyms | Comment | Organism |
---|---|---|
ttCK | - |
Thermus thermophilus |
UCK | - |
Thermus thermophilus |
uridine-cytidine kinase | - |
Thermus thermophilus |
General Information | Comment | Organism |
---|---|---|
malfunction | UCK from Thermus thermophilus HB8 loses catalytic activity on uridine due to lack of a substrate binding ability and possesses an unusual amino acid, i.e. tyrosine 93 (Tyr93) at the binding site, whereas histidine (His) is located in the other UCKs. Mutagenesis experiments reveal that a replacement of Tyr93 by His or glutamine (Gln) recovers catalytic activity on uridine | Thermus thermophilus |
additional information | molecular dynamics simulations on the wild-type Thermus thermophilus enzyme, two mutant ttCKs, and a human UCK bound to cytidine and three protonation forms of uridine to elucidate their substrate specificity, overview. Three residues, Tyr88, Tyr/His/Gln93 and Arg152 in ttCKs, are important for recognizing the substrates. Arg152 contributes to induce a closed form of the binding site to retain the substrate, and the N3 atom of uridine needs to be deprotonated. Although Tyr88 tightly binds cytidine, it does not sufficiently bind uridine because of lack of the hydrogen bonding. His/Gln93 complements the interaction of Tyr88 and raises the affinity of ttCK to uridine. The crucial distinction between Tyr and His or Gln is a role in the hydrogen-bonding network. Therefore, the ability to form both hydrogen-bonding donor and acceptor is required to bind both uridine and cytidine. Residue interactions and kinetics. Tyr59 and Phe90 form Pi-Pi stackings and CH-Pi interaction with cytidine, and Ile113 interacts with cytidine via a hydrophobic interaction. Tyr88, His93, and Arg152 form hydrogen bonds with the cytidine base moiety, and Asp60 and Arg142 anchor the ribose moiety, role of His/Gln93 in complementing the interaction between Tyr88 and the substrate | Thermus thermophilus |
physiological function | in contrast to other UCK enzymes, UCK of Thermus thermophilus HB8 (ttCK) phosphorylates only cytidine | Thermus thermophilus |