Ribokinase

In enzymology, a ribokinase (EC 2.7.1.15) is an enzyme that catalyzes the chemical reaction

ATP + d-ribose ⇌ ADP + d-ribose 5-phosphate
ribokinase
Ribokinase dimer, Human
Identifiers
EC number2.7.1.15
CAS number9026-84-0
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

Thus, the two substrates of this enzyme are ATP and d-ribose, whereas its two products are ADP and d-ribose 5-phosphate.

The systematic name of this enzyme class is ATP:d-ribose 5-phosphotransferase. Other names in common use include deoxyribokinase, ribokinase (phosphorylating), and d-ribokinase. This enzyme participates in pentose phosphate pathway.

Ribokinase (RK) belongs to the phosphofructokinase B (PfkB) family of sugar kinases.[1] Other members of this family (also known as the RK family) include adenosine kinase (AK), inosine-guanosine kinase, fructokinase, and 1-phosphofructokinase.[1][2][3] The members of the PfkB/RK family are identified by the presence of three conserved sequence motifs and the enzymatic activity of this family of protein generally shows a dependence on the presence of pentavalent ions.[1][2][4] The conserved NXXE motif, which is a distinctive property of the PfkB family of proteins, is involved in pentavalent ion dependency. The structures of RK and several other PfK family of proteins have been determined from a number of organisms.[5] Despite low sequence similarity between AdK and other PfkB family of proteins, these proteins are quite similar at structural levels.[1]

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1GQT, 1RK2, 1RKA, 1RKD, 1RKS, 1VM7, and 2FV7.

References

  1. Park J, Gupta RS (September 2008). "Adenosine kinase and ribokinase--the RK family of proteins". Cellular and Molecular Life Sciences. 65 (18): 2875–96. doi:10.1007/s00018-008-8123-1. PMID 18560757. S2CID 11439854.
  2. Bork P, Sander C, Valencia A (January 1993). "Convergent evolution of similar enzymatic function on different protein folds: the hexokinase, ribokinase, and galactokinase families of sugar kinases". Protein Science. 2 (1): 31–40. doi:10.1002/pro.5560020104. PMC 2142297. PMID 8382990.
  3. Spychala J, Datta NS, Takabayashi K, Datta M, Fox IH, Gribbin T, Mitchell BS (February 1996). "Cloning of human adenosine kinase cDNA: sequence similarity to microbial ribokinases and fructokinases". Proceedings of the National Academy of Sciences of the United States of America. 93 (3): 1232–7. Bibcode:1996PNAS...93.1232S. doi:10.1073/pnas.93.3.1232. PMC 40062. PMID 8577746.
  4. Maj MC, Singh B, Gupta RS (March 2002). "Pentavalent ions dependency is a conserved property of adenosine kinase from diverse sources: identification of a novel motif implicated in phosphate and magnesium ion binding and substrate inhibition". Biochemistry. 41 (12): 4059–69. doi:10.1021/bi0119161. PMID 11900549.
  5. Sigrell JA, Cameron AD, Jones TA, Mowbray SL (February 1998). "Structure of Escherichia coli ribokinase in complex with ribose and dinucleotide determined to 1.8 A resolution: insights into a new family of kinase structures". Structure. 6 (2): 183–93. doi:10.1016/s0969-2126(98)00020-3. PMID 9519409.

Further reading

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