Biology:Ribokinase
In enzymology, a ribokinase (EC 2.7.1.15) is an enzyme that catalyzes the chemical reaction
- REDIRECT Template:Chemical reaction
The enzyme originally characterised from calf liver and Lactobacillus plantarum converts the pentose sugar, D-ribose (shown in its open-chain aldehydo form), to ribose 5-phosphate by transferring a phosphate group from the cofactor, adenosine triphosphate (ATP), which is converted to adenosine diphosphate (ADP).[1][2]
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.[3]
Ribokinase (RK) belongs to the phosphofructokinase B (PfkB) family of sugar kinases.[4] Other members of this family (also known as the RK family) include adenosine kinase (AK), inosine-guanosine kinase, fructokinase, and 1-phosphofructokinase.[4][5][6] 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.[4][5][7] 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.[8] Despite low sequence similarity between AdK and other PfkB family of proteins, these proteins are quite similar at structural levels.[4]
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
- ↑ "Purification and properties of calf liver ribokinase". The Journal of Biological Chemistry 219 (1): 221–9. March 1956. doi:10.1016/S0021-9258(18)65786-2. PMID 13295274. http://www.jbc.org/content/219/1/221.full.pdf.
- ↑ "A deoxyribokinase from Lactobacillus plantarum". The Journal of Biological Chemistry 234 (3): 481–7. March 1959. doi:10.1016/S0021-9258(18)70230-5. PMID 13641245. http://www.jbc.org/content/234/3/481.full.pdf.
- ↑ Enzyme 2.7.1.15 at KEGG Pathway Database.
- ↑ 4.0 4.1 4.2 4.3 "Adenosine kinase and ribokinase--the RK family of proteins". Cellular and Molecular Life Sciences 65 (18): 2875–96. September 2008. doi:10.1007/s00018-008-8123-1. PMID 18560757.
- ↑ 5.0 5.1 "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. January 1993. doi:10.1002/pro.5560020104. PMID 8382990.
- ↑ "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. February 1996. doi:10.1073/pnas.93.3.1232. PMID 8577746. Bibcode: 1996PNAS...93.1232S.
- ↑ "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. March 2002. doi:10.1021/bi0119161. PMID 11900549.
- ↑ "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. February 1998. doi:10.1016/s0969-2126(98)00020-3. PMID 9519409.
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