1rk2: Difference between revisions
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New page: left|200px<br /><applet load="1rk2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1rk2, resolution 2.25Å" /> '''E. COLI RIBOKINASE C... |
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[[Image:1rk2.jpg|left|200px]]<br /><applet load="1rk2" size=" | [[Image:1rk2.jpg|left|200px]]<br /><applet load="1rk2" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1rk2, resolution 2.25Å" /> | caption="1rk2, resolution 2.25Å" /> | ||
'''E. COLI RIBOKINASE COMPLEXED WITH RIBOSE AND ADP, SOLVED IN SPACE GROUP P212121'''<br /> | '''E. COLI RIBOKINASE COMPLEXED WITH RIBOSE AND ADP, SOLVED IN SPACE GROUP P212121'''<br /> | ||
==Overview== | ==Overview== | ||
The enzyme ribokinase phosphorylates ribose at O5* as the first step in | The enzyme ribokinase phosphorylates ribose at O5* as the first step in its metabolism. The original X-ray structure of Escherichia coli ribokinase represented the ternary complex including ribose and ADP. Structures are presented here for the apo enzyme, as well as the ribose-bound state and four new ternary complex forms. Combined, the structures suggest that large and small conformational changes play critical roles in the function of this kinase. An initially open apo form can allow entry of the ribose substrate. After ribose binding, the active site lid is observed in a closed conformation, with the sugar trapped underneath. This closure and associated changes in the protein appear to assist ribokinase in recognition of the co-substrate ATP as the next step. Binding of the nucleotide brings about further, less dramatic adjustments in the enzyme structure. Additional small movements are almost certainly required during the phosphoryltransfer reaction. Evidence is presented that some types of movements of the lid are allowed in the ternary complex, which may be critical to the creation and breakdown of the transition state. Similar events are likely to take place during catalysis by other related carbohydrate kinases, including adenosine kinase. | ||
==About this Structure== | ==About this Structure== | ||
1RK2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with RIB, ALF, MG and ADP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ribokinase Ribokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.15 2.7.1.15] Full crystallographic information is available from [http:// | 1RK2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=RIB:'>RIB</scene>, <scene name='pdbligand=ALF:'>ALF</scene>, <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=ADP:'>ADP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ribokinase Ribokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.15 2.7.1.15] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RK2 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Ribokinase]] | [[Category: Ribokinase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Cameron, A | [[Category: Cameron, A D.]] | ||
[[Category: Mowbray, S | [[Category: Mowbray, S L.]] | ||
[[Category: Sigrell, J | [[Category: Sigrell, J A.]] | ||
[[Category: ADP]] | [[Category: ADP]] | ||
[[Category: ALF]] | [[Category: ALF]] | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:51:42 2008'' | ||
