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2cvv
From Proteopedia
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[[Image:2cvv.gif|left|200px]] | [[Image:2cvv.gif|left|200px]] | ||
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'''Structures of Yeast Ribonucleotide Reductase I''' | '''Structures of Yeast Ribonucleotide Reductase I''' | ||
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[[Category: Uchiki, T.]] | [[Category: Uchiki, T.]] | ||
[[Category: Xu, H.]] | [[Category: Xu, H.]] | ||
| - | [[Category: | + | [[Category: Dntp regulation]] |
| - | [[Category: | + | [[Category: Eukaryotic]] |
| - | [[Category: | + | [[Category: Ribonucleotide reductase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 23:10:26 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 20:10, 3 May 2008
Structures of Yeast Ribonucleotide Reductase I
Overview
Ribonucleotide reductase catalyzes a crucial step in de novo DNA synthesis and is allosterically controlled by relative levels of dNTPs to maintain a balanced pool of deoxynucleoside triphosphates in the cell. In eukaryotes, the enzyme comprises a heterooligomer of alpha(2) and beta(2) subunits. The alpha subunit, Rnr1, contains catalytic and regulatory sites. Here, we report the only x-ray structures of the eukaryotic alpha subunit of ribonucleotide reductase from Saccharomyces cerevisiae. The structures of the apo-, AMPPNP only-, AMPPNP-CDP-, AMPPNP-UDP-, dGTP-ADP- and TTP-GDP-bound complexes give insight into substrate and effector binding and specificity cross-talk. These are Class I structures with the only fully ordered catalytic sites, including loop 2, a stretch of polypeptide that spans specificity and catalytic sites, conferring specificity. Binding of specificity effector rearranges loop 2; in our structures, this rearrangement moves P294, a residue unique to eukaryotes, out of the catalytic site, accommodating substrate binding. Substrate binding further rearranges loop 2. Cross-talk, by which effector binding regulates substrate preference, occurs largely through R293 and Q288 of loop 2, which are analogous to residues in Thermotoga maritima that mediate cross-talk. However loop-2 conformations and residue-substrate interactions differ substantially between yeast and T. maritima. In most effector-substrate complexes, water molecules help mediate substrate-loop 2 interactions. Finally, the substrate ribose binds with its 3' hydroxyl closer than its 2' hydroxyl to C218 of the catalytic redox pair. We also see a conserved water molecule at the catalytic site in all our structures, near the ribose 2' hydroxyl.
About this Structure
2CVV is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Structures of eukaryotic ribonucleotide reductase I provide insights into dNTP regulation., Xu H, Faber C, Uchiki T, Fairman JW, Racca J, Dealwis C, Proc Natl Acad Sci U S A. 2006 Mar 14;103(11):4022-7. Epub 2006 Mar 6. PMID:16537479 Page seeded by OCA on Sat May 3 23:10:26 2008
