View source for 1dr2

==2.3 ANGSTROMS CRYSTAL STRUCTURE OF CHICKEN LIVER DIHYDROFOLATE REDUCTASE COMPLEXED WITH THIONADP+ AND BIOPTERIN==
<StructureSection load='1dr2' size='340' side='right' caption='[[1dr2]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1dr2]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DR2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1DR2 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=TAP:7-THIONICOTINAMIDE-ADENINE-DINUCLEOTIDE+PHOSPHATE'>TAP</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Dihydrofolate_reductase Dihydrofolate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.5.1.3 1.5.1.3] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1dr2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1dr2 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1dr2 RCSB], [http://www.ebi.ac.uk/pdbsum/1dr2 PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/DYR_CHICK DYR_CHICK]] Key enzyme in folate metabolism. Contributes to the de novo mitochondrial thymidylate biosynthesis pathway. Catalyzes an essential reaction for de novo glycine and purine synthesis, and for DNA precursor synthesis. May bind to mRNA. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/dr/1dr2_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
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== Publication Abstract from PubMed ==
The role of the 3'-carboxamide substituent of NADPH in the reduction of pteridine substrates as catalyzed by dihydrofolate reductase (EC 1.5.1.3, DHFR) has been investigated by determining crystal structures at 2.3 A of chicken liver DHFR in a binary complex with oxidized thionicotinamide adenine dinucleotide (thioNADP+) and in a ternary complex with thioNADP+ and biopterin. These structures are isomorphous with those previously reported for chicken liver DHFR [Volz, K.W., Matthews, D.A., Alden, R.A., Freer, S. T., Hansch, C., Kaufman, B. T., &amp; Kraut, J. (1982) J. Biol. Chem. 257, 2528-2536]. ThioNADPH, which has a 3'-carbothioamide substituent in place of a 3'-carboxamide, functions very poorly as a coenzyme for DHFR [Williams, T. J., Lee, T. K., &amp; Dunlap, R. B. (1977) Arch, Biochem. Biophys. 181, 569-579; Stone, S. R., Mark, A., &amp; Morrison, J. F. (1984) Biochemistry 23, 4340-4346]. Comparisons show that, while NADP+ and NADPH bind to DHFR with the pyridine ring and 3'-carboxamide coplanar, the thioamide group is twisted by 23 degrees from the pyridine plane in both the binary and ternary complexes. This twist appears to be due to steric conflict between the thioamide sulfur atom and both the pyridine ring at C4 and the adjacent protein backbone at Ala-9. It results in an unfavorably close contact between the sulfur and the biopterin pteridine ring (0.9 A less than the van der Waals separation) which, on the basis of the refined structure, greatly destabilizes the binding of biopterin.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystal structures of chicken liver dihydrofolate reductase: binary thioNADP+ and ternary thioNADP+.biopterin complexes.,McTigue MA, Davies JF 2nd, Kaufman BT, Kraut J Biochemistry. 1993 Jul 13;32(27):6855-62. PMID:8334118<ref>PMID:8334118</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Dihydrofolate reductase|Dihydrofolate reductase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Dihydrofolate reductase]]
[[Category: Gallus gallus]]
[[Category: /II, J F.Davies]]
[[Category: Kaufman, B T]]
[[Category: Kraut, J]]
[[Category: Mctigue, M A]]
[[Category: Xuong, N H]]
[[Category: Oxidoreductase]]