3rn6

<StructureSection load='3rn6' size='340' side='right' caption='[[3rn6]], [[Resolution|resolution]] 2.25&Aring;' scene=''>

<table><tr><td colspan='2'>[[3rn6]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3RN6 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3RN6 FirstGlance]. <br>

</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=IGA:6-AMINO-3,7-DIHYDRO-2H-PURIN-2-ONE'>IGA</scene>, <scene name='pdbligand=PXN:(2S)-1-[3-{[(2R)-2-HYDROXYPROPYL]OXY}-2,2-BIS({[(2R)-2-HYDROXYPROPYL]OXY}METHYL)PROPOXY]PROPAN-2-OL'>PXN</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene><br>

<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3o7u|3o7u]]</td></tr>

<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">codA, b0337, JW0328 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])</td></tr>

<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Cytosine_deaminase Cytosine deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.4.1 3.5.4.1] </span></td></tr>

<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3rn6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3rn6 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3rn6 RCSB], [http://www.ebi.ac.uk/pdbsum/3rn6 PDBsum]</span></td></tr>

<table>

<div style="background-color:#fffaf0;">

== Publication Abstract from PubMed ==

Cytosine deaminase (CDA) from Escherichia coli was shown to catalyze the deamination of isoguanine (2-oxoadenine) to xanthine. Isoguanine is an oxidation product of adenine in DNA that is mutagenic to the cell. The isoguanine deaminase activity in E. coli was partially purified by ammonium sulfate fractionation, gel filtration, and anion exchange chromatography. The active protein was identified by peptide mass fingerprint analysis as cytosine deaminase. The kinetic constants for the deamination of isoguanine at pH 7.7 are as follows: k(cat) = 49 s(-1), K(m) = 72 muM, and k(cat)/K(m) = 6.7 x 10(5) M(-1) s(-1). The kinetic constants for the deamination of cytosine are as follows: k(cat) = 45 s(-1), K(m) = 302 muM, and k(cat)/K(m) = 1.5 x 10(5) M(-1) s(-1). Under these reaction conditions, isoguanine is the better substrate for cytosine deaminase. The three-dimensional structure of CDA was determined with isoguanine in the active site.

 

Rescue of the orphan enzyme isoguanine deaminase.,Hitchcock DS, Fedorov AA, Fedorov EV, Dangott LJ, Almo SC, Raushel FM Biochemistry. 2011 Jun 28;50(25):5555-7. Epub 2011 Jun 7. PMID:21604715<ref>PMID:21604715</ref>

 

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>

*[[Deaminase|Deaminase]]

[[Category: Cytosine deaminase]]

[[Category: Almo, S C.]]

[[Category: Fedorov, A A.]]

[[Category: Fedorov, E V.]]

[[Category: Hitchcock, D S.]]

[[Category: Raushel, F M.]]

[[Category: Amidohydrolase fold]]

[[Category: Isoguanine]]