1t3n: Difference between revisions

Revision as of 09:28, 3 May 2008

Structure of the catalytic core of DNA polymerase Iota in complex with DNA and dTTP

OverviewOverview

Almost all DNA polymerases show a strong preference for incorporating the nucleotide that forms the correct Watson-Crick base pair with the template base. In addition, the catalytic efficiencies with which any given polymerase forms the four possible correct base pairs are roughly the same. Human DNA polymerase-iota (hPoliota), a member of the Y family of DNA polymerases, is an exception to these rules. hPoliota incorporates the correct nucleotide opposite a template adenine with a several hundred to several thousand fold greater efficiency than it incorporates the correct nucleotide opposite a template thymine, whereas its efficiency for correct nucleotide incorporation opposite a template guanine or cytosine is intermediate between these two extremes. Here we present the crystal structure of hPoliota bound to a template primer and an incoming nucleotide. The structure reveals a polymerase that is 'specialized' for Hoogsteen base-pairing, whereby the templating base is driven to the syn conformation. Hoogsteen base-pairing offers a basis for the varied efficiencies and fidelities of hPoliota opposite different template bases, and it provides an elegant mechanism for promoting replication through minor-groove purine adducts that interfere with replication.

About this StructureAbout this Structure

1T3N is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

ReferenceReference

Replication by human DNA polymerase-iota occurs by Hoogsteen base-pairing., Nair DT, Johnson RE, Prakash S, Prakash L, Aggarwal AK, Nature. 2004 Jul 15;430(6997):377-80. PMID:15254543 Page seeded by OCA on Sat May 3 09:28:48 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
 [[Image:1t3n.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1t3n |SIZE=350|CAPTION= <scene name='initialview01'>1t3n</scene>, resolution 2.3&Aring;
+The line below this paragraph, containing "STRUCTURE_1t3n", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=DA:2&#39;-DEOXYADENOSINE-5&#39;-MONOPHOSPHATE'>DA</scene>, <scene name='pdbligand=DC:2&#39;-DEOXYCYTIDINE-5&#39;-MONOPHOSPHATE'>DC</scene>, <scene name='pdbligand=DG:2&#39;-DEOXYGUANOSINE-5&#39;-MONOPHOSPHATE'>DG</scene>, <scene name='pdbligand=DOC:2&#39;,3&#39;-DIDEOXYCYTIDINE-5&#39;-MONOPHOSPHATE'>DOC</scene>, <scene name='pdbligand=DT:THYMIDINE-5&#39;-MONOPHOSPHATE'>DT</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=TTP:THYMIDINE-5&#39;-TRIPHOSPHATE'>TTP</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY=
+or leave the SCENE parameter empty for the default display.
-|GENE= POLI ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])
+-->
-|DOMAIN=
+{{STRUCTURE_1t3n|  PDB=1t3n  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1t3n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1t3n OCA], [http://www.ebi.ac.uk/pdbsum/1t3n PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1t3n RCSB]</span>
-}}
 '''Structure of the catalytic core of DNA polymerase Iota in complex with DNA and dTTP'''
@@ Line 30: / Line 27: @@
 [[Category: Prakash, L.]]
 [[Category: Prakash, S.]]
-[[Category: dna]]
+[[Category: Dna]]
-[[Category: dttp]]
+[[Category: Dttp]]
-[[Category: protein]]
+[[Category: Protein]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 09:28:48 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:50:48 2008''