View source for 1noz


==T4 DNA POLYMERASE FRAGMENT (RESIDUES 1-388) AT 110K==
<StructureSection load='1noz' size='340' side='right'caption='[[1noz]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1noz]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_virus_T4 Escherichia virus T4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NOZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NOZ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.2&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1noz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1noz OCA], [https://pdbe.org/1noz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1noz RCSB], [https://www.ebi.ac.uk/pdbsum/1noz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1noz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/DPOL_BPT4 DPOL_BPT4] This polymerase possesses two enzymatic activities: DNA synthesis (polymerase) and an exonucleolytic activity that degrades single-stranded DNA in the 3'- to 5'-direction.
== 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/no/1noz_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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/main_output.php?pdb_ID=1noz ConSurf].
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== Publication Abstract from PubMed ==
We report the crystal structure of an NH2-terminal 388-residue fragment of T4 DNA polymerase (protein N388) refined at 2.2 A resolution. This fragment contains both the 3'-5' exonuclease active site and part of the autologous mRNA binding site (J. D. Karam, personal communication). The structure of a complex between the apoprotein N388 and a substrate, p(dT)3, has been refined at 2.5 A resolution to a crystallographic R-factor of 18.7%. Two divalent metal ion cofactors, Zn(II) and Mn(II), have been located in crystals of protein N388 which had been soaked in solutions containing Zn(II), Mn(II), or both. The structure of the 3'-5' exonuclease domain of protein N388 closely resembles the corresponding region in the Klenow fragment despite minimal sequence identity. The side chains of four carboxylate residues that serve as ligands for the two metal ions required for catalysis are located in geometrically equivalent positions in both proteins with a rms deviation of 0.87 A. There are two main differences between the 3'-5' exonuclease active site regions of the two proteins: (I) the OH of Tyr-497 in the Klenow fragment interacts with the scissile phosphate in the active site whereas the OH of the equivalent tyrosine (Tyr-320) in protein N388 points away from the active center; (II) different residues form of the binding pocket for the 3'-terminal bases of the substrate. In the protein N388 complex the 3'-terminal base of p(dT)3 is rotated approximately 60 degrees relative to the position that the corresponding base occupies in the p(dT)3 complex with the Klenow fragment. Finally, a separate domain (residues 1-96) of protein N388 may be involved in mRNA binding that results in translational regulation of T4 DNA polymerase (Pavlov &amp; Karam, 1994).

Crystal structures of an NH2-terminal fragment of T4 DNA polymerase and its complexes with single-stranded DNA and with divalent metal ions.,Wang J, Yu P, Lin TC, Konigsberg WH, Steitz TA Biochemistry. 1996 Jun 25;35(25):8110-9. PMID:8679562<ref>PMID:8679562</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[DNA polymerase 3D structures|DNA polymerase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia virus T4]]
[[Category: Large Structures]]
[[Category: Konigsberg WH]]
[[Category: Lin TC]]
[[Category: Steitz TA]]
[[Category: Wang J]]
[[Category: Yu P]]