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1rdb

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[[Image:1rdb.jpg|left|200px]]<br /><applet load="1rdb" size="350" color="white" frame="true" align="right" spinBox="true"
 
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caption="1rdb, resolution 1.9&Aring;" />
 
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'''CRYSTAL STRUCTURES OF RIBONUCLEASE HI ACTIVE SITE MUTANTS FROM ESCHERICHIA COLI'''<br />
 
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==Overview==
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==CRYSTAL STRUCTURES OF RIBONUCLEASE HI ACTIVE SITE MUTANTS FROM ESCHERICHIA COLI==
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In order to investigate the relationships between the three-dimensional structure and the enzymic activity of E. coli RNase HI, three mutant proteins, which were completely inactivated by the replacements of three functional residues, Asp10 by Asn (D10N), Glu48 by Gln (E48Q), and Asp70 by Asn (D70N), were crystallized. Their three-dimensional structures were determined by x-ray crystallography. Although the entire backbone structures of these mutants were not affected by the replacements, very localized conformational changes were observed around the Mg(2+)-binding site. The substitution of an amide group for a negatively charged carboxyl group in common induces the formation of new hydrogen bond networks, presumably due to the cancellation of repulsive forces between carboxyl side chains with negative charges. These conformational changes can account for the loss of the enzymic activity in the mutants, and suggest a possible role for Mg2+ in the hydrolysis. Since the 3 replaced acidic residues are completely conserved in sequences of reverse transcriptases from retroviruses, including human immunodeficiency virus, the concepts of the catalytic mechanism deduced from this structural analysis can also be applied to RNase H activity in reverse transcriptases.
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<StructureSection load='1rdb' size='340' side='right'caption='[[1rdb]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1rdb]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RDB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RDB FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1rdb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rdb OCA], [https://pdbe.org/1rdb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rdb RCSB], [https://www.ebi.ac.uk/pdbsum/1rdb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rdb ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/RNH_ECOLI RNH_ECOLI] Endonuclease that specifically degrades the RNA of RNA-DNA hybrids. RNase H participates in DNA replication; it helps to specify the origin of genomic replication by suppressing initiation at origins other than the oriC locus; along with the 5'-3' exonuclease of pol1, it removes RNA primers from the Okazaki fragments of lagging strand synthesis; and it defines the origin of replication for ColE1-type plasmids by specific cleavage of an RNA preprimer.[HAMAP-Rule:MF_00042]
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/rd/1rdb_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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=1rdb ConSurf].
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<div style="clear:both"></div>
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==About this Structure==
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==See Also==
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1RDB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Ribonuclease_H Ribonuclease H], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.26.4 3.1.26.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RDB OCA].
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*[[Ribonuclease 3D structures|Ribonuclease 3D structures]]
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__TOC__
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==Reference==
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</StructureSection>
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Crystal structures of ribonuclease HI active site mutants from Escherichia coli., Katayanagi K, Ishikawa M, Okumura M, Ariyoshi M, Kanaya S, Kawano Y, Suzuki M, Tanaka I, Morikawa K, J Biol Chem. 1993 Oct 15;268(29):22092-9. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8408067 8408067]
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[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
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[[Category: Ribonuclease H]]
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[[Category: Large Structures]]
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[[Category: Single protein]]
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[[Category: Katayanagi K]]
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[[Category: Katayanagi, K.]]
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[[Category: Morikawa K]]
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[[Category: Morikawa, K.]]
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[[Category: hydrolase(endoribonuclease)]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:49:50 2008''
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Current revision

CRYSTAL STRUCTURES OF RIBONUCLEASE HI ACTIVE SITE MUTANTS FROM ESCHERICHIA COLI

PDB ID 1rdb

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