View source for 1gob


==COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION==
<StructureSection load='1gob' size='340' side='right'caption='[[1gob]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1gob]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GOB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GOB FirstGlance]. <br>
</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[2rn2|2rn2]]</div></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Ribonuclease_H Ribonuclease H], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.26.4 3.1.26.4] </span></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=1gob FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gob OCA], [https://pdbe.org/1gob PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gob RCSB], [https://www.ebi.ac.uk/pdbsum/1gob PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gob ProSAT]</span></td></tr>
</table>
== Function ==
[[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] 
== 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/go/1gob_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/main_output.php?pdb_ID=1gob ConSurf].
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== Publication Abstract from PubMed ==
The insertion of a Gly residue (designated as Gly-80b) between the C-cap of the alpha II-helix (Gln-80) and the N-cap of the alpha III-helix (Trp-81) in Escherichia coli ribonuclease HI enhances the protein stability by 0.4 kcal/mol in delta G (Kimura, S., Nakamura, H., Hashimoto, T., Oobatake, M., &amp; Kanaya, S. (1992) J. Biol. Chem. 267, 21535-21542). Another mutation within the alpha II-helix, Gly-77--&gt;Ala, reduces the stability by 0.9 kcal/mol. Simultaneous introduction of these mutations enhances the stability by 0.8 kcal/mol, indicating that the effects of these mutations are cooperative and not simply independent. We determined the crystal structures of these three mutant proteins (G80b-, A77-, and A77/G80b-RNase H) to investigate this cooperative mechanism of the protein stabilization. The structures revealed that the inserted Gly-80b assumes a left-handed helical conformation in both the G80b- and the A77/G80b-RNase H. This inserted glycine residue allows the formation of a "paperclip", which is a common motif at the C-termini of alpha-helices. Accompanying the formation of the paperclip motif, two intrahelical hydrogen bonds are formed between the backbone atoms (O78-N80b and O80b-N84). The stabilization caused by the insertion of Gly-80b can be ascribed to the formation of these hydrogen bonds. The Gly-77--&gt;Ala substitution destabilizes the protein due to the deformed packing interactions in the hydrophobic core around Ala-77 and the stress in the wedged indole ring of Trp-81. These effects are alleviated by the insertion of Gly-80b, which relaxes the backbone structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Cooperative stabilization of Escherichia coli ribonuclease HI by insertion of Gly-80b and Gly-77--&gt;Ala substitution.,Ishikawa K, Nakamura H, Morikawa K, Kimura S, Kanaya S Biochemistry. 1993 Jul 20;32(28):7136-42. PMID:8393706<ref>PMID:8393706</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1gob" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribonuclease 3D structures|Ribonuclease 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Bacillus coli migula 1895]]
[[Category: Large Structures]]
[[Category: Ribonuclease H]]
[[Category: Ishikawa, K]]
[[Category: Kanaya, S]]
[[Category: Kimura, S]]
[[Category: Morikawa, K]]
[[Category: Nakamura, H]]