1law: Difference between revisions

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New page: left|200px<br /><applet load="1law" size="450" color="white" frame="true" align="right" spinBox="true" caption="1law, resolution 1.8Å" /> '''STABILIZATION OF ESCH...
 
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'''STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY CAVITY-FILLING MUTATIONS WITHIN A HYDROPHOBIC CORE'''<br />


==Overview==
==STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY CAVITY-FILLING MUTATIONS WITHIN A HYDROPHOBIC CORE==
The crystal structure of Escherichia coli ribonuclease HI has a cavity, near Val-74 within the protein core. In order to fill the cavity space, we, constructed two mutant proteins, V74L and V74I, in which Val-74 was, replaced with either Leu or Ile, respectively. The mutant proteins are, stabilized, as revealed by a 2.1-3.7 degrees C increase in the Tm values, as compared to the wild-type protein at pH values of 3.0 and 5.5. The, mutant protein V74A, in which Val-74 is replaced with Ala, was also, constructed to analyze the reverse effect. The stability of V74A decreases, by 7.6 degrees C at pH 3.0 and 12.7 degrees C at pH 5.5 in Tm as compared, to those values for the wild-type protein. None of the three mutations, significantly affect the enzymatic activity. The crystal structures of, V74L and V74I, determined at 1.8-A resolution, are almost identical to, that of the wild-type protein, except for the mutation site. In the two, mutant proteins, calculation by the Voronoi procedure shows that the, cavity volumes around the individual mutation sites are remarkably reduced, as compared to that in the wild-type protein. These results indicate that, the introduction of a methylene group into the cavity, without causing, steric clash, contributes to an increase in the hydrophobic interaction, within the protein core and thereby enhances protein stability. We also, discuss the role of the Leu side chain, which can assume many different, local conformations on a helix without sacrificing thermostability.
<StructureSection load='1law' size='340' side='right'caption='[[1law]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1law]] 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=1LAW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LAW 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]] 1.8&#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=1law FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1law OCA], [https://pdbe.org/1law PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1law RCSB], [https://www.ebi.ac.uk/pdbsum/1law PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1law 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/la/1law_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=1law ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1LAW 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://ispc.weizmann.ac.il/oca-bin/ocashort?id=1LAW OCA].
*[[Ribonuclease 3D structures|Ribonuclease 3D structures]]
 
__TOC__
==Reference==
</StructureSection>
Stabilization of Escherichia coli ribonuclease HI by cavity-filling mutations within a hydrophobic core., Ishikawa K, Nakamura H, Morikawa K, Kanaya S, Biochemistry. 1993 Jun 22;32(24):6171-8. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8390295 8390295]
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Ribonuclease H]]
[[Category: Large Structures]]
[[Category: Single protein]]
[[Category: Ishikawa K]]
[[Category: Ishikawa, K.]]
[[Category: Kanaya S]]
[[Category: Kanaya, S.]]
[[Category: Morikawa K]]
[[Category: Morikawa, K.]]
[[Category: Nakamura H]]
[[Category: Nakamura, H.]]
[[Category: hydrolase]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 20:26:12 2007''

Latest revision as of 10:31, 14 February 2024

STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY CAVITY-FILLING MUTATIONS WITHIN A HYDROPHOBIC CORESTABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY CAVITY-FILLING MUTATIONS WITHIN A HYDROPHOBIC CORE

Structural highlights

1law is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.8Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

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

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1law, resolution 1.80Å

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