1x3e: Difference between revisions
New page: left|200px<br /><applet load="1x3e" size="450" color="white" frame="true" align="right" spinBox="true" caption="1x3e, resolution 2.15Å" /> '''Crystal structure of... |
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[[Image:1x3e.gif|left|200px]]<br /><applet load="1x3e" size=" | [[Image:1x3e.gif|left|200px]]<br /><applet load="1x3e" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1x3e, resolution 2.15Å" /> | caption="1x3e, resolution 2.15Å" /> | ||
'''Crystal structure of the single-stranded DNA-binding protein from Mycobacterium smegmatis'''<br /> | '''Crystal structure of the single-stranded DNA-binding protein from Mycobacterium smegmatis'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of Mycobacterium smegmatis single-stranded DNA-binding | The structure of Mycobacterium smegmatis single-stranded DNA-binding protein (SSB) has been determined using three data sets collected from related crystals. The structure is similar to that of its homologue from Mycobacterium tuberculosis, indicating that the clamp arrangement that stabilizes the dimer and the ellipsoidal shape of the tetramer are characteristic features of mycobacterial SSBs. The central OB fold is conserved in mycobacterial SSBs as well as those from Escherichia coli, Deinococcus radiodurans and human mitochondria. However, the quaternary structure exhibits considerable variability. The observed plasticity of the subunit is related to this variability. The crystal structures and modelling provide a rationale for the variability. The strand involved in the clamp mechanism, which leads to higher stability of the tetramer, appears to occur in all high-G+C Gram-positive bacteria. The higher stability is perhaps required by these organisms. The mode of DNA binding of mycobacterial SSBs is different from that of E. coli SSB partly on account of the difference in the shape of the tetramers. Another difference between the two modes is that the former contains additional ionic interactions and is more susceptible to salt concentration. | ||
==About this Structure== | ==About this Structure== | ||
1X3E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycobacterium_smegmatis Mycobacterium smegmatis] with CD as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1X3E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mycobacterium_smegmatis Mycobacterium smegmatis] with <scene name='pdbligand=CD:'>CD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1X3E OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Dauter, Z.]] | [[Category: Dauter, Z.]] | ||
[[Category: Jeyakanthan, J.]] | [[Category: Jeyakanthan, J.]] | ||
[[Category: Manjunath, G | [[Category: Manjunath, G P.]] | ||
[[Category: Muniyappa, K.]] | [[Category: Muniyappa, K.]] | ||
[[Category: Saikrishnan, K.]] | [[Category: Saikrishnan, K.]] | ||
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[[Category: oligonucleotide binding fold]] | [[Category: oligonucleotide binding fold]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:50:38 2008'' | ||
Revision as of 16:50, 21 February 2008
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Crystal structure of the single-stranded DNA-binding protein from Mycobacterium smegmatis
OverviewOverview
The structure of Mycobacterium smegmatis single-stranded DNA-binding protein (SSB) has been determined using three data sets collected from related crystals. The structure is similar to that of its homologue from Mycobacterium tuberculosis, indicating that the clamp arrangement that stabilizes the dimer and the ellipsoidal shape of the tetramer are characteristic features of mycobacterial SSBs. The central OB fold is conserved in mycobacterial SSBs as well as those from Escherichia coli, Deinococcus radiodurans and human mitochondria. However, the quaternary structure exhibits considerable variability. The observed plasticity of the subunit is related to this variability. The crystal structures and modelling provide a rationale for the variability. The strand involved in the clamp mechanism, which leads to higher stability of the tetramer, appears to occur in all high-G+C Gram-positive bacteria. The higher stability is perhaps required by these organisms. The mode of DNA binding of mycobacterial SSBs is different from that of E. coli SSB partly on account of the difference in the shape of the tetramers. Another difference between the two modes is that the former contains additional ionic interactions and is more susceptible to salt concentration.
About this StructureAbout this Structure
1X3E is a Single protein structure of sequence from Mycobacterium smegmatis with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structure of Mycobacterium smegmatis single-stranded DNA-binding protein and a comparative study involving homologus SSBs: biological implications of structural plasticity and variability in quaternary association., Saikrishnan K, Manjunath GP, Singh P, Jeyakanthan J, Dauter Z, Sekar K, Muniyappa K, Vijayan M, Acta Crystallogr D Biol Crystallogr. 2005 Aug;61(Pt 8):1140-8. Epub 2005, Jul 20. PMID:16041080
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