1sm1: Difference between revisions
New page: left|200px<br /><applet load="1sm1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sm1, resolution 3.42Å" /> '''COMPLEX OF THE LARGE... |
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[[Image:1sm1.gif|left|200px]]<br /><applet load="1sm1" size=" | [[Image:1sm1.gif|left|200px]]<br /><applet load="1sm1" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1sm1, resolution 3.42Å" /> | caption="1sm1, resolution 3.42Å" /> | ||
'''COMPLEX OF THE LARGE RIBOSOMAL SUBUNIT FROM DEINOCOCCUS RADIODURANS WITH QUINUPRISTIN AND DALFOPRISTIN'''<br /> | '''COMPLEX OF THE LARGE RIBOSOMAL SUBUNIT FROM DEINOCOCCUS RADIODURANS WITH QUINUPRISTIN AND DALFOPRISTIN'''<br /> | ||
==Overview== | ==Overview== | ||
BACKGROUND: The bacterial ribosome is a primary target of several classes | BACKGROUND: The bacterial ribosome is a primary target of several classes of antibiotics. Investigation of the structure of the ribosomal subunits in complex with different antibiotics can reveal the mode of inhibition of ribosomal protein synthesis. Analysis of the interactions between antibiotics and the ribosome permits investigation of the specific effect of modifications leading to antimicrobial resistances.Streptogramins are unique among the ribosome-targeting antibiotics because they consist of two components, streptogramins A and B, which act synergistically. Each compound alone exhibits a weak bacteriostatic activity, whereas the combination can act bactericidal. The streptogramins A display a prolonged activity that even persists after removal of the drug. However, the mode of activity of the streptogramins has not yet been fully elucidated, despite a plethora of biochemical and structural data. RESULTS: The investigation of the crystal structure of the 50S ribosomal subunit from Deinococcus radiodurans in complex with the clinically relevant streptogramins quinupristin and dalfopristin reveals their unique inhibitory mechanism. Quinupristin, a streptogramin B compound, binds in the ribosomal exit tunnel in a similar manner and position as the macrolides, suggesting a similar inhibitory mechanism, namely blockage of the ribosomal tunnel. Dalfopristin, the corresponding streptogramin A compound, binds close to quinupristin directly within the peptidyl transferase centre affecting both A- and P-site occupation by tRNA molecules. CONCLUSIONS: The crystal structure indicates that the synergistic effect derives from direct interaction between both compounds and shared contacts with a single nucleotide, A2062. Upon binding of the streptogramins, the peptidyl transferase centre undergoes a significant conformational transition, which leads to a stable, non-productive orientation of the universally conserved U2585. Mutations of this rRNA base are known to yield dominant lethal phenotypes. It seems, therefore, plausible to conclude that the conformational change within the peptidyl transferase centre is mainly responsible for the bactericidal activity of the streptogramins and the post-antibiotic inhibition of protein synthesis. | ||
==About this Structure== | ==About this Structure== | ||
1SM1 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans] with SYB and DOL as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1SM1 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans] with <scene name='pdbligand=SYB:'>SYB</scene> and <scene name='pdbligand=DOL:'>DOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SM1 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Bartels, H.]] | [[Category: Bartels, H.]] | ||
[[Category: Fucini, P.]] | [[Category: Fucini, P.]] | ||
[[Category: Harms, J | [[Category: Harms, J M.]] | ||
[[Category: Schluenzen, F.]] | [[Category: Schluenzen, F.]] | ||
[[Category: Yonath, A.]] | [[Category: Yonath, A.]] | ||
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[[Category: synercid]] | [[Category: synercid]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:02:54 2008'' | ||
Revision as of 16:03, 21 February 2008
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COMPLEX OF THE LARGE RIBOSOMAL SUBUNIT FROM DEINOCOCCUS RADIODURANS WITH QUINUPRISTIN AND DALFOPRISTIN
OverviewOverview
BACKGROUND: The bacterial ribosome is a primary target of several classes of antibiotics. Investigation of the structure of the ribosomal subunits in complex with different antibiotics can reveal the mode of inhibition of ribosomal protein synthesis. Analysis of the interactions between antibiotics and the ribosome permits investigation of the specific effect of modifications leading to antimicrobial resistances.Streptogramins are unique among the ribosome-targeting antibiotics because they consist of two components, streptogramins A and B, which act synergistically. Each compound alone exhibits a weak bacteriostatic activity, whereas the combination can act bactericidal. The streptogramins A display a prolonged activity that even persists after removal of the drug. However, the mode of activity of the streptogramins has not yet been fully elucidated, despite a plethora of biochemical and structural data. RESULTS: The investigation of the crystal structure of the 50S ribosomal subunit from Deinococcus radiodurans in complex with the clinically relevant streptogramins quinupristin and dalfopristin reveals their unique inhibitory mechanism. Quinupristin, a streptogramin B compound, binds in the ribosomal exit tunnel in a similar manner and position as the macrolides, suggesting a similar inhibitory mechanism, namely blockage of the ribosomal tunnel. Dalfopristin, the corresponding streptogramin A compound, binds close to quinupristin directly within the peptidyl transferase centre affecting both A- and P-site occupation by tRNA molecules. CONCLUSIONS: The crystal structure indicates that the synergistic effect derives from direct interaction between both compounds and shared contacts with a single nucleotide, A2062. Upon binding of the streptogramins, the peptidyl transferase centre undergoes a significant conformational transition, which leads to a stable, non-productive orientation of the universally conserved U2585. Mutations of this rRNA base are known to yield dominant lethal phenotypes. It seems, therefore, plausible to conclude that the conformational change within the peptidyl transferase centre is mainly responsible for the bactericidal activity of the streptogramins and the post-antibiotic inhibition of protein synthesis.
About this StructureAbout this Structure
1SM1 is a Protein complex structure of sequences from Deinococcus radiodurans with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Alterations at the peptidyl transferase centre of the ribosome induced by the synergistic action of the streptogramins dalfopristin and quinupristin., Harms JM, Schlunzen F, Fucini P, Bartels H, Yonath A, BMC Biol. 2004 Apr 1;2:4. PMID:15059283
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