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==CRYSTAL STRUCTURE OF A HIGHLY SPECIFIC ASPERGILLUS RIBOTOXIN, RESTRICTOCIN== | |||
<StructureSection load='1aqz' size='340' side='right'caption='[[1aqz]], [[Resolution|resolution]] 1.70Å' scene=''> | |||
== Structural highlights == | |||
| | <table><tr><td colspan='2'>[[1aqz]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Aspergillus_restrictus Aspergillus restrictus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AQZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AQZ 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]] 1.7Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene></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=1aqz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1aqz OCA], [https://pdbe.org/1aqz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1aqz RCSB], [https://www.ebi.ac.uk/pdbsum/1aqz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1aqz ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/RNMG_ASPRE RNMG_ASPRE] This purine-specific ribonuclease cleaves 28S RNA in eukaryotic ribosomes, inhibits protein synthesis, and shows antitumor activity. | |||
== 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/aq/1aqz_consurf.spt"</scriptWhenChecked> | ||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1aqz ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
BACKGROUND: Restriction, a highly specific ribotoxin made by the fungus Aspergillus restrictus, cleaves a single phosphodiester bond in the 28S RNA of eukaryotic ribosomes, inhibiting protein synthesis. The sequence around this cleavage site is a binding site for elongation factors, and is conserved in all cytoplasmic ribosomes. The catalytic mechanism of restrictocin and the reasons for its high substrate specificity are unknown. No structure has been determined for any other member of the Aspergillus ribotoxin family. RESULTS: The crystal structure of restrictocin was determined at 2.1 A resolution by single isomorphous replacement and anomalous scattering techniques, and refined to 1.7 A resolution using synchrotron Laue data. The structural core of the protein, in which a three-turn alpha helix is packed against a five-stranded antiparallel beta sheet, can be well aligned with that of ribonuclease T1. Large positively charged peripheral loops near the active site construct a platform with a concave surface for RNA binding. CONCLUSIONS: Restriction appears to combine the catalytic components of T1 ribonucleases with the base recognition components of Sa ribonucleases. Modeling studies using an NMR structure of an RNA substrate analog suggest that the tertiary structure of the substrate RNA is important in protein-RNA recognition, fitting closely into the concavity of the presumed binding site. We speculate that the large 39-residue loop L3, which has similarities to loops found in lectin sugar-binding domains, may be responsible for restrictocin's ability to cross cell membranes. | BACKGROUND: Restriction, a highly specific ribotoxin made by the fungus Aspergillus restrictus, cleaves a single phosphodiester bond in the 28S RNA of eukaryotic ribosomes, inhibiting protein synthesis. The sequence around this cleavage site is a binding site for elongation factors, and is conserved in all cytoplasmic ribosomes. The catalytic mechanism of restrictocin and the reasons for its high substrate specificity are unknown. No structure has been determined for any other member of the Aspergillus ribotoxin family. RESULTS: The crystal structure of restrictocin was determined at 2.1 A resolution by single isomorphous replacement and anomalous scattering techniques, and refined to 1.7 A resolution using synchrotron Laue data. The structural core of the protein, in which a three-turn alpha helix is packed against a five-stranded antiparallel beta sheet, can be well aligned with that of ribonuclease T1. Large positively charged peripheral loops near the active site construct a platform with a concave surface for RNA binding. CONCLUSIONS: Restriction appears to combine the catalytic components of T1 ribonucleases with the base recognition components of Sa ribonucleases. Modeling studies using an NMR structure of an RNA substrate analog suggest that the tertiary structure of the substrate RNA is important in protein-RNA recognition, fitting closely into the concavity of the presumed binding site. We speculate that the large 39-residue loop L3, which has similarities to loops found in lectin sugar-binding domains, may be responsible for restrictocin's ability to cross cell membranes. | ||
Insights into specificity of cleavage and mechanism of cell entry from the crystal structure of the highly specific Aspergillus ribotoxin, restrictocin.,Yang X, Moffat K Structure. 1996 Jul 15;4(7):837-52. PMID:8805570<ref>PMID:8805570</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1aqz" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Aspergillus restrictus]] | [[Category: Aspergillus restrictus]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Moffat | [[Category: Moffat K]] | ||
[[Category: Yang | [[Category: Yang X]] | ||
Latest revision as of 09:23, 30 October 2024
CRYSTAL STRUCTURE OF A HIGHLY SPECIFIC ASPERGILLUS RIBOTOXIN, RESTRICTOCINCRYSTAL STRUCTURE OF A HIGHLY SPECIFIC ASPERGILLUS RIBOTOXIN, RESTRICTOCIN
Structural highlights
FunctionRNMG_ASPRE This purine-specific ribonuclease cleaves 28S RNA in eukaryotic ribosomes, inhibits protein synthesis, and shows antitumor activity. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND: Restriction, a highly specific ribotoxin made by the fungus Aspergillus restrictus, cleaves a single phosphodiester bond in the 28S RNA of eukaryotic ribosomes, inhibiting protein synthesis. The sequence around this cleavage site is a binding site for elongation factors, and is conserved in all cytoplasmic ribosomes. The catalytic mechanism of restrictocin and the reasons for its high substrate specificity are unknown. No structure has been determined for any other member of the Aspergillus ribotoxin family. RESULTS: The crystal structure of restrictocin was determined at 2.1 A resolution by single isomorphous replacement and anomalous scattering techniques, and refined to 1.7 A resolution using synchrotron Laue data. The structural core of the protein, in which a three-turn alpha helix is packed against a five-stranded antiparallel beta sheet, can be well aligned with that of ribonuclease T1. Large positively charged peripheral loops near the active site construct a platform with a concave surface for RNA binding. CONCLUSIONS: Restriction appears to combine the catalytic components of T1 ribonucleases with the base recognition components of Sa ribonucleases. Modeling studies using an NMR structure of an RNA substrate analog suggest that the tertiary structure of the substrate RNA is important in protein-RNA recognition, fitting closely into the concavity of the presumed binding site. We speculate that the large 39-residue loop L3, which has similarities to loops found in lectin sugar-binding domains, may be responsible for restrictocin's ability to cross cell membranes. Insights into specificity of cleavage and mechanism of cell entry from the crystal structure of the highly specific Aspergillus ribotoxin, restrictocin.,Yang X, Moffat K Structure. 1996 Jul 15;4(7):837-52. PMID:8805570[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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