View source for 1ahc


==THE N-GLYCOSIDASE MECHANISM OF RIBOSOME-INACTIVATING PROTEINS IMPLIED BY CRYSTAL STRUCTURES OF ALPHA-MOMORCHARIN==
<StructureSection load='1ahc' size='340' side='right' caption='[[1ahc]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ahc]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AHC OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1AHC FirstGlance]. <br>
</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/rRNA_N-glycosylase rRNA N-glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.22 3.2.2.22] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ahc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ahc OCA], [http://pdbe.org/1ahc PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1ahc RCSB], [http://www.ebi.ac.uk/pdbsum/1ahc PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1ahc ProSAT]</span></td></tr>
</table>
== 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/ah/1ahc_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=1ahc ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: alpha-Momorcharin (alpha MMC) is a type I ribosome-inactivating protein. It inhibits protein synthesis by hydrolytically removing a specific adenine residue from a highly conserved, single-stranded loop of rRNA. RESULTS: Here we describe the determination and refinement of the crystal structures of alpha MMC in the native state and in complexes with the product, adenine, and a substrate analogue, formycin 5'-monophosphate (FMP) at high resolution. Both adenine and the base of FMP are tightly bound; the ribose of bound FMP adopts a strained, high-energy conformation, which may mimic the structure of the transition state. CONCLUSIONS: These structures indicate that residues Tyr70, Glu160 and Arg163 of alpha MMC are the most critical for catalysis. We propose that the strained conformation of the ribose in the target adenosine weakens the glycoside bond. Partial protonation mediated by Arg163 then facilitates N-glycoside bond cleavage, leading to the formation of an oxycarbonium ion intermediate which is stabilized by the negatively-charged Glu160. Tyr70 adopts subtly different conformations in the three structures implying that it may be important in substrate recognition and perhaps catalysis.

The N-glycosidase mechanism of ribosome-inactivating proteins implied by crystal structures of alpha-momorcharin.,Ren J, Wang Y, Dong Y, Stuart DI Structure. 1994 Jan 15;2(1):7-16. PMID:8075985<ref>PMID:8075985</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 1ahc" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribosome inactivating protein|Ribosome inactivating protein]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: RRNA N-glycosylase]]
[[Category: Dong, Y]]
[[Category: Ren, J]]
[[Category: Stuart, D I]]
[[Category: Wang, Y]]
[[Category: Glycosidase]]