View source for 4amx


==CRYSTAL STRUCTURE OF THE GRACILARIOPSIS LEMANEIFORMIS ALPHA-1,4- GLUCAN LYASE Covalent Intermediate Complex with 5-fluoro-glucosyl- fluoride==
<StructureSection load='4amx' size='340' side='right'caption='[[4amx]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4amx]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Gracilariopsis_lemaneiformis Gracilariopsis lemaneiformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4AMX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4AMX 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=5GF:5-FLUORO-BETA-D-GLUCOPYRANOSE'>5GF</scene>, <scene name='pdbligand=AFR:2-OXO-1,2,DIDEOXY-5F-D-GLUCOPYRANOSE'>AFR</scene>, <scene name='pdbligand=CSO:S-HYDROXYCYSTEINE'>CSO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=4amx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4amx OCA], [https://pdbe.org/4amx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4amx RCSB], [https://www.ebi.ac.uk/pdbsum/4amx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4amx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9STC1_GRALE Q9STC1_GRALE] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
alpha-1,4-Glucan lyase (EC 4.2.2.13) from the red seaweed Gracilariopsis lemaneiformis cleaves alpha-1,4-glucosidic linkages in glycogen, starch and malto-oligosaccharides, yielding the keto-monosaccharide 1,5-anhydro-D-fructose. The enzyme belongs to glycoside hydrolase family 31 (GH31), but degrades starch via an elimination reaction instead of hydrolysis. The crystal structure shows that the enzyme, like GH31 hydrolases, contains a (beta/alpha)8-barrel catalytic domain with B and B' subdomains, an N-terminal domain N, and the C-terminal domains C and D. The N-terminal domain N of the lyase was found to bind a trisaccharide. Complexes of the enzyme with acarbose and 1-dexoynojirimycin, and two different covalent glycosyl-enzyme intermediates obtained with fluorinated sugar analogues show that, like GH31 hydrolases, the aspartic acid residues D553 and D665 are the catalytic nucleophile and acid, respectively. However, as a unique feature, the catalytic nucleophile is in a position to act also as a base that abstracts a proton from the C2 carbon atom of the covalently bound subsite -1 glucosyl residue, thus explaining the enzyme's unique lyase activity. One Glu to Val mutation in the active site of the homologous alpha-glucosidase from Sulfolobus solfataricus resulted in a shift from hydrolytic to lyase activity, demonstrating that a subtle amino acid difference can promote lyase activity in a GH31 hydrolase.

Crystal structure of alpha-1,4-glucan lyase, a unique glycoside hydrolase family member with a novel catalytic mechanism.,Rozeboom HJ, Yu S, Madrid S, Kalk KH, Zhang R, Dijkstra BW J Biol Chem. 2013 Jul 31. PMID:23902768<ref>PMID:23902768</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4amx" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Gracilariopsis lemaneiformis]]
[[Category: Large Structures]]
[[Category: Dijkstra BW]]
[[Category: Kalk KH]]
[[Category: Madrid S]]
[[Category: Rozeboom HJ]]
[[Category: Yu S]]