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| | ==Amylomaltase MalQ from Escherichia coli, apo structure== | | ==Amylomaltase MalQ from Escherichia coli, apo structure== |
| - | <StructureSection load='4s3p' size='340' side='right' caption='[[4s3p]], [[Resolution|resolution]] 2.80Å' scene=''> | + | <StructureSection load='4s3p' size='340' side='right'caption='[[4s3p]], [[Resolution|resolution]] 2.80Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4s3p]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Ecoli Ecoli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4S3P OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4S3P FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4s3p]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4S3P OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4S3P FirstGlance]. <br> |
| - | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4s3q|4s3q]], [[4s3r|4s3r]]</td></tr> | + | </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=4s3p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4s3p OCA], [https://pdbe.org/4s3p PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4s3p RCSB], [https://www.ebi.ac.uk/pdbsum/4s3p PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4s3p ProSAT]</span></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">b3416, JW3379, malA, malQ ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI])</td></tr>
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| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/4-alpha-glucanotransferase 4-alpha-glucanotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.25 2.4.1.25] </span></td></tr>
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| - | <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=4s3p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4s3p OCA], [http://pdbe.org/4s3p PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4s3p RCSB], [http://www.ebi.ac.uk/pdbsum/4s3p PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4s3p ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/MALQ_ECOLI MALQ_ECOLI] |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: 4-alpha-glucanotransferase]] | + | [[Category: Escherichia coli K-12]] |
| - | [[Category: Ecoli]] | + | [[Category: Large Structures]] |
| - | [[Category: Schiefner, A]] | + | [[Category: Schiefner A]] |
| - | [[Category: Weiss, S C]] | + | [[Category: Weiss SC]] |
| - | [[Category: Glucoside hydrolase clan h]]
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| - | [[Category: Maltodextrin]]
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| - | [[Category: Maltose]]
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| - | [[Category: Tim barrel]]
| + | |
| - | [[Category: Transferase]]
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| Structural highlights
Function
MALQ_ECOLI
Publication Abstract from PubMed
Amylomaltase MalQ is essential for the metabolism of maltose and maltodextrins in Escherichia coli. It catalyzes transglycosylation/disproportionation reactions in which glycosyl or dextrinyl units are transferred among linear maltodextrins of various lengths. To elucidate the molecular basis of transglycosylation by MalQ, we have determined three crystal structures of this enzyme, i.e. the apo form, its complex with maltose and an inhibitor complex with the transition state analog acarviosine-glucose-acarbose, at resolutions down to 2.1 A. MalQ represents the first example of a mesophilic bacterial amylomaltase and exhibits an N-terminal extension of about 140 residues, in contrast with previously described thermophilic enzymes. This moiety seems unique to amylomaltases from Enterobacteriaceae and folds into two distinct subdomains that associate with different parts of the catalytic core. Intriguingly, the three MalQ crystal structures appear to correspond to distinct states of this enzyme, revealing considerable conformational changes during the catalytic cycle. In particular, the inhibitor complex highlights the requirement of both a 3-OH group and a 4-OH group (or alpha1-4-glycosidic bond) at the acceptor subsite +1 for the catalytically competent orientation of the acid/base catalyst Glu496. Using an HPLC-based MalQ enzyme assay, we could demonstrate that the equilibrium concentration of maltodextrin products depends on the length of the initial substrate: with increasing number of glycosidic bonds less glucose is formed. Thus, both structural and enzymatic data are consistent with the extremely low hydrolysis rates observed for amylomaltases and underline the importance of MalQ for the metabolism of maltodextrins in E. coli.
Structural basis for the interconversion of maltodextrins by MalQ, the amylomaltase of Escherichia coli.,Weiss SC, Skerra A, Schiefner A J Biol Chem. 2015 Jul 2. pii: jbc.M115.667337. PMID:26139606[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Weiss SC, Skerra A, Schiefner A. Structural basis for the interconversion of maltodextrins by MalQ, the amylomaltase of Escherichia coli. J Biol Chem. 2015 Jul 2. pii: jbc.M115.667337. PMID:26139606 doi:http://dx.doi.org/10.1074/jbc.M115.667337
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