View source for 3vlw


==Crystal structure of Sphingomonas sp. A1 alginate-binding protein AlgQ1 in complex with mannuronate-guluronate disaccharide==
<StructureSection load='3vlw' size='340' side='right'caption='[[3vlw]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3vlw]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Sphingomonas_sp._A1 Sphingomonas sp. A1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3VLW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3VLW 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&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BEM:BETA-D-MANNURONIC+ACID'>BEM</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=LGU:ALPHA-L-GULURONATE'>LGU</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=3vlw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3vlw OCA], [https://pdbe.org/3vlw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3vlw RCSB], [https://www.ebi.ac.uk/pdbsum/3vlw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3vlw ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9KWT6_SPHSX Q9KWT6_SPHSX] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Alginate is a heteropolysaccharide that consists of beta-D-mannuronate (M) and alpha-L-guluronate (G). The Gram-negative bacterium Sphingomonas sp. A1 directly incorporates alginate into the cytoplasm through the periplasmic solute-binding protein (AlgQ1 and AlgQ2)-dependent ABC transporter (AlgM1-AlgM2/AlgS-AlgS). Two binding proteins with at least four subsites strongly recognize the nonreducing terminal residue of alginate at subsite 1. Here, we show the broad substrate preference of strain A1 solute-binding proteins for M and G present in alginate and demonstrate the structural determinants in binding proteins for heteropolysaccharide recognition through X-ray crystallography of four AlgQ1 structures in complex with saturated and unsaturated alginate oligosaccharides. Alginates with different M/G ratios were assimilated by strain A1 cells and bound to AlgQ1 and AlgQ2. Crystal structures of oligosaccharide-bound forms revealed that in addition to interaction between AlgQ1 and unsaturated oligosaccharides, the binding protein binds through hydrogen bonds to the C4 hydroxyl group of the saturated nonreducing terminal residue at subsite 1. The M residue of saturated oligosaccharides is predominantly accommodated at subsite 1 because of the strict binding of Ser-273 to the carboxyl group of the residue. In unsaturated trisaccharide (DeltaGGG or DeltaMMM)-bound AlgQ1, the protein interacts appropriately with substrate hydroxyl groups at subsites 2 and 3 to accommodate M or G, while substrate carboxyl groups are strictly recognized by the specific residues Tyr-129 at subsite 2 and Lys-22 at subsite 3. Because of this substrate recognition mechanism, strain A1 solute-binding proteins can bind heteropolysaccharide alginate with different M/G ratios.

Recognition of heteropolysaccharide alginate by periplasmic solute-binding proteins of a bacterial ABC transporter.,Nishitani Y, Maruyama Y, Itoh T, Mikami B, Hashimoto W, Murata K Biochemistry. 2012 May 1;51(17):3622-33. doi: 10.1021/bi300194f. Epub 2012 Apr, 23. PMID:22486720<ref>PMID:22486720</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3vlw" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Sphingomonas sp. A1]]
[[Category: Hashimoto W]]
[[Category: Itoh T]]
[[Category: Maruyama Y]]
[[Category: Mikami B]]
[[Category: Murata K]]
[[Category: Nishitani Y]]