4e8d: Difference between revisions
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The | ==Crystal structure of streptococcal beta-galactosidase== | ||
<StructureSection load='4e8d' size='340' side='right'caption='[[4e8d]], [[Resolution|resolution]] 1.80Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4e8d]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptococcus_pneumoniae_TIGR4 Streptococcus pneumoniae TIGR4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4E8D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4E8D 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]] 1.8Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=4e8d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4e8d OCA], [https://pdbe.org/4e8d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4e8d RCSB], [https://www.ebi.ac.uk/pdbsum/4e8d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4e8d ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/A0A0H2UN19_STRPN A0A0H2UN19_STRPN] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The surface-exposed beta-galactosidase BgaC from Streptococcus pneumoniae was reported to be a virulence factor because of its specific hydrolysis activity towards the beta(1,3)-linked galactose and N-acetylglucosamine [Galbeta(1,3)NAG] moiety of oligosaccharides on the host molecules. Here we report the crystal structure of BgaC at 1.8 and its complex with galactose at 1.95 . At pH 5.5 to 8.0, BgaC exists as a stable homodimer, each subunit of which consists of three distinct domains: a catalytic domain of a classic (beta/alpha)8 TIM barrel, followed by two all-beta domains (ABDs) of unknown function. The side-walls of the TIM beta-barrel and a loop extended from the first ABD constitute the active site. Superposition of the galactose-complexed structure to the apo-form revealed significant conformational changes of residues Trp243 and Tyr455. Simulation of a putative substrate entrance tunnel and modeling of a complex structure with Galbeta(1,3)NAG enabled us to assign three key residues to the specific catalysis. Site-directed mutagenesis in combination with activity assays further proved that residues Trp240 and Tyr455 contribute to stabilizing the N-acetylglucosamine moiety, whereas Trp243 is critical for fixing the galactose ring. Moreover, we propose that BgaC and other galactosidases in the GH-35 family share a common domain organization and a conserved substrate-determinant aromatic residue protruding from the second domain. | |||
Structural insights into the substrate specificity of Streptococcus pneumoniae beta(1,3) galactosidase BgaC.,Cheng W, Wang L, Jiang YL, Bai XH, Chu J, Li Q, Yu G, Liang QL, Zhou CZ, Chen Y J Biol Chem. 2012 May 16. PMID:22593580<ref>PMID:22593580</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4e8d" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Galactosidase 3D structures|Galactosidase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Streptococcus pneumoniae TIGR4]] | |||
[[Category: Bai XH]] | |||
[[Category: Chen YX]] | |||
[[Category: Cheng W]] | |||
[[Category: Jiang YL]] | |||
[[Category: Li Q]] | |||
[[Category: Wang L]] | |||
[[Category: Yu G]] | |||
[[Category: Zhou CZ]] | |||