4e8d: Difference between revisions
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< | ==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: Streptococcus pneumoniae]] | [[Category: Jiang YL]] | ||
[[Category: Bai | [[Category: Li Q]] | ||
[[Category: Chen | [[Category: Wang L]] | ||
[[Category: Cheng | [[Category: Yu G]] | ||
[[Category: Jiang | [[Category: Zhou CZ]] | ||
[[Category: Li | |||
[[Category: Wang | |||
[[Category: Yu | |||
[[Category: Zhou | |||
Latest revision as of 16:46, 8 November 2023
Crystal structure of streptococcal beta-galactosidaseCrystal structure of streptococcal beta-galactosidase
Structural highlights
FunctionPublication Abstract from PubMedThe 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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