View source for 6vu6


==Sialic acid binding region of Streptococcus Sanguinis SK1 adhesin bound to 3'sLn==
<StructureSection load='6vu6' size='340' side='right'caption='[[6vu6]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6vu6]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptococcus_sanguinis_SK1_=_NCTC_7863 Streptococcus sanguinis SK1 = NCTC 7863]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6VU6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6VU6 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=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PRD_900067:3-sialyl-N-acetyllactosamine'>PRD_900067</scene>, <scene name='pdbligand=SIA:O-SIALIC+ACID'>SIA</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=6vu6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6vu6 OCA], [https://pdbe.org/6vu6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6vu6 RCSB], [https://www.ebi.ac.uk/pdbsum/6vu6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6vu6 ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Sialic acid-binding immunoglobulin-like lectins (Siglec)-like domains of streptococcal serine-rich repeat (SRR) adhesins recognize sialylated glycans on human salivary, platelet, and plasma glycoproteins via a YTRY sequence motif. The SRR adhesin from Streptococcus sanguinis strain SK1 has tandem sialoglycan-binding domains and has previously been shown to bind sialoglycans with high affinity. However, both domains contain substitutions within the canonical YTRY motif, making it unclear how they interact with host receptors. To identify how the S. sanguinis strain SK1 SRR adhesin affects interactions with sialylated glycans and glycoproteins, we determined high-resolution crystal structures of the binding domains alone and with purified trisaccharides. These structural studies determined that the ligands still bind at the noncanonical binding motif, but with fewer hydrogen-bonding interactions to the protein than is observed in structures of other Siglec-like adhesins. Complementary biochemical studies identified that each of the two binding domains has a different selectivity profile. Interestingly, the binding of SK1 to platelets and plasma glycoproteins identified that the interaction to some host targets is dominated by the contribution of one binding domain, whereas the binding to other host receptors is mediated by both binding domains. These results provide insight into outstanding questions concerning the roles of tandem domains in targeting host receptors and suggest mechanisms for how pathogens can adapt to the availability of a range of related but nonidentical host receptors. They further suggest that the definition of the YTRY motif should be changed to varphiTRX, a more rigorous description of this sialic acid-recognition motif given recent findings.

Tandem sialoglycan-binding modules in a Streptococcus sanguinis serine-rich repeat adhesin create target dependent avidity effects.,Stubbs HE, Bensing BA, Yamakawa I, Sharma P, Yu H, Chen X, Sullam PM, Iverson TM J Biol Chem. 2020 Oct 23;295(43):14737-14749. doi: 10.1074/jbc.RA120.014177. Epub, 2020 Aug 20. PMID:32820052<ref>PMID:32820052</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6vu6" style="background-color:#fffaf0;"></div>

==See Also==
*[[Adhesin 3D structures|Adhesin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Streptococcus sanguinis SK1 = NCTC 7863]]
[[Category: Iverson TM]]
[[Category: Stubbs HE]]