View source for 9pno


==Crystal structure of the Streptococcus pneumoniae HtrA protease PDZ domain==
<StructureSection load='9pno' size='340' side='right'caption='[[9pno]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9pno]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9PNO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9PNO 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]] 1.85&#8491;</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=9pno FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9pno OCA], [https://pdbe.org/9pno PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9pno RCSB], [https://www.ebi.ac.uk/pdbsum/9pno PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9pno ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A4J2AIC8_STREE A0A4J2AIC8_STREE] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
High-temperature requirement A (HtrA) proteases are a conserved family of serine proteases central to protein quality control and bacterial virulence. While Gram-negative and human HtrAs are structurally well studied, Gram-positive homologs remain essentially uncharacterized. Here, we present the first integrated structural and mechanistic analysis of a Gram-positive HtrA, from Streptococcus pneumoniae, a virulence factor essential for adhesion and infection in vivo. Proteomic profiling of an htrA knockout and cleavage assays demonstrate that S. pneumoniae HtrA is required for protein quality control, with the PDZ domain mediating substrate recognition. Biochemically, S. pneumoniae HtrA exists exclusively as a monomer in solution, a striking divergence from canonical trimeric HtrAs that we show is shared with other Gram-positive homologs. NMR analyses reveal that the monomer dynamically samples open and closed conformations, while cryo-EM of a catalytic mutant identifies a hexamer stabilized by a unique LoopA-PDZ interaction. Together, these findings define S. pneumoniae HtrA as a dynamic monomer with interdomain coupling between its protease and PDZ domains, establishing Gram-positive HtrAs as a mechanistically divergent subgroup within the HtrA family.

Streptococcus pneumoniae HtrA is a dynamic and monomeric virulence factor capable of forming larger oligomeric complexes.,Lee E, Redzic JS, Gordon B, Saviola AJ, Tran N, Maroney SP, Ashby NL, Shaw S, Fulte S, McCarty A, Holyoak T, Meyer N, Hansen KC, Clark SE, Eisenmesser E Protein Sci. 2026 Jan;35(1):e70411. doi: 10.1002/pro.70411. PMID:41457497<ref>PMID:41457497</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9pno" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Streptococcus pneumoniae]]
[[Category: Holyoak T]]
[[Category: Tran N]]