Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Structural basis for dimerization, catalytic regulation, and substrate selectivity of the chloroplast S9D CGEP protease in Arabidopsis thaliana.
Journal, issue, pages	Protein Sci, Vol. 35, Issue 6, Page e70624, Year 2026
Publish date	May 18, 2026
Authors	Jacqueline J Ehrlich / Pratyush Routray / Louis Enns / Klaas J van Wijk / Toshimitsu Kawate /
PubMed Abstract	S9 proteases are widely distributed across the tree-of-life and play essential roles in protein processing. However, the structural and mechanistic basis for protease activity in the S9D subfamily, ...S9 proteases are widely distributed across the tree-of-life and play essential roles in protein processing. However, the structural and mechanistic basis for protease activity in the S9D subfamily, restricted to photosynthetic eukaryotes (e.g., plants), cyanobacteria, proteobacteria and flavobacteria, is unknown. Here, we report the first high-resolution cryo-EM structures of an S9D protease, chloroplast glutamyl endopeptidase (CGEP) from the model plant Arabidopsis thaliana. CGEP adopts a dimeric architecture stabilized by two distinct interfaces: hydrophobic interactions between catalytic domains and an interdomain β-sheet linking the cap and catalytic domains. These interactions create a scaffold that supports a hinge loop, which acts as a steric gate to restrict substrate access and confine catalytic activity to the closed conformation. Unlike S9A-B-C proteases, CGEP maintains an intact catalytic triad in both open and closed states, relying on hinge-loop gating rather than catalytic disruption for regulation. Structural analysis and mutagenesis reveal that the hinge loop forms a conserved pocket favoring glutamate side chains, explaining CGEP's strong glutamate preference at cleavage sites. Together, these findings uncover a unique regulatory paradigm for S9D proteases and provide a structural framework for understanding substrate selectivity and dimerization.
External links	Protein Sci / PubMed:42144868 / PubMed Central
Methods	EM (single particle)
Resolution	3.0 - 3.3 Å
Structure data	75113 10eo EMDB-75113, PDB-10eo: Chloroplast Glutamyl Peptidase S781R in closed-closed conformation Method: EM (single particle) / Resolution: 3.2 Å 75114 10ep EMDB-75114, PDB-10ep: Chloroplast Glutamyl Peptidase S781R in open-closed conformation Method: EM (single particle) / Resolution: 3.2 Å 75115 10eq EMDB-75115, PDB-10eq: Chloroplast Glutamyl Peptidase WT in open-closed conformation Method: EM (single particle) / Resolution: 3.3 Å 75116 10er EMDB-75116, PDB-10er: Chloroplast Glutamyl Peptidase S781R in open-open conformation Method: EM (single particle) / Resolution: 3.2 Å 75117 10es EMDB-75117, PDB-10es: Chloroplast Glutamyl Peptidase WT in open-open conformation Method: EM (single particle) / Resolution: 3.0 Å 75118 10et EMDB-75118, PDB-10et: Chloroplast Glutamyl Peptidase D855N in open-closed conformation Method: EM (single particle) / Resolution: 3.0 Å 75119 10eu EMDB-75119, PDB-10eu: Chloroplast Glutamyl Peptidase D855N in open-open conformation Method: EM (single particle) / Resolution: 3.0 Å
Source	arabidopsis thaliana (thale cress)
Keywords	PLANT PROTEIN / S9 protease / enzyme / serine protease / alpha-beta-alpha sandwich fold / beta-propeller