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-Structure paper
Title | Structure of the proteolytic enzyme PAPP-A with the endogenous inhibitor stanniocalcin-2 reveals its inhibitory mechanism. |
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Journal, issue, pages | Nat Commun, Vol. 13, Issue 1, Page 6084, Year 2022 |
Publish date | Oct 18, 2022 |
Authors | Sara Dam Kobberø / Michael Gajhede / Osman Asghar Mirza / Søren Kløverpris / Troels Rønn Kjær / Jakob Hauge Mikkelsen / Thomas Boesen / Claus Oxvig / |
PubMed Abstract | The metzincin metalloproteinase PAPP-A plays a key role in the regulation of insulin-like growth factor (IGF) signaling by specific cleavage of inhibitory IGF binding proteins (IGFBPs). Using single- ...The metzincin metalloproteinase PAPP-A plays a key role in the regulation of insulin-like growth factor (IGF) signaling by specific cleavage of inhibitory IGF binding proteins (IGFBPs). Using single-particle cryo-electron microscopy (cryo-EM), we here report the structure of PAPP-A in complex with its endogenous inhibitor, stanniocalcin-2 (STC2), neither of which have been reported before. The highest resolution (3.1 Å) was obtained for the STC2 subunit and the N-terminal approximately 1000 residues of the PAPP-A subunit. The 500 kDa 2:2 PAPP-A·STC2 complex is a flexible multidomain ensemble with numerous interdomain contacts. In particular, a specific disulfide bond between the subunits of STC2 and PAPP-A prevents dissociation, and interactions between STC2 and a module located in the very C-terminal end of the PAPP-A subunit prevent binding of its main substrate, IGFBP-4. While devoid of activity towards IGFBP-4, the active site cleft of the catalytic domain is accessible in the inhibited PAPP-A·STC2 complex, as shown by its ability to hydrolyze a synthetic peptide derived from IGFBP-4. Relevant to multiple human pathologies, this unusual mechanism of proteolytic inhibition may support the development of specific pharmaceutical agents, by which IGF signaling can be indirectly modulated. |
External links | Nat Commun / PubMed:36257932 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.06 - 5.02 Å |
Structure data | EMDB-15217: PAPP-A dimer in complex with a dimer of the inhibitor STC2 EMDB-15219: PAPP-A dimer in complex with endogenous STC2 inhibitor. EMDB-15220, PDB-8a7d: EMDB-15221: PAPP-A dimer in complex with its inhibitor STC2 (CASP target) |
Chemicals | ChemComp-NAG: ChemComp-ZN: ChemComp-CA: |
Source |
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Keywords | HYDROLASE / Metzincin metalloprotease Inhibitor complex |