Architectural and thermodynamic principles underlying intramembrane protease function

Intramembrane proteases hydrolyze peptide bonds within the membrane as a signaling paradigm universal to all life forms and with implications in disease. Deciphering the architectural strategies supporting intramembrane proteolysis is an essential but unattained goal. We integrated a new, quantitati...

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Detalles Bibliográficos
Autores principales: Baker, Rosanna P., Urban, Sinisa
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028635/
https://www.ncbi.nlm.nih.gov/pubmed/22797666
http://dx.doi.org/10.1038/nchembio.1021
Descripción
Sumario:Intramembrane proteases hydrolyze peptide bonds within the membrane as a signaling paradigm universal to all life forms and with implications in disease. Deciphering the architectural strategies supporting intramembrane proteolysis is an essential but unattained goal. We integrated a new, quantitative and high-throughput thermal light-scattering technology, reversible equilibrium un/refolding, and quantitative protease assays to interrogate rhomboid architecture with 151 purified variants. Rhomboid proteases maintain low intrinsic thermodynamic stability (ΔG=2.1-4.5kcal/mol) resulting from a multitude of generally-weak transmembrane packing interactions, making them highly-responsive to their environment. Stability is consolidated by two buried glycines and several packing leucines, with a few multifaceted hydrogen bonds strategically-deployed to two peripheral regions. Opposite these regions lie transmembrane segment 5 and connected loops that are notably exempt of structural responsibility, suggesting intramembrane proteolysis involves considerable but localized protein dynamics. Our analyses provide a comprehensive ‘heat map’ of the physio-chemical anatomy underlying membrane-immersed enzyme function at unprecedented resolution.