3gpt
From Proteopedia
Crystal structure of the yeast 20S proteasome in complex with Salinosporamide derivatives: slow substrate ligand
Structural highlights
FunctionPSA2_YEAST The proteasome degrades poly-ubiquitinated proteins in the cytoplasm and in the nucleus. It is essential for the regulated turnover of proteins and for the removal of misfolded proteins. The proteasome is a multicatalytic proteinase complex that is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. It has an ATP-dependent proteolytic activity. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMany marketed drugs contain fluorine, reflecting its ability to modulate a variety of biological responses. The unique 20S proteasome inhibition profile of fluorosalinosporamide compared to chlorinated anticancer agent salinosporamide A (NPI-0052) is exemplary and relates to each halogen's leaving group potential. Crystal structures of fluoro-, hydroxy-, and bromosalinosporamide in complex with the yeast 20S proteasome core particle (CP) provide mechanistic insights into ligand binding and leaving group elimination and the ability to fine-tune the duration of proteasome inhibition. Fluorosalinosporamide/CP crystal structures determined over time offer striking snapshots of the ligand trapped with an intact fluoroethyl group in anticipation of fluoride elimination, followed by complete nucleophilic displacement of fluoride to give the highly stabilized cyclic ether found for salinosporamide A and bromosalinosporamide. This two-step reaction pathway is consistent with a mechanism for partially reversible proteasome inhibition by fluorosalinosporamide. Proteasome catalyzed fluoride displacement provides preliminary insights into the active site Thr1N pK(a). Snapshots of the fluorosalinosporamide/20S complex offer mechanistic insights for fine tuning proteasome inhibition.,Groll M, McArthur KA, Macherla VR, Manam RR, Potts BC J Med Chem. 2009 Sep 10;52(17):5420-8. PMID:19678642[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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