Crystal structure of the human 20S proteasome in complex with carfilzomib

Area of Science:

• Biochemistry
• Structural Biology
• Pharmacology

Background:

• Proteasome inhibitors are crucial for multiple myeloma treatment.
• Carfilzomib is an FDA-approved proteasome inhibitor for relapsed/refractory multiple myeloma.

Purpose of the Study:

• To determine the X-ray crystal structure of the human constitutive 20S proteasome with and without carfilzomib.
• To elucidate the structural basis for carfilzomib's selectivity.
• To compare human and mouse proteasome structures for inhibitor design.

Main Methods:

• X-ray crystallography of human constitutive 20S proteasome.
• Structural comparison with mouse immunoproteasome and proteasome-inhibitor complexes.

Main Results:

• The crystal structure of the human constitutive 20S proteasome with and without carfilzomib was determined.
• The S3 and S4 binding pockets are key to carfilzomib's selectivity for chymotrypsin-like sites.
• Amino acid differences explain carfilzomib's preference for constitutive proteasomes over immunoproteasomes.

Conclusions:

• Structural data support the rational design of selective proteasome inhibitors.
• These findings have implications for treating cancers, autoimmune diseases, and neurodegenerative disorders.