Mapping the Yeast 19S Proteasome Topology by Chemical Cross-linking and Multistage Tandem Mass Spectrometry

摘要

Dynamic interactions of multi-subunit protein complexes are required to maintain normal cellular homeostasis. Understanding the interactions of protein complexes would be fundamental in discovering regulation in metabolic pathways, thus having a wide application in disease research and drug discovery. The 26S proteasome is a critical multi-subunit protein complex involved in ubiquitin-mediated protein degradation. This megadalton complex is comprised of two copies of at least 33 subunits, in which proteins marked for degradation by polyubiquitination are recognized, unfolded, and proteolytically cleaved. The 26S proteasome is composed of a 20S catalytic sub-complex, with known crystal structure, and up to two 19S regulatory sub-complexes. The 19S structure and topology remains largely vague due to its dynamic behavior.