The Subunit Structure and Dynamics of the 20S Proteasome in Chicken Skeletal Muscle

摘要: We have succeeded in purifying the 20S core proteasome particle from less than 1 g of skeletal muscle a rapid process involving two chromatographic steps. The individual subunits were readily resolved by two-dimensional PAGE, and identities each 14 assigned combination peptide mass fingerprinting MS/MS/de novo sequencing. To assess dynamics biogenesis, chicks fed diet containing stable isotope-labeled valine, rate incorporation label into valine-containing peptides derived subunit was assessed spectrometric analysis after separation. Peptides multiple valine residues other soluble proteins analyzed to yield relative isotope abundance precursor pool, piece information that is essential for calculation turnover parameters. rates synthesis are rather similar, although there evidence high both α (nonproteolytic) β (proteolytic) rings. variability different consistent with model which some produced excess, whereas others may be rate-limiting factor concentration cell. ability measure on proteome-wide scale protein assemblies complex organism provides new dimension understanding dynamic proteome.