FIG. 1.

Deduced and experimentally determined N-terminal sequences of the M. thermophila 20S proteasome α and β subunits. PsmA and PsmB, α subunit and β prosubunit sequences deduced from the psmA and psmB gene sequences shown in uppercase letters; α-1 and α-2, experimentally determined sequences of the α subunit from the authentic 20S proteasome purified directly from M. thermophila; α-3, experimentally determined sequence of the α subunit produced in E. coli either independently or in the 20S proteasome; β-1, experimentally determined sequence obtained for either the mature β subunit from the authentic 20S proteasome or the mature β subunits from the heterologously produced 20S proteasomes assembled either in vivo or in vitro; β-2, experimentally determined sequence of the β prosubunit independently produced in E. coli. X, uncertain amino acid assignment. The bases in boldface are putative ribosome binding sites.