Lon and Clp family proteases and chaperones share homologous substrate-recognition domains

AUTOR(ES)

Smith, Catherine K.

FONTE

The National Academy of Sciences

RESUMO

Lon protease and members of the Clp family of molecular chaperones and protease regulatory subunits contain homologous regions with properties expected for substrate-binding domains. Fragments corresponding to these sequences are stably and independently folded for Lon, ClpA, and ClpY. The corresponding regions from ClpB and ClpX are unstable. All five fragments exhibit distinct patterns of binding to three proteins that are protease substrates in vivo: the heat shock transcription factor σ32, the SOS mutagenesis protein UmuD, and Arc repressor bearing the SsrA degradation tag. Recognition of UmuD is mediated through peptide sequences within a 24-residue N-terminal region whereas recognition of both σ32 and SsrA-tagged Arc requires sequences at the C terminus. These results indicate that the Lon and Clp proteases use the same mechanism of substrate discrimination and suggest that these related ATP-dependent bacterial proteases scrutinize accessible or disordered regions of potential substrates for the presence of specific targeting sequences.

Documentos Relacionados

• Here’s the hook: Similar substrate binding sites in the chaperone domains of Clp and Lon
• GB virus B and hepatitis C virus NS3 serine proteases share substrate specificity.
• Viral cysteine proteases are homologous to the trypsin-like family of serine proteases: structural and functional implications.
• Structural basis of N-end rule substrate recognition in Escherichia coli by the ClpAP adaptor protein ClpS
• The Clp proteins: proteolysis regulators or molecular chaperones?