3G1B

The structure of the M53A mutant of Caulobacter crescentus clpS protease adaptor protein in complex with WLFVQRDSKE peptide

Summary for 3G1B

• Entry DOI: 10.2210/pdb3g1b/pdb
• Related: 3dnj 3g19
• Descriptor: ATP-dependent Clp protease adapter protein clpS, 10-residue peptide, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: adaptor, protein-peptide complex, peptide-binding protein, peptide binding protein
• Biological source: Caulobacter vibrioides (Caulobacter vibrioides); More
• Total number of polymer chains: 4
• Total formula weight: 22436.01

Authors

Baker, T.A.,Roman-Hernandez, G.,Sauer, R.T.,Grant, R.A. (deposition date: 2009-01-29, release date: 2009-04-28, Last modification date: 2023-09-06)

Primary citation

Roman-Hernandez, G.,Grant, R.A.,Sauer, R.T.,Baker, T.A.
Molecular basis of substrate selection by the N-end rule adaptor protein ClpS.
Proc.Natl.Acad.Sci.USA, 106:8888-8893, 2009

PubMed Abstract: The N-end rule is a conserved degradation pathway that relates the stability of a protein to its N-terminal amino acid. Here, we present crystal structures of ClpS, the bacterial N-end rule adaptor, alone and engaged with peptides containing N-terminal phenylalanine, leucine, and tryptophan. These structures, together with a previous structure of ClpS bound to an N-terminal tyrosine, illustrate the molecular basis of recognition of the complete set of primary N-end rule amino acids. In each case, the alpha-amino group and side chain of the N-terminal residue are the major determinants of recognition. The binding pocket for the N-end residue is preformed in the free adaptor, and only small adjustments are needed to accommodate N-end rule residues having substantially different sizes and shapes. M53A ClpS is known to mediate degradation of an expanded repertoire of substrates, including those with N-terminal valine or isoleucine. A structure of Met53A ClpS engaged with an N-end rule tryptophan reveals an essentially wild-type mechanism of recognition, indicating that the Met(53) side chain directly enforces specificity by clashing with and excluding beta-branched side chains. Finally, experimental and structural data suggest mechanisms that make proteins with N-terminal methionine bind very poorly to ClpS, explaining why these high-abundance proteins are not degraded via the N-end rule pathway in the cell.

PubMed: 19451643
DOI: 10.1073/pnas.0903614106

Experimental method

X-RAY DIFFRACTION (1.448 Å)