1MBU: Crystal Structure Analysis Of Clpsn Heterodimer

Substrate selectivity and proteolytic activity for the E. coli ATP-dependent protease, ClpAP, is modulated by an adaptor protein, ClpS. ClpS binds to ClpA, the regulatory component of the ClpAP complex. We report the crystal structure of ClpS in complex with the isolated N-terminal domain of ClpA in two different crystal forms at 2.3- and 3.3-A resolution. The ClpS structure forms an alpha/beta-sandwich and is topologically analogous to the C-terminal domain of the ribosomal protein L7/L12. ClpS contacts two surfaces on the N-terminal domain in both crystal forms; the more extensive interface was shown to be favored in solution by protease protection experiments. The N-terminal 20 residues of ClpS are not visible in the crystal structures; the removal of the first 17 residues produces ClpSDeltaN, which binds to the ClpA N-domain but no longer inhibits ClpA activity. A zinc binding site involving two His and one Glu residue was identified crystallographically in the N-terminal domain of ClpA. In a model of ClpS bound to hexameric ClpA, ClpS is oriented with its N terminus directed toward the distal surface of ClpA, suggesting that the N-terminal region of ClpS may affect productive substrate interactions at the apical surface or substrate entry into the ClpA translocation channel.
PDB ID: 1MBUDownload
MMDB ID: 21448
PDB Deposition Date: 2002/8/3
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 1MBU: dimeric; determined by author and by software (PISA)
Molecular Components in 1MBU
Label Count Molecule
Proteins (2 molecules)
Atp-dependent CLP Protease Atp-binding Subunit CLP a(Gene symbol: clpA)
Molecule annotation
Protein Ylja(Gene symbol: clpS)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB