Molecular determinants of complex formation between Clp/Hsp100 ATPases and the ClpP peptidase.
The Clp/Hsp100 ATPases are hexameric protein machines that catalyze the unfolding, disassembly and disaggregation of specific protein substrates in bacteria, plants and animals. Many family members also interact with peptidases to form ATP-dependent proteases. In Escherichia coli, for instance, the ClpXP protease is assembled from the ClpX ATPase and the ClpP peptidase. Here, we have used multiple sequence alignments to identify a tripeptide 'IGF' in E. coli ClpX that is essential for ClpP recognition. Mutations in this IGF sequence, which appears to be part of a surface loop, disrupt ClpXP complex formation and prevent protease function but have no effect on other ClpX activities. Homologous tripeptides are found only in a subset of Clp/Hsp100 ATPases and are a good predictor of family members that have a ClpP partner. Mapping of the IGF loop onto a homolog of known structure suggests a model for ClpX-ClpP docking.
Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Y I
YI
Kim
I
I
Levchenko
K
K
Fraczkowska
R V
RV
Woodruff
R T
RT
Sauer
T A
TA
Baker
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D049071:Endopeptidase Clp; D010450:Endopeptidases / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D010450:Endopeptidases; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483573:ClpXP protease, E coli; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C095049:ClpB protein, Leishmania