Work

Roles of the ClpX IGF loops in ClpP association, dissociation, and protein degradation

Year: 2019

Type: article

Abstract: IGF-motif loops project from the hexameric ring of ClpX and are required for docking with the self-compartmentalized ClpP peptidase, which consists of heptameric rings stacked back-to-back. Here, we show that ATP or ATPγS support assembly by changing the conformation of the ClpX ring, bringing the IGF loops closer to each other and allowing efficient multivalent contacts with docking clefts on ClpP. In single-chain ClpX pseudohexamers, deletion of one or two IGF loops modestly slows association with ClpP but strongly accelerates dissociation of ClpXP complexes. We probe how changes in the sequence and length of the IGF loops affect ClpX-ClpP interactions and show that deletion of one or two IGF loops slows ATP-dependent proteolysis by ClpXP. We also find that ClpXP degradation is less processive when two IGF loops are deleted.

Source: Protein Science

DOI: 10.1002/pro.3590

Authors: Alvaro J. Amor, Karl R. Schmitz, Tania A. Baker, Robert T. Sauer

Institutions: Massachusetts Institute of Technology, Howard Hughes Medical Institute

Language: English

Topic: Heat shock proteins research

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: bronze

Funders: Howard Hughes Medical Institute, Charles A. King Trust, National Institutes of Health, National Institute of General Medical Sciences

Awards: Sequence Determinants of Protein Structure and Stability, Pre-Doctoral Training in Biological Sciences