| Structural highlights
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Function
[HSLU_ECOLI] ATPase subunit of a proteasome-like degradation complex; this subunit has chaperone activity. The binding of ATP and its subsequent hydrolysis by HslU are essential for unfolding of protein substrates subsequently hydrolyzed by HslV. HslU recognizes the N-terminal part of its protein substrates and unfolds these before they are guided to HslV for hydrolysis.[1] [2] [3] [4] [5] [6] [7]
Publication Abstract from PubMed
The HslUV proteolytic machine consists of HslV, a double-ring self-compartmentalized peptidase, and one or two AAA+ HslU ring hexamers that hydrolyze ATP to power the unfolding of protein substrates and their translocation into the proteolytic chamber of HslV. Here, we use genetic-tethering and disulfide-bonding strategies to construct HslU pseudohexamers containing mixtures of ATPase active and inactive subunits at defined positions in the hexameric ring. Genetic tethering impairs HslV binding and degradation, even for pseudohexamers with six active subunits, but disulfide-linked pseudohexamers do not have these defects, indicating that the peptide tether interferes with HslV interactions. Importantly, pseudohexamers containing different patterns of hydrolytically active and inactive subunits retain the ability to unfold protein substrates and/or collaborate with HslV in their degradation, supporting a model in which ATP hydrolysis and linked mechanical function in the HslU ring operate by a probabilistic mechanism.
Covalently Linked HslU Hexamers Support a Probabilistic Mechanism that Links ATP Hydrolysis to Protein Unfolding and Translocation.,Baytshtok V, Chen J, Glynn SE, Nager AR, Grant RA, Baker TA, Sauer RT J Biol Chem. 2017 Feb 21. pii: jbc.M116.768978. doi: 10.1074/jbc.M116.768978. PMID:28223361[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Yoo SJ, Seol JH, Shin DH, Rohrwild M, Kang MS, Tanaka K, Goldberg AL, Chung CH. Purification and characterization of the heat shock proteins HslV and HslU that form a new ATP-dependent protease in Escherichia coli. J Biol Chem. 1996 Jun 14;271(24):14035-40. PMID:8662828
- ↑ Rohrwild M, Coux O, Huang HC, Moerschell RP, Yoo SJ, Seol JH, Chung CH, Goldberg AL. HslV-HslU: A novel ATP-dependent protease complex in Escherichia coli related to the eukaryotic proteasome. Proc Natl Acad Sci U S A. 1996 Jun 11;93(12):5808-13. PMID:8650174
- ↑ Seol JH, Yoo SJ, Shin DH, Shim YK, Kang MS, Goldberg AL, Chung CH. The heat-shock protein HslVU from Escherichia coli is a protein-activated ATPase as well as an ATP-dependent proteinase. Eur J Biochem. 1997 Aug 1;247(3):1143-50. PMID:9288941
- ↑ Kanemori M, Nishihara K, Yanagi H, Yura T. Synergistic roles of HslVU and other ATP-dependent proteases in controlling in vivo turnover of sigma32 and abnormal proteins in Escherichia coli. J Bacteriol. 1997 Dec;179(23):7219-25. PMID:9393683
- ↑ Seong IS, Oh JY, Yoo SJ, Seol JH, Chung CH. ATP-dependent degradation of SulA, a cell division inhibitor, by the HslVU protease in Escherichia coli. FEBS Lett. 1999 Jul 30;456(1):211-4. PMID:10452560
- ↑ Kanemori M, Yanagi H, Yura T. Marked instability of the sigma(32) heat shock transcription factor at high temperature. Implications for heat shock regulation. J Biol Chem. 1999 Jul 30;274(31):22002-7. PMID:10419524
- ↑ Burton RE, Baker TA, Sauer RT. Nucleotide-dependent substrate recognition by the AAA+ HslUV protease. Nat Struct Mol Biol. 2005 Mar;12(3):245-51. Epub 2005 Feb 6. PMID:15696175 doi:10.1038/nsmb898
- ↑ Baytshtok V, Chen J, Glynn SE, Nager AR, Grant RA, Baker TA, Sauer RT. Covalently Linked HslU Hexamers Support a Probabilistic Mechanism that Links ATP Hydrolysis to Protein Unfolding and Translocation. J Biol Chem. 2017 Feb 21. pii: jbc.M116.768978. doi: 10.1074/jbc.M116.768978. PMID:28223361 doi:http://dx.doi.org/10.1074/jbc.M116.768978
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