Lon 蛋白酵素對類組織蛋白HU降解之探討
ATP-dependent degradation in Vitro of histone-like HU protein from Bacillus subtilis by Lon protease
Date Issued
2004
Date
2004
Author(s)
Chen, Tse-An
DOI
en-US
Abstract
HU, a prokaryotic histone-like protein, associates with bacterial nucleoids and plays architectural roles in replication initiation, transcription regulation and site-specific recombination. To gain an insight into the role of Lon protease in regulation of HU, the purified Bt-Lon was incubated with HU of Bacillus subtilis (Bs-HU). Lon selectively degraded Bs-HU in an ATP-dependent manner, thus confirming the ability of Lon to directly recognize and degrade specific substrates. Cleavage occurred at Leu44-Ile45 and Ala57-Arg58 peptide bonds in the early period of degradation, which are known to be in the DNA-binding motif of Bs-HU. Plasmid DNA and ds-DNA can both enhance proteolysis, with plasmid being better enhancer than ds-DNA .
In addition, the degradation of Bs-HU by Bt-Lon in the early period does not influence its ability to bind single-stranded DNA even removing the DNA-binding motif; however, the degradation causes the loss of the DNA-binding ability after incubation with Bt-Lon for 2 h. Furthermore, the DNA conformation altered by Hu can be reformed from the degradation of HU by Bt-Lon. This is the first example to show that HU, a DNA binding protein, is a physiological substrate of Lon protease and Lon protease is probably involved in the regulation of gene expression by degradation of HU.
Subjects
DNA結合蛋白
Lon蛋白
HU蛋白
HU protein
Lon protein
DNA binding protein
Type
other
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