Protein Variants | Comment | Organism |
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additional information | the combined absence of Lon and SecB leads to a significant increase in protein aggregation at 37°C. The most abundant aggregated species are proteins destined for export. Data suggest that Lon and SecB share some substrates and that the SecB chaperone protects them from Lon degradation at both high and low temperatures | Escherichia coli |
S679A | complete loss of activity. Mutant is not capable of restoring the secB cold sensitive phenotype, indicating that the deleterious effect of Lon in the secB mutant is due to its protease activity | Escherichia coli |
Organism | UniProt | Comment | Textmining |
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Escherichia coli | - |
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General Information | Comment | Organism |
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physiological function | the Lon protease and the SecB and DnaJ/Hsp40 chaperones are involved in the quality control of presecretory proteins in Escherichia coli. Mutations in the lon gene alleviate the cold-sensitive phenotype of a secB mutant. In comparison to the respective single mutants, the double secB lon mutant strongly accumulates aggregates of SecB substrates at physiological temperatures, suggesting that the chaperone and the protease share substrates. The main substrates identified in secB lon aggregates, namely proOmpF and proOmpC, are highly sensitive to specific degradation by Lon. In contrast, both substrates are significantly protected from Lon degradation by SecB. The chaperone DnaJ by itself protects substrates better from Lon degradation than SecB or the complete DnaK/DnaJ/GrpE chaperone machinery | Escherichia coli |