An analysis of the effect of changes in growth temperature on proteolysis in vivo in the psychrophilic bacterium Vibrio sp. strain ANT-300

Abstract

In the psychrophilic bacterium Vibrio sp. strain ANT-300, the rate of protein degradation in oiuo? measured at fixed temperatures, increased with elevation of the growth temperature. A shift in growth temperature induced a marked increase in this rate. Dialysed cell-free extracts hydrolysed exogenous insulin, globin and casein (in decreasing order of activity) but did not hydrolyse exogenous cytochrome c. Cells contained at least seven proteases separated by DEAE-Sephacel chromatography, one of which was an ATP-dependent serine protease. The ATP-dependent proteolytic activity in extracts of cells incubated for 3 h at 16 "C after a shift-up from 0 "C increased to a level 36% and 17% higher than that of cells grown at 0 "C and 13 "C, respectively. A shift-down to 0 "C from 13 "C induced only a slight increase in the proteolytic activity. Extracts of all cells, whether exposed to temperature shifts or not, showed the same temperature dependence with respect to both ATP-dependent and ATP-independent protease activity. In all the extracts these proteases also exhibited the same heat lability. The ATP-dependent protease was inactivated by incubation at temperatures above 25 "C. There was an increase in ATP-independent protease activity during incubation at temperatures between 25 and 30 "C, but a decrease at 35 "C and higher. These results suggest that the marked increases in proteolysis in uiuo? caused by a shift in temperature, may result not only from increases in levels of ATP-dependent serine protease(s) but also from increases in the susceptibility of proteins to degradation.

Proteome turnover in bacteria: current status for Corynebacterium glutamicum and related bacteria

“…Subsequently, 79 and 93 proteins were degraded at 30 and 40°C, with thiol-disulfide isomerase and methionine synthase II showing enhanced degradation. Heat-shock, hence, resulted in significantly higher protein degradation rates, as shown previously (Araki, 1992) for other species, too.…”

Protein Turnover Quantification in a Multilabeling Approach: From Data Calculation to Evaluation

“…In our analysis, we found 59.6% of all quantified proteins revealing a slightly increased proteolysis in the heat shocked cells in comparison to 50% under optimal growth conditions. It is assumed that heat stress leads to an elevated degradation of proteins (70), which our results can confirm.…”

The cold shock response of the psychrotrophic bacterium Pseudomonas fragi involves four low-molecular-mass nucleic acid-binding proteins

“…Indeed, the variations were more important (C16.0 and D24.5) and/or happened earlier (C7.0 and C8.0) and/or lasted longer (C7.0, C8.0, C17.0, D24.5, D30.2, E7.0, E8.0, and E31.0) in the 30-to-5°C cold shock. This relationship between the downshift amplitude and protein variations has been observed for other bacteria (1,3,18,31,37) and the psychrotrophic yeast T. pullullans (22). This finding indicates that to cope with cold shock, microorganisms regulate protein expression and particularly a subset of polypeptides which probably play an essential role in the adaptation to low temperature.…”