The Impact of Pyroglutamate: Sulfolobus acidocaldarius Has a Growth Advantage over Saccharolobus solfataricus in Glutamate-Containing Media

Figure 4

Enzymatic activity in crude cell extracts of Sulfolobus acidocaldarius and Saccharolobus solfataricus. Enzymatic activity was calculated for crude cell extracts of S. acidocaldarius MW001 (Saci, red) and S. solfataricus P2 (Sso, grey) supplemented with 2.2 mM L-pyroglutamate and in the presence and absence of 14 mM ATP (+ATP/-ATP) at 65°C for 24 h. Pyroglutamate content differentiated significantly between S. acidocaldarius and S. solfataricus (Wilcoxon–Mann–Whitney test including Benjamini-Hochberg correction, ). Enzymatic activity was calculated based on the pyroglutamate consumption compared to a control without crude cell extract and correlated to the total protein content. One U is defined as the conversion of one μmol pyroglutamate per minute. A sufficient residual ATP content was confirmed after 24 h (data not shown). Values represent the average of four independent cultivations. Error bars represent the standard error between the four experiments.