Hyperthermostable acetyl xylan esterase.
Bottom Line: Thermotoga maritima AxeA represents the most thermostable acetyl xylan esterase known to date.Differential scanning calorimetry analysis of the thermal stability of AxeA corroborated its extreme heat resistance.A multi-phasic unfolding behaviour was found, with two apparent exothermic peaks at approximately 100-104 °C and 107.5 °C.
Affiliation: Institut f. Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, D-37077 Goettingen, Germany.Show MeSH
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Mentions: The thermal stability of AxeA was further investigated by differential scanning calorimetry (DSC). The observed unfolding transition was characterized by two apparent exothermic peaks, a broad one in the range between 100°C and 104°C, and a sharp one at 107.5°C (Fig. 5), which testifies to the extremely high thermostability of the enzyme. The deconvolution of the multi‐phasic unfolding behaviour yielded at least three intermediates, in accordance with the complex structure of AxeA (Fig. 2). However, an unambiguous assignment of the transitions to the denaturation or dissociation of the subunits of the oligomer was not possible. At higher temperatures an endothermic signal was observed, which is probably due to protein aggregation following denaturation. In accordance with this assumption, no signal was observed when reheating the sample after cooling.
Affiliation: Institut f. Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, D-37077 Goettingen, Germany.