Structural changes induced by ligand ‐binding drastically increase the thermostability of the Ser/Thr protein kinase TpkD from Thermus thermophilus HB8

AbstractThermophilic proteins maintain their structure at high temperatures through a combination of various factors.  Here, we report the ligand‐induced stabilization of a thermophilic Ser/Thr protein kinase.  Thermus thermophilus TpkD unfolds completely at 55°C despite the optimum growth temperature of 75°C. Unexpectedly, we found that the TpkD structure is drastically stabilized by its natural ligands ATP and ADP, as evidenced by the increase in the melting temperature to 80°C. Such a striking effect of a substra te on thermostability has not been reported for other protein kinases. Conformational changes upon ATP binding were observed in fluorescence quenching and limited proteolysis experiments. Urea denaturation of Trp mutants suggested that ATP binding affects not only the ATP‐binding site, but also t he remote regions. Our findings shed light on thermoadaptation of thermophilic proteins.

Source: FEBS Letters - November 7, 2020 Category: Biochemistry Authors: Yusuke Fujino, Takero Miyagawa, Masayuki Torii, Masao Inoue, Yuki Fujii, Hiroki Okanishi, Yoshikatsu Kanai, Ryoji Masui Tags: RESEARCH LETTER Source Type: research