Proteomic analysis on the temperature-dependent complexes in Thermoanaerobacter tengcongensis

It is generally accepted that protein complexes play an active role in avoiding the protein degradation of the thermophiles. Thermoanaerobacter tengcongensis was cultured at three different temperatures (55, 75 and 80°C) and the extracts of protein complexes were prepared. Through blue native PAGE, the changes of the relative band volumes in response to different temperatures were semi-quantitatively compared and six temperature-dependent bands were obtained. These bands were excised, digested with trypsin and then analyzed with MS for the identification of protein components. With the combination of the proteins identified by LC MS/MS and MALDI TOF/TOF MS, a total of 92 unique proteins were ascertained in these complexes. Besides, some protein components were examined with Western blot, which gave us insights into the survival mechanism of thermophiles. These included (i) the composition of complex at 80°C was significantly different from that at the other two temperatures; (ii) HSPs presented in all temperature-dependent complexes; (iii) several proteins associated with the functional pathways existed in the same complexes, indicating that the complex structure provided facility for the functional efficiency.