Characterization of the interaction between superoxide dismutase and 2-oxoisovalerate dehydrogenase

• The proteins interacted with SOD was characterized in Thermus thermophilus.
• Based on Co-IP with SOD antibody, DHα was found to bind to SOD.
• The binding was confirmed by Western blot, bacterial two-hybrid assays and ITC.
• The existence of an interaction between SOD and full-length DHα was revealed.
• Our study presented a novel aspect of SOD in thermoadaptation of thermophiles.

Thermophiles are attractive microorganisms to study the adaptation of life in high temperature environment. It is revealed that superoxide dismutase (SOD) is essential for thermoadaptation of thermophiles. However, the SOD-mediated pathway of thermoadaptation remains unclear. To address this issue, the proteins interacted with SOD were characterized in Thermus thermophilus in this study. Based on co-immunoprecipitation and Western blot analyses, the results showed that 2-oxoisovalerate dehydrogenase α subunit was bound to SOD. The isothermal titration calorimetry analysis showed the existence of the interaction between SOD and 2-oxoisovalerate dehydrogenase α subunit. The bacterial two-hybrid data indicated that SOD was directly interacted with 2-oxoisovalerate dehydrogenase α subunit. Gene site-directed mutagenesis analysis revealed that the intracellular interaction between SOD and 2-oxoisovalerate dehydrogenase α subunit was dependent on their whole molecules. Therefore our study presented a novel aspect of SOD in the thermoadaptation of thermophiles by interaction with dehydrogenase, a key enzyme of tricarboxylic acid cycle.