Interaction of TIP26 from a hyperthermophilic archaeon with TFB/TBP/DNA ternary complex

Interactions of TBP-interacting protein (TIP26), TBP, and TFB from a hypert hermophilic archaeon Thermococcus kodakaraensis KOD1 with TATA-DNA were exa mined by electrophoretic mobility shift assay. Tk-TFB formed a ternary comp lex with Tk-TBP and TATA-DNA. Tk-TIP26 did not inhibit the formation of thi s ternary complex, but interacted with it to form a TIP26/TFB/TBP/DNA quate rnary complex. This interaction is rather weak, and a large excess of Tk-TI P26 over Tk-TBP is required to fully convert the TFB/TBP/DNA ternary comple x to the quaternary complex. However, determination of the concentration of Tk-TIP26 and Tk-TBP in KOD1 cells by Western blotting analysis indicated t hat the concentration of Tk-TIP26 is approximately ten times that of Tk-TBP , suggesting that the quaternary complex might also form in vivo.