Fig. 1.

(A) Structure of the human 9-1-1 complex. The crystal structure 91-272-1-1 is shown (RCSB codes:3A1J) [30]. The structure of the extreme C-terminal domain of Rad9 (Rad9Cter) has not been determined. The key differences among the three subunits are circled in red. The DNA in the channel of the 9-1-1 ring is tilted toward Rad9 and the N-terminal domain of Hus1 based on the data from this paper. (B) Structure of Hus1 showing the locations of K136 and V137 based on the structure of 91-272-Rad1-Hus1 (RCSB codes:3A1J) [30]. N and C indicate N- and C-termini, respectively.