Figure 3: Real-time NMR monitoring of the phosphorylation of KNL_1–80.

(A) Sequence of WT-KNL1_1–80 with the potential phosphorylation sites indicated; the residues that bind directly to PP1 are underlined. The four residues phosphorylated directly by Aurora B kinase, as observed using NMR spectroscopy, are indicated (Ser24, Ser25, Ser56 and Ser60).

(B) 2D [¹H¹⁵N] HSQC spectra of KNL1_1–80 after the addition of Aurora B kinase. The N-H^N cross peaks of the phosphorylated serines are labeled.

(C) Build-up curves showing the time-course of phosphorylation of KNL1_1–80 by Aurora B Kinase.

(D) KNL1 phosphorylation rates in descending order.

Related to Figure S4–S5.