Table 1:
Summary of PISA predicted and experimentally observed CL-MS changes for residues in the P3, P4, and P5 domains of CheA.
| Residue | Predicted labeling change (interface location)1 | Observed labeling change |
|---|---|---|
| His300 | None | None |
| Tyr331 | Change2 (CheA dimer interface) |
Decrease |
| Thr375/His3763 | None | None |
| Ser381/His3843 | Decrease4 | Decrease |
| Ser399 | None | None |
| Lys479 | None | None |
| His488 | None | None |
| His543 | Decrease (interface 2 with CheW) |
Decrease |
| Tyr614 | Decrease (interface 1 with CheW) |
None |
| Lys616 | Decrease (interface 1 with CheW) |
None |
1
Predictions are largely based on PISA analysis of the structural model to identify residues present at a new interface in the complex. See text for details.
2
Tyr331 is in the P3–4 connecting segment which is thought to be repositioned upon kinase activation, and thus is likely repositioned in the kinase-on complexes studied here.
3
The MS/MS data are not definitive enough to allow the exact labeled residue to be identified in peptides containing these residues.
4
These residues are in the ATP binding site. His384 changes positions in the complex, making it less exposed.