Of particular importance is a so-called LPXP motif within the receptor subunit that forms a minor yet crucial supplementary interaction with the Cullin NTD [ 21].
This might account for the observed enrichment of the human PIN in archaebacterial archaebacterial, eubacterial eubacterial, and ESP ESP interactions (supplementary table S7, Supplementary Material online; fig. 1).
Comparison of these numbers with those obtained from a set of 10,000 randomized networks (see Methods) shows that they are significantly higher than expected at random (P < 2 × 10−4 for the archaebacterial archaebacterial, eubacterial eubacterial, and ESP ESP interactions; supplementary table S7, Supplementary Material online; fig. 1).
We filtered the PIN1 network by removing self-interactions (giving rise to the PIN2 network, consisting of 8,280 proteins connected by 29,611 interactions; supplementary fig. S1, Supplementary Material online) and both self-interactions and interactions among proteins encoded by paralogous genes (PIN3, 8,189 proteins and 29,059 interactions; supplementary fig. S1, Supplementary Material online).
For confirmation, we generated a subnetwork of PIN3 containing only proteins encoded by genes with prokaryotic homologs (PIN3prok, 3,031 proteins and 6,666 interactions; supplementary fig. S1, Supplementary Material online).
Importantly, loss of Leu-954 results in a distinct conformation of the extended coil that precedes α-helix H1' (Figure 2B) and this directs unique intramolecular interactions (Supplementary Figure S7).
for their ability to promote PYR1-HAB1 interactionSupplementaryary information, Figure S1).
Lines are fits to a model of receptor-ligand cis- interactions (Supplementary).
As a result, Asp168 shifts toward Arg123 for electrostatic interactions (Supplementary Figure S1b).
Control experiments using GST alone revealed no detectable interactions (Supplementary Figure 4e).
