6xry

Publication Abstract from PubMed

The polar organizing protein Z (PopZ) is necessary for the formation of three-dimensional microdomains at the cell poles in Caulobacter crescentus, where it functions as a hub protein that recruits multiple regulatory proteins from the cytoplasm. Although a large portion of the protein is predicted to be natively unstructured, in reconstituted systems PopZ can self-assemble into a macromolecular scaffold that directly binds to at least ten different proteins. Here we report the solution NMR structure of PopZ(Delta134-177), a truncated form of PopZ that does not self-assemble but retains the ability to interact with heterologous proteins. We show that the unbound form of PopZ(Delta134-177) is unstructured in solution, with the exception of a small amphipathic alpha-helix in residues M10-I17, which is included within a highly conserved region near the N-terminus. In applying NMR techniques to map the interactions between PopZ(Delta134-177) and one of its binding partners, RcdA, we find evidence that the alpha-helix and adjoining amino acids extending to position E23 serve as the core of the binding motif. Consistent with this, a point mutation at position I17 severely compromises binding. Our results show that a partially structured Molecular Recognition Feature (MoRF) within an intrinsically disordered domain of PopZ contributes to the assembly of polar microdomains, revealing a structural basis for complex network assembly in Alphaproteobacteria that is analogous to those formed by intrinsically disordered hub proteins in other kingdoms.

Intrinsically disordered bacterial polar organizing protein Z, PopZ, interacts with protein binding partners through an N-terminal Molecular Recognition Feature.,Nordyke CT, Ahmed Y, Puterbaugh RZ, Bowman GR, Varga K J Mol Biol. 2020 Oct 12. pii: S0022-2836(20)30571-4. doi:, 10.1016/j.jmb.2020.09.020. PMID:33058876^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.