1Z1V

NMR structure of the Saccharomyces cerevisiae Ste50 SAM domain

Summary for 1Z1V

• Entry DOI: 10.2210/pdb1z1v/pdb
• Related: 1UQV
• Descriptor: STE50 protein (1 entity in total)
• Functional Keywords: all helix protein, sam domain, cell cycle
• Biological source: Saccharomyces cerevisiae (baker's yeast)
• Total number of polymer chains: 1
• Total formula weight: 9309.66

Authors

Kwan, J.J.,Warner, N.,Maini, J.,Pawson, T.,Donaldson, L.W. (deposition date: 2005-03-06, release date: 2006-02-14, Last modification date: 2024-05-22)

Primary citation

Kwan, J.J.,Warner, N.,Maini, J.,Chan Tung, K.W.,Zakaria, H.,Pawson, T.,Donaldson, L.W.
Saccharomyces cerevisiae Ste50 binds the MAPKKK Ste11 through a head-to-tail SAM domain interaction.
J.Mol.Biol., 356:142-154, 2006

PubMed Abstract: In Saccharomyces cerevisiae, signal transduction through pathways governing mating, osmoregulation, and nitrogen starvation depends upon a direct interaction between the sterile alpha motif (SAM) domains of the Ste11 mitogen-activated protein kinase kinase kinase (MAPKKK) and its regulator Ste50. Previously, we solved the NMR structure of the SAM domain from Ste11 and identified two mutants that diminished binding to the Ste50 SAM domain. Building upon the Ste11 study, we present the NMR structure of the monomeric Ste50 SAM domain and a series of mutants bearing substitutions at surface-exposed hydrophobic amino acid residues. The mid-loop (ML) region of Ste11-SAM, defined by helices H3 and H4 and the end-helix (EH) region of Ste50-SAM, defined by helix H5, were sensitive to substitution, indicating that these two surfaces contribute to the high-affinity interaction. The combination of two mutants, Ste11-SAM-L72R and Ste50-SAM-L69R, formed a high-affinity heterodimer unencumbered by competing homotypic interactions that had prevented earlier NMR studies of the wild-type complex. Yeast bearing mutations that prevented the heterotypic Ste11-Ste50 association in vitro presented signaling defects in the mating and high-osmolarity growth pathways.

PubMed: 16337230
DOI: 10.1016/j.jmb.2005.11.012

Experimental method

SOLUTION NMR