4BJM

Crystal structure of the flax-rust effector avrM

Summary for 4BJM

• Entry DOI: 10.2210/pdb4bjm/pdb
• Related: 4BJN
• Descriptor: AVRM, CHLORIDE ION (3 entities in total)
• Functional Keywords: plant diseases, immunity, innate, protein multimerization, protein binding, protein transport, membrane translocation, structure-activity relationship virulence factors
• Biological source: MELAMPSORA LINI (FLAX RUST)
• Total number of polymer chains: 4
• Total formula weight: 109699.59

Authors

Ve, T.,Williams, S.J.,Kobe, B. (deposition date: 2013-04-19, release date: 2013-10-16, Last modification date: 2024-05-08)

Primary citation

Ve, T.,Williams, S.J.,Catanzariti, A.M.,Rafiqi, M.,Rahman, M.,Ellis, J.G.,Hardham, A.R.,Jones, D.A.,Anderson, P.A.,Dodds, P.N.,Kobe, B.
Structures of the Flax-Rust Effector Avrm Reveal Insights Into the Molecular Basis of Plant-Cell Entry and Effector-Triggered Immunity
Proc.Natl.Acad.Sci.USA, 110:17594-, 2013

PubMed Abstract: Fungal and oomycete pathogens cause some of the most devastating diseases in crop plants, and facilitate infection by delivering a large number of effector molecules into the plant cell. AvrM is a secreted effector protein from flax rust (Melampsora lini) that can internalize into plant cells in the absence of the pathogen, binds to phosphoinositides (PIPs), and is recognized directly by the resistance protein M in flax (Linum usitatissimum), resulting in effector-triggered immunity. We determined the crystal structures of two naturally occurring variants of AvrM, AvrM-A and avrM, and both reveal an L-shaped fold consisting of a tandem duplicated four-helix motif, which displays similarity to the WY domain core in oomycete effectors. In the crystals, both AvrM variants form a dimer with an unusual nonglobular shape. Our functional analysis of AvrM reveals that a hydrophobic surface patch conserved between both variants is required for internalization into plant cells, whereas the C-terminal coiled-coil domain mediates interaction with M. AvrM binding to PIPs is dependent on positive surface charges, and mutations that abrogate PIP binding have no significant effect on internalization, suggesting that AvrM binding to PIPs is not essential for transport of AvrM across the plant membrane. The structure of AvrM and the identification of functionally important surface regions advance our understanding of the molecular mechanisms underlying how effectors enter plant cells and how they are detected by the plant immune system.

PubMed: 24101475
DOI: 10.1073/PNAS.1307614110

Experimental method

X-RAY DIFFRACTION (2.6 Å)