4Z4A

Avirulence protein 4 (Avr4) from Pseudocercospora fuligena

Summary for 4Z4A

• Entry DOI: 10.2210/pdb4z4a/pdb
• Descriptor: Carbohydrate-binding module family 14 protein, 1,2-ETHANEDIOL (3 entities in total)
• Functional Keywords: effector protein, avirulence protein, cbm-14, sugar binding protein
• Biological source: Pseudocercospora fuligena
• Total number of polymer chains: 2
• Total formula weight: 27773.01

Authors

Hurlburt, N.K.,Kohler, A.C.,Fisher, A.J. (deposition date: 2015-04-01, release date: 2016-06-29, Last modification date: 2024-11-13)

Primary citation

Kohler, A.C.,Chen, L.H.,Hurlburt, N.,Salvucci, A.,Schwessinger, B.,Fisher, A.J.,Stergiopoulos, I.
Structural Analysis of an Avr4 Effector Ortholog Offers Insight into Chitin Binding and Recognition by the Cf-4 Receptor.
Plant Cell, 28:1945-1965, 2016

PubMed Abstract: Chitin is a key component of fungal cell walls and a potent inducer of innate immune responses. Consequently, fungi may secrete chitin-binding lectins, such as the Cf-Avr4 effector protein from the tomato pathogen Cladosporium fulvum, to shield chitin from host-derived chitinases during infection. Homologs of Cf-Avr4 are found throughout Dothideomycetes, and despite their modest primary sequence identity, many are perceived by the cognate tomato immune receptor Cf-4. Here, we determined the x-ray crystal structure of Pf-Avr4 from the tomato pathogen Pseudocercospora fuligena, thus providing a three-dimensional model of an Avr4 effector protein. In addition, we explored structural, biochemical, and functional aspects of Pf-Avr4 and Cf-Avr4 to further define the biology of core effector proteins and outline a conceptual framework for their pleiotropic recognition by single immune receptors. We show that Cf-Avr4 and Pf-Avr4 share functional specificity in binding (GlcNAc)6 and in providing protection against plant- and microbial-derived chitinases, suggesting a broader role beyond deregulation of host immunity. Furthermore, structure-guided site-directed mutagenesis indicated that residues in Pf-Avr4 important for binding chitin do not directly influence recognition by Cf-4 and further suggested that the property of recognition is structurally separated or does not fully overlap with the virulence function of the effector.

PubMed: 27401545
DOI: 10.1105/tpc.15.00893

Experimental method

X-RAY DIFFRACTION (1.7 Å)