title: A single amino-acid substitution allows endo-polygalacturonase of Fusarium verticillioides to acquire recognition by PGIP2 from Phaseolus vulgaris.
abstract: Polygalacturonases (PGs) are secreted by phytopathogenic fungi to degrade the plant cell wall homogalacturonan during plant infection. To counteract Pgs, plants have evolved polygalacturonase-inhibiting proteins (PGIPs) that slow down fungal infection and defend cell wall integrity. PGIPs favour the accumulation of oligogalacturonides, which are homogalacturonan fragments that act as endogenous elicitors of plant defence responses. We have previously shown that PGIP2 from Phaseolus vulgaris (PvPGIP2) forms a complex with PG from Fusarium phyllophilum (FpPG), hindering the enzyme active site cleft from substrate. Here we analyse by small angle X-ray scattering (SAXS) the interaction between PvPGIP2 and a PG from Colletotrichum lupini (CluPG1). We show a different shape of the PG-PGIP complex, which allows substrate entry and provides a structural explanation for the different inhibition kinetics exhibited by PvPGIP2 towards the two isoenzymes. The analysis of SAXS structures allowed us to investigate the basis of the inability of PG from Fusarium verticilloides (FvPG) to be inhibited by PvPGIP2 or by any other known PGIP. FvPG is 92.5% identical to FpPG, and we show here, by both loss- and gain-of-function mutations, that a single amino acid site acts as a switch for FvPG recognition by PvPGIP2.
authors.affiliation: Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, Roma, Italy.
authors.forename: Manuel
authors.initials: M
authors.lastname: Benedetti
authors.forename: Federico
authors.initials: F
authors.lastname: Andreani
authors.forename: Claudia
authors.initials: C
authors.lastname: Leggio
authors.forename: Luciano
authors.initials: L
authors.lastname: Galantini
authors.forename: Adele
authors.initials: A
authors.lastname: Di Matteo
authors.forename: Nicolae Viorel
authors.initials: NV
authors.lastname: Pavel
authors.forename: Giulia
authors.initials: G
authors.lastname: De Lorenzo
authors.forename: Felice
authors.initials: F
authors.lastname: Cervone
authors.forename: Luca
authors.initials: L
authors.lastname: Federici
authors.forename: Francesca
authors.initials: F
authors.lastname: Sicilia
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics*; D005670:Fusarium / Q000235:genetics* / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D027805:Phaseolus / Q000378:metabolism* / Q000382:microbiology*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011096:Polygalacturonase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D016415:Sequence Alignment
chemical_list: C081479:PGIP protein, plant; D010940:Plant Proteins; D011096:Polygalacturonase