The Structure of the Elicitor Cerato-platanin (CP), the First Member of the CP Fungal Protein Family, Reveals a Double {psi}{beta}-Barrel Fold and Carbohydrate Binding

DE OLIVEIRA A.L.*; GALLO M.*; PAZZAGLI L.; BENEDETTI C.E.; CAPPUGI G.; SCALA A.; PANTERA B.; SPISNI A.; PERTINHEZ T.A.; CICERO D.O.

JOURNAL OF BIOLOGICAL CHEMISTRY

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Año: 2011 vol. 286 p. 17560 - 17568

0021-9258

Cerato-platanin (CP) is a secretion proteinproduced by the fungal pathogen Ceratocystisplatani, the causal agent of the plane cankerdisease and the founder of the CP family. CPis considered a pathogen-associated molecularpattern (PAMP) since it induces variousdefence responses in the host, includingproduction of phytoalexins and cell death.Although much is known about the propertiesof CP and related proteins as elicitors of plantdefence mechanisms, its biochemical activityand host target(s) remain elusive. Here, wepresent the 3D structure of CP. The protein,that exhibits a remarkable pH and thermalstability, has a double-yb-barrel fold quitesimilar to those found in expansins,endoglucanases and in the plant defencebarwin. Interestingly, although CP lacks lyticactivity against a variety of carbohydrates, itbinds oligosaccharides. We identified the CPregion responsible for that binding as ashallow surface located at one side of the b-barrel. Chemical shift perturbation of theprotein amide protons, induced by oligo-Nacetylglucosaminesof various size, shows thatall the residues involved in oligosaccharidebinding are conserved among the members ofthe CP family. Overall, the results suggestthat CP might be involved in polysacchariderecognition and that the double-yb-barrelfold is widespread in distantly relatedorganisms where it is often involved in hostmicrobe interactions.