Phytophthora and Pythium species are among the most aggressive plant pathogens, as they invade many economically important crops and forest trees. They secrete large amounts
of 10 kDa proteins called elicitins that can act as elicitors of plant defence mechanisms. These proteins may also induce a
hypersensitive response (HR) including plant cell necrosis, with different levels of toxicity depending on their pI. Recent
studies showed that elicitins function as sterol carrier proteins.
The crystallographic structure of the highly necrotic recombinant -cinnamomin ( -CIN) from Phytophthora cinnamomi has been determined at 1.8 A Ê resolution using the molecularreplacement method. -CIN has the same overall structure as -cryptogein ( -CRY), an elicitin secreted by Phytophthora
cryptogea, although it shows a different surface electrostatic potential distribution. The protein was expressed in Pichia pastoris and crystallized in the triclinic space group with two monomers in the asymmetric unit. The interface formed by
these two monomers resembles that from -CRY dimer, although with fewer interactions
