Harpins are proteins able to elicit hypersensitive response (HR) in non-host plants and are required for pathogenicity in host plants. HrpZ forms ion-conducting pores permeable for cations. Such pore-forming activity may allow nutrient release and/or delivery of virulence factors during bacterial colonization of host plants. Also binds peptides, which contain tryptophan and leucine, suggesting a protein-protein interaction between the harpin and a host plant protein, possibly involved in the bacterial pathogenesis. Homomultimeric. Secreted via type III secretion system (TTSS), delivered into the host intercellular space. HrpZ travels through the hrp pilus and it is secreted only from the pilus tip (By similarity). It is found to associate stably with liposomes and synthetic bilayer membranes. Expression enhanced by contact with host cell wall. Also regulated by HrpRS and HrpL. The glycine-rich region is characteristic of harpins. Belongs to the harpin HrpZ family.