Homology between the seed cytolysin enterolobin and bacterial aerolysins

Abstract

Enterolobin, a 55-kDa cytolytic, inflammatory, and insecticidal protein isolated from seeds of the Brazilian tree Enterolobium contortisiliquum (Leguminosae-Mimosoideae) has been further purified and partially sequenced by using both manual and automated methods. A computational search of enterolobin partial amino acid sequence against the PIR database revealed possible sequence similarities with aerolysins, cytolytic proteins from Aeromonas species. An alignment of enterolobin partial sequence to the amino acid sequences of A. hydrophila and A. sobria aerolysins showed several similar regions with many residue identities. The seed protein enterolobin and the bacterial aerolysins may be homologous proteins despite the distant phylogenetic relationship.

Inhibition of Oligomerization of Aerolysin from Aeromonas Hydrophila: Homology Modeling and Docking Approach for Exploration of Hemorrhagic Septicemia

“…The various steps that allow aerolysin to form a pore in the plasma membrane of a target eukaryotic cell have now been identified; secretion, activation, receptor binding, heptamerization and membrane insertion but the mechanism are not fully understood. Homology searches with other proteins in the database reveal two other protein alpha-toxins from C. septicum [39] and a plant enterolobin [40]. The crystal structure of proaerolysin reveals an L-shaped molecule which can be divided into a small N-terminal globular domain (Domain I) and a long elongated domain.…”

Fungal hemolysins

“…Current knowledge suggests that hemolysins are pore-forming toxins that interact with specific ligands on the surface of various target cells [1]. Although extensively studied in various bacterial species [1,2], hemolysins have also been reported in fungi [3,4], plants [5], invertebrates [6– 8], and mammals (perforins) [9]. Bacterial hemolysins have been well characterized due to the role of these proteins in pathogenesis and, their structural details, mechanisms of hemolysis, ligand differences on target cells, and diagnostic potential have been described [2,10– 19].…”

Extending the Aerolysin Family: From Bacteria to Vertebrates

“…Aerolysin is produced by Aeromonas species, but related proteins are present in both Gram-positive and Gram-negative bacteria, plants and eukaryotes. It shares high sequence identity with alpha-toxin from Clostridium septicum [4], as well as with enterolobin produced by the seeds of the Brazilian tree Enterolobium contorliquum [5], [6]. The aerolysin family was subsequently extended, based on the analysis of conserved motifs [7], to hydralysins produced by Cnidaria , ε-toxin form Clostridium perfringens [8], a hemolytic lectin from the parasitic mushroom Laetiporus sulphureus [9] and structurally to parasporin-2 from Bacillus thuringiensis [10].…”