title: Characterization of linear forms of the circular enterocin AS-48 obtained by limited proteolysis.
abstract: AS-48 is a 70-residue circular peptide from Enterococcus faecalis with a broad antibacterial activity. Here, we produced by limited proteolysis a protein species carrying a single nicking and fragments of 55 and 38 residues. Nicked AS-48 showed a lower helicity by far-ultraviolet circular dichroism and a reduced stability to thermal denaturation, but it was active against the sensitive bacteria assayed. The fragments also partly retained the biological activity of the intact protein. These results indicate that circularization is not required for the bactericidal activity, but it is important to stabilize the native structure. Moreover, it is possible to reduce the sequence to a minimal AS-48 domain without causing inactivation of this bacteriocin.
authors.affiliation: Department of Microbiology, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Montalbán-López
authors.forename: Barbara
authors.initials: B
authors.lastname: Spolaore
authors.forename: Odra
authors.initials: O
authors.lastname: Pinato
authors.forename: Manuel
authors.initials: M
authors.lastname: Martínez-Bueno
authors.forename: Eva
authors.initials: E
authors.lastname: Valdivia
authors.forename: Mercedes
authors.initials: M
authors.lastname: Maqueda
authors.forename: Angelo
authors.initials: A
authors.lastname: Fontana