title: Interaction of an anticancer peptide fragment of azurin with p53 and its isolated domains studied by atomic force spectroscopy.
abstract: p28 is a 28-amino acid peptide fragment of the cupredoxin azurin derived from Pseudomonas aeruginosa that preferentially penetrates cancerous cells and arrests their proliferation in vitro and in vivo. Its antitumor activity reportedly arises from post-translational stabilization of the tumor suppressor p53 normally downregulated by the binding of several ubiquitin ligases. This would require p28 to specifically bind to p53 to inhibit specific ligases from initiating proteosome-mediated degradation. In this study, atomic force spectroscopy, a nanotechnological approach, was used to investigate the interaction of p28 with full-length p53 and its isolated domains at the single molecule level. Analysis of the unbinding forces and the dissociation rate constant suggest that p28 forms a stable complex with the DNA-binding domain of p53, inhibiting the binding of ubiquitin ligases other than Mdm2 to reduce proteasomal degradation of p53.
authors.affiliation: Biophysics and Nanoscience Centre, CNISM, Facoltà di Scienze, Università della Tuscia, Viterbo, Italy. bizzarri@unitus.it
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Bizzarri
authors.forename: Simona
authors.initials: S
authors.lastname: Santini
authors.forename: Emilia
authors.initials: E
authors.lastname: Coppari
authors.forename: Monica
authors.initials: M
authors.lastname: Bucciantini
authors.forename: Silvia
authors.initials: S
authors.lastname: Di Agostino
authors.forename: Tohru
authors.initials: T
authors.lastname: Yamada
authors.forename: Craig W
authors.initials: CW
authors.lastname: Beattie
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cannistraro
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D001400:Azurin / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D018625:Microscopy, Atomic Force; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011550:Pseudomonas aeruginosa / Q000737:chemistry; D013057:Spectrum Analysis; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D055767:Immobilized Proteins; D010446:Peptide Fragments; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D001400:Azurin