title: Mutants of the tumour suppressor p53 L1 loop as second-site suppressors for restoring DNA binding to oncogenic p53 mutations: structural and biochemical insights.
abstract: To assess the potential of mutations from the L1 loop of the tumour suppressor p53 as second-site suppressors, the effect of H115N and S116M on the p53 'hot spot' mutations has been investigated using the double-mutant approach. The effects of these two mutants on the p53 hot spots in terms of thermal stability and DNA binding were evaluated. The results show that: (i) the p53 mutants H115N and S116M are thermally more stable than wild-type p53; (ii) H115N but not S116M is capable of rescuing the DNA binding of one of the most frequent p53 mutants in cancer, R248Q, as shown by binding of R248Q/H115N to gadd45 (the promoter of a gene involved in cell-cycle arrest); (iii) the double mutant R248Q/H115N is more stable than wild-type p53; (iv) the effect of H115N as a second-site suppressor to restore DNA-binding activity is specific to R248Q, but not to R248W; (v) molecular-dynamics simulations indicate that R248Q/H115N has a conformation similar to wild-type p53, which is distinct from that of R248Q. These findings could be exploited in designing strategies for cancer therapy to identify molecules that could mimic the effect of H115N in restoring function to oncogenic p53 mutants.
authors.affiliation: Department of Biochemistry, King's College London, UK.
authors.forename: Assia
authors.initials: A
authors.lastname: Merabet
authors.forename: Hellen
authors.initials: H
authors.lastname: Houlleberghs
authors.forename: Kate
authors.initials: K
authors.lastname: Maclagan
authors.forename: Ester
authors.initials: E
authors.lastname: Akanho
authors.forename: Tam T T
authors.initials: TT
authors.lastname: Bui
authors.forename: Bruno
authors.initials: B
authors.lastname: Pagano
authors.forename: Alex F
authors.initials: AF
authors.lastname: Drake
authors.forename: Franca
authors.initials: F
authors.lastname: Fraternali
authors.forename: Penka V
authors.initials: PV
authors.lastname: Nikolova
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D006801:Humans; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense / Q000502:physiology*; D009369:Neoplasms / Q000628:therapy; D009687:Nuclear Proteins / Q000378:metabolism; D015513:Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D011487:Protein Conformation; D055550:Protein Stability; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D000097642:GADD45 Proteins
chemical_list: D018797:Cell Cycle Proteins; D004247:DNA; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C439070:GADD45A protein, human; D000097642:GADD45 Proteins