In silico study of fragile histidine triad interaction domains with MDM2 and p53

BACKGROUND Fragile histidine triad (FHIT) is considered as a member of the histidine triad (HIT) nucleotide-binding protein superfamily regarded as a putative tumor suppressor executing crucial role in inhibiting p53 degradation by MDM2. Accumulating evidences indicate FHIT interaction with p53 or MDM2; however, there is no certain study deciphering functional domains of FHIT involving in the interaction with MDM2 and/or p53. In this regard, such evident interaction can spring in mind determining important domains of FHIT binding to MDM2 with regard to p53. MATERIALS AND METHODS Since there were not any previous studies appraising complete three-dimensional structures of target molecules, molecular modeling was carried out to construct three-dimensional models of full FHIT, MDM2, P53 and also FHIT segments. Truncated structures of FHIT were created to reveal critical regions engaging in FHIT interaction. RESULTS Given the shape and shape/electrostatic total energy, FHIT structures (β1-5), (β3-7, α1), and (β5-7, α1) appeared to be better candidates than other structures in interaction with full MDM2. Furthermore, FHIT structures (β6-7), (β6-7, α1), (β4-7, α1) were considered to be better than other structures in interaction with p53. FHIT truncates that interact with MDM2 presented lower energy levels than FHIT truncates interacting with p53. CONCLUSION These findings are beneficial to understand the mechanism of the FHIT-MDM2-p53 complex activation for designing inhibitory compounds.