Computational Survey of FHIT, A Putative Human Tumor Suppressor, Truncates Structure

Fragile Histidine Triad protein (FHIT), as a known tumor suppressor protein, has been proposed to play crucial role in inhibiting p53 degradation by MDM2. Studies have confirmed FHIT interaction with p53 or MDM2, although functional interacting domains of FHIT with MDM2 and/or p53 are not completely defined. Thus, through determining the significant structural interacting domains of FHIT, information with regard to MDM2 and p53 would be provided. As there were no previous studies evaluating the interaction of optimized important parts of target molecules, docking study was employed. Truncated structures of FHIT were screened to reveal critical sections engaging in FHIT interaction. HEX program was used in order to study the interaction of target structures. Given the total energy, FHIT structures (β5-7, α1) and (α1) of FHIT were showed to be better candidates in comparison with other structures in interaction with optimized MDM2 part. Furthermore, FHIT structures (β4-7, α1) and (β5-7, α1) were considered to be better than other structures in interaction with optimized p53 part. FHIT truncates which interact with MDM2 optimized part exhibited lower energy levels than FHIT truncates which interact with p53 optimized part. Our results can be useful for designing new inhibitors of this protein complex interaction which would result in tumor repression.