Hot-spot mutants of p53 core domain evince characteristic local structural changes

Abstract

Most of the oncogenic mutations in the tumor suppressor p53 map to its DNA-binding (core) domain. It is thus a potential target in cancer therapy for rescue by drugs. To begin to understand how mutation inactivates p53 and hence to provide a structural basis for drug design, we have compared structures of wild-type and mutant p53 core domains in solution by NMR spectroscopy. Structural changes introduced by five hot-spot mutations (V143A, G245S, R248Q, R249S, and R273H) were monitored by chemical-shift changes. Only localized changes are observed for G245S, R248Q, R249S, and R273H, suggesting that the overall tertiary folds of these mutant proteins are similar to that of wild type. Structural changes in R273H are found mainly in the loop-sheet-helix motif and the loop L3 of the core domain. Mutations in L3 (G245S, R248Q, and R249S) introduce structural changes in the loop L2 and L3 as well as terminal residues of strands 4, 9, and 10. It is noteworthy that R248Q, which is often regarded as a contact mutant that affects only interactions with DNA, introduces structural changes as extensive as the other loop L3 mutations (G245S and R249S). These changes suggest that R248Q is also a structural mutant that perturbs the structure of loop L2-L3 regions of the p53 core domain. In contrast to other mutants, replacement of the core residue valine 143 to alanine causes chemical-shift changes in almost all residues in the ␤-sandwich and the DNA-binding surface. Long-range effects of V143A mutation may affect the specificity of DNA binding.

Mutant p53 drives multinucleation and invasion through a process that is suppressed by ANKRD11

“…In contrast to other structural mutants, G245S did not interact with p63 or p73 (Figure 7). However, the p53-G245S protein is only locally distorted in comparison with p53-R175H and p53-R282W, which are distorted globally (Wong et al, 1999;Brosh and Rotter, 2009). These findings suggest that the extent of mutant p53 protein distortion may also dictate its ability to sequester p63 and p73.…”

Transcriptional regulation by p53: one protein, many possibilities

“…R175, G245, R249, R282) diminish binding by destabilizing the tertiary structure of p53 DBD. 27,28 Mutation at position 248 (R248), in addition to breaking DNA-protein contacts, also introduces extensive structural changes into the DBD. 27 Among these mutations are also those that lead to the loss or significant decrease in Zn 2 þ ions, normally chelated by C176 and H179 of the L2 loop and by C238 and C242 of the L3 loop.…”

Reactivation of mutant p53: molecular mechanisms and therapeutic potential

“…Structural consequences of oncogenic mutations in the p53 DNA-binding domain The cocrystal structure of the wild-type p53 core domain bound to DNA together with more recent nuclear magnetic resonance (NMR) and X-ray studies on tumor-derived core domain mutants have revealed the structural impact of amino-acid residues that are most frequently mutated in human cancers (Cho et al, 1994;Wong et al, 1999;Joerger et al, 2004Joerger et al, , 2005aAng et al, 2006). The so-called DNA contact mutants, for example R273H and R248Q, carry substitutions of residues that directly contact DNA.…”