Hydrophobic side-chain size is a determinant of the three-dimensional structure of the p53 oligomerization domain.
McCoy, M., Stavridi, E.S., Waterman, J.L., Wieczorek, A.M., Opella, S.J., Halazonetis, T.D.(1997) EMBO J 16: 6230-6236
- PubMed: 9321402 
- DOI: https://doi.org/10.1093/emboj/16.20.6230
- Primary Citation of Related Structures:  
1A1U - PubMed Abstract: 
The p53 tumor suppressor oligomerization domain, a dimer of two primary dimers, is an independently folding domain whose subunits consist of a beta-strand, a tight turn and an alpha-helix. To evaluate the effect of hydrophobic side-chains on three-dimensional structure, we substituted residues Phe341 and Leu344 in the alpha-helix with other hydrophobic amino acids. Substitutions that resulted in residue 341 having a smaller side-chain than residue 344 switched the stoichiometry of the domain from tetrameric to dimeric. The three-dimensional structure of one such dimer was determined by multidimensional NMR spectroscopy. When compared with the primary dimer of the wild-type p53 oligomerization domain, the mutant dimer showed a switch in alpha-helical packing from anti-parallel to parallel and rotation of the alpha-helices relative to the beta-strands. Hydrophobic side-chain size is therefore an important determinant of a protein fold.
Organizational Affiliation: 
Departments of Molecular Genetics and Structural Biology, The Wistar Institute, Philadelphia, PA 19104-4268, USA.