The tumor suppresser protein p53 has been called the "guardian of the genome." DNA damage induces p53 to either halt the cell cycle, allowing for repair, or initiate apoptosis. P53 is mutated in over 50% of human tumors and it has been proposed that many tumorigenic mutations are deleterious to p53
Solution structure of a peptide model of a region important for the folding of α-lactalbumin provides evidence for the formation of nonnative structure in the denatured state
✍ Scribed by Stephen J. Demarest; Daniel P. Raleigh
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 373 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0887-3585
No coin nor oath required. For personal study only.
✦ Synopsis
Elucidating the properties of the denatured state of proteins under conditions relevant for their folding is a key factor in understanding the folding process. We show that a peptide corresponding to residues 111-120 of human ␣-lactalbumin has a pronounced propensity to adopt nonnative structure in aqueous solution. Two-dimensional NMR provides evidence for a structured, nonnative conformation in fast exchange with a random coil ensemble. A total of 78 Rotating Frame Overhauser Effects (ROEs) were used to calculate the conformation of the structured population. A nonnative cluster of hydrophobic residues involving the side chains of K114, W118, L119, and A120 is observed, which helps to stabilize a turnlike conformation in the vicinity of residues 115-118. The structure in 30% (vol/vol) TFE was also calculated. Interestingly, the addition of TFE did not simply amplify the population of the structured conformer observed in H 2 O, but instead induced a new conformation. The implications for the folding of the intact protein are discussed. We also discuss the implications of this study for the relevance of the use of mixed TFE/H 2 O solvent systems to study isolated peptides.
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