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Updated: Aug 9, 2026

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Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides
Published on: June 19, 2012
Human full-length Securin is a natively unfolded protein
Nuria Sánchez-Puig1, Dmitry B Veprintsev, Alan R Fersht
1Centre for Protein Engineering, Medical Research Council, Hills Road CB2 2QH, Cambridge, UK.
Summary
Human Securin (PTTG1) is a natively unfolded protein lacking stable structure. Biophysical studies found no direct interaction between Securin and the p53 tumor suppressor protein in vitro.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Human Securin, also known as pituitary tumor transforming gene 1 (PTTG1) product, is an estrogen-regulated proto-oncogene.
- Securin possesses multifunctional properties relevant to cell growth and transformation.
Purpose of the Study:
- To characterize the structural properties of human full-length Securin.
- To investigate the potential direct interaction between Securin and the p53 tumor suppressor protein.
Main Methods:
- Biophysical techniques including nuclear magnetic resonance (NMR), circular dichroism (CD), and size-exclusion chromatography (SEC).
- Analytical ultracentrifugation (AUC) and fluorescence anisotropy assays were employed to study protein interactions.
Main Results:
- Securin exhibited a lack of defined tertiary and secondary structure under physiological conditions, behaving as an extended polypeptide.
- These findings classify Securin as a natively unfolded protein.
- AUC and fluorescence anisotropy studies showed no evidence of direct binding between Securin and p53 in vitro.
Conclusions:
- Human Securin is an intrinsically disordered protein.
- Securin does not directly interact with p53, suggesting indirect mechanisms for any functional interplay.
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