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Conservation of helical bundle structure between the exocyst subunits
Nicole J Croteau1, Melonnie L M Furgason, Damien Devos
1Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.
Plos One
|February 14, 2009
Summary
Advanced computational methods reveal that all eight exocyst subunits share similar helical bundle structures. This finding enabled the creation of a soluble Sec10p protein domain for further study.
Area of Science:
- Cell biology
- Structural biology
- Protein complex research
Background:
- The exocyst is a vital hetero-octomeric complex regulating vesicle transport in eukaryotic cells.
- Despite low sequence identity (<10%) among subunits, some share a helical bundle topology.
- Many exocyst subunits are difficult to study due to insolubility.
Purpose of the Study:
- To computationally predict and experimentally validate the structural similarity of all exocyst subunits.
- To identify soluble domains of previously intractable exocyst subunits for biochemical and structural analysis.
Main Methods:
- Utilized advanced hidden Markov models (HMMs) and secondary structure predictions.
- Identified and purified a predicted soluble domain of the yeast Sec10p subunit.
- Characterized the biophysical properties of the purified Sec10p domain.
Main Results:
- Detected significant sequence similarity across all exocyst subunits, predicting shared helical bundle structures.
- Successfully produced a soluble, folded domain of the yeast Sec10p subunit.
- Confirmed the purified Sec10p domain exhibits ~60% alpha-helicity and interacts with binding partners.
Conclusions:
- Validated the hypothesis that all eight exocyst subunits possess similar helical bundle structures using HMM predictions.
- Demonstrated the utility of computational predictions in identifying soluble protein domains.
- Successfully created and characterized a soluble Sec10p domain, facilitating future exocyst research.
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