Visualization of beta-sheets and side-chain clusters in two-dimensional periodic arrays of streptavidin on phospholipid monolayers by electron crystallography

• Published in: Biophysical journal 1996, Vol.70 (1), p.57-68
• Main Authors: Avila-Sakar, A.J., Chiu, W.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Biophysical Phenomena; Biophysics; Crystallography - methods; Crystallography, X-Ray; Electrons; Models, Molecular; Molecular Sequence Data; Molecular Structure; Phospholipids; Protein Conformation; Protein Structure, Secondary; Streptavidin
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/S0006-3495(96)79597-8

The biotin-binding protein streptavidin was crystallized as two-dimensional periodic arrays on biotinylated phospholipid monolayers. Electron diffraction patterns and images of the arrays embedded in vitreous ice were recorded to near-atomic resolution. Amplitudes and phases of structure factors were computed and combined to produce a 3 A projection density map. The reliability of the map was verified by comparing it to the available x-ray atomic model of the molecule. Projection densities from beta-strands and some amino acid side chains were identified from the electron cryomicroscopy map. These results demonstrate the first near-atomic image of this type of protein periodic array by electron crystallography, which has a great potential to aid in the structural characterization of molecular arrays engineered on a monolayer for various basic or biotechnological applications.