Infrared spectroscopic study of the pH-dependent secondary structure of brain clathrin

• Published in: Biochemistry (Easton) Vol. 23; no. 4; pp. 625 - 631
• Main Authors: Vincent, James S, Steer, Clifford J, Levin, Ira W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.1984
• Subjects: Biological and medical sciences; brain; clathrin; Fundamental and applied biological sciences. Psychology; I.R. spectroscopy; Molecular biophysics; secondary structure; Structure in molecular biology; Tridimensional structure; Proteins; Infrared spectrometry; Vertebrata; Mammalia; PH; Brain (Vertebrata); Artiodactyla; Beef; Secondary structure; Ungulata
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00299a006

The lattice material surrounding brain coated vesicles is formed predominately from a M sub(r) 180,000 polypeptide subunit structure termed clathrin. The vesicle coat is dissociated from the bilayer membrane by mild alkaline solutions (pH 8.5) to form clathrin trimers, or triskelions. In solution, at pH 6.5, the triskelions assemble into cagelike structures exhibiting lattices whose hexagonal and pentagonal polyhedral faces are similar to those associated with the coated vesicles. The secondary structures of these clathrin species in aqueous media were characterized through an examination of the infrared spectroscopic amide I and II vibrational frequency regions in an effort to monitor the structural changes that arise as the water-soluble triskelions assemble into cagelike networks. The spectral results suggest that for structural studies involving protein-protein and protein-lipid interactions, the reconstituted, water-soluble cages provide faithful model systems for the clathrin coat associated with intact membranes.