FIBRILLAR PROTEINS OF BACTERIOPHAGE-T4 AS A FOLDING MODEL

Many hereditary human diseases are often connected with aberrant prote in folding. Understanding of intracellular folding mechanisms ij also important for biotechnology and protein engineering in the de novo des ign of molecules with predefined properties. The basic information on folding and its intermediates was obtained upon investigation of singl e-domain globular proteins. At the same time, mechanisms of folding of such fibrillar proteins as myosin, keratins, and cell filaments have not been studied. The review briefly summarizes the results obtained i n the Laboratory of Molecular Genetics on the in vivo structure and fo lding of two fibrillar oligomeric proteins of bacteriophage T4, fibrit in and adhesin. X-ray analysis of fibritin has shown that its identica l subunits associate in a trimer, thus forming a parallel coiled coil. The carboxyl domain of the molecule, or ''foldon'' according to our t erminology, is formed by two short antiparallel beta-strands packed in the trimer as a stable structure of the beta-propeller type. The fold on initiates fibritin trimerization and coiled coil formation. We are finishing our study oi the detailed organization of adhesin and the ro le of a chaperon encoded by the phage gene 57 in its folding.