Molecular Shape of α-Connectin, an Elastic Filamentous Protein of Skeletal Muscle

Abstract

Rotary shadowed image of α-connectin (titin 1; TI), mother molecule of the muscle elastic filament, was a long thin rod, approximately 1μm long and 3-4nm wide, with a globular head at one end. β-Connectin (titin 2; TII), the proteolytic product of α-connectin, was also a long rod, about 0.85μm long and 3-4nm wide without the head. It appeared that both α-and β-connectin rods consisted of two laterally associated stands, approximately 1.5nm wide.