Structural states of dictyostelium myosin

✍ Scribed by Stewart, Peter R. ;Spudich, James A.

• Book ID: 102927801
• Publisher: Wiley (John Wiley & Sons)
• Year: 1979
• Tongue: English
• Weight: 983 KB
• Volume: 12
• Category: Article
• ISSN: 0091-7419
• DOI: 10.1002/jss.400120102

✦ Synopsis

Myosin purified from Dictyostelium amoebae has approximately 10% by weight of RNA associated with it, unless specific steps (DEAE cellulose chromatography or RNase digestion) are taken t o remove it. This RNA has significant effects on the structural states formed by the myosin at low ionic strength in the presence of Mg2+. filaments (540 nm long, 33 nm thick), often with a bare zone and a 15-nm transverse repeat. Rapid precipitation of myosin with copurified RNA yields linear aggregates of bipolar filaments, showing some lateral association.

Slow precipitation of RNA-free myosin by dialysis yields very long filaments or ribbons (>5 ym, 30-60 nm wide) in which the myosin may be packed diagonally across the filament, similar t o the "side-polar" aggregates formed by other nonmuscle myosins and by smooth muscle myosin (Craig R, Megerman J :