ON THE TERTIARY STRUCTURE OF THE CITRUS-ICHANGENSIS SATELLITE DNA

A hexamer of the repeating unit of Citrus ichangensis satellite DNA wa s cloned. Polyacrylamide gel electrophoresis demonstrated that the sha pe of cloned hexamer is other than linear. As the computing of tertiar y coordinates made by Eckdahl and Anderson's BEN program proved, the h examer is a solenoid consisting of two turns termed coiled double heli x (CDH)-form. An electron microscopic analysis revealed small diameter circles in the hexamer under investigation. Unlike the hexamer contro l molecules are s-shaped. It is concluded that the CDH-form is a chara cteristic of the satellite DNA of Citrus ichangensis.