THE PROTEIN CRYSTALS OFBACILLUS THURINGIENSISBERLINER

Publisher Website
Google Scholar
Abstract
On sporulation the cells of the insect pathogen Bacillus thuringiensis contain at one end a spore and at the other end a diamond shaped crystal. A method has been developed for the separation of the alkali dispersible crystal material from spores, vegetative cell debris, and their alkali soluble components. Two methods are given for the preparation of suspensions of intact crystals free from other material. One method depends on the mechanical disruption of the spores, the other on germination and autolysis of the spore contents. After either method clean suspensions of crystals were obtained by washing and differential centrifugation. The purest preparations have yielded a substance precipitable with trichloracetic acid, possessing the ultraviolet absorption characteristics of protein, containing over 17% nitrogen and at least 17 amino acids, but no phosphorus. Examination of the crystals with the electron microscope has shown that they have a tetragonal form and possess some fine structures; no virus particles were found in alkali dispersed crystal protein.