Properties of the histidines of chymotrypsinogen: comparison with alpha-chymotrypsin

Adeno-associated virus linear, single polynucleotide chains contain an inverted terminal repetition which allows the formation of single-stranded circles when the DNA is exposed to annealing conditions. Under appropriate annealing conditions single-stranded circular dimers are formed, the majority of which have two projections separated by 180 ° visible in the electron microscope. We conclude that these projections represent the regions of self-complementarity (inverted terminal repetition) contained within the virus DNA. Measurements of the lengths of the projections indicate that the length of the inverted terminal repetition represents approximately 1.5% of the genome.