A proposed structure of the prolate phage T4 prehead core. An electron microscopic study.

摘要: The major core protein of T4 preheads, gp22, self-assembles into filaments that are about 9.5 nm wide, 2 to 3 thick, and have an undefined length. mass such ribbons, determined by electron scattering in the STEM, is 19 300 daltons/nm, indicating one gp22 molecule (Mr = 27 000) per 1.4 nm. surface vitro assembled, freeze-dried prehead cores shows 9-nm-spaced modulations, running at angle 35° equator structure. This result, combined with fact abnormally elongated preheads can be described as a six-start helix ( Paulson Laemmli, 1977 ), suggests formed six arranged distorted helical way. At or both ends, apparently attached special structure, possibly containing gp20. On this basis simple mechanism for determination size prolate shape head discussed.