Carrascosa J L, Kellenberger E
J Virol. 1978 Mar;25(3):831-44. doi: 10.1128/JVI.25.3.831-844.1978.
We have isolated and characterized two types of particles produced in comparable amounts by mutants in gene 17: the empty large particle and the empty small particle. Dimensions, morphology, stability, and protein composition of the empty large particle are very similar to those of the capsids or empty heads of mature phage. The other type of particle (empty small particle) is very similar in dimensions and stability to the prehead, but differs in that it is composed of processed proteins (gp23, gp24, IpIII). Structural analysis has shown that the protein subunits of the empty small particles are arranged in an unexpanded type of lattice (11.2 to 11.3 nm), whereas the empty large particles have an expanded lattice (13 nm). The characterization of the empty small particle as being composed of cleaved proteins, but still unexpanded, shows that the expansion of the T4 head shell is not necessarily linked to the cleavage of the structural proteins.
我们已经分离并鉴定了由基因17中的突变体产生的两种数量相当的颗粒：空的大颗粒和空的小颗粒。空的大颗粒的尺寸、形态、稳定性和蛋白质组成与成熟噬菌体的衣壳或空头部非常相似。另一种颗粒（空的小颗粒）在尺寸和稳定性上与前头部非常相似，但不同之处在于它由经过加工的蛋白质（gp23、gp24、IpIII）组成。结构分析表明，空的小颗粒的蛋白质亚基以未扩展的晶格类型（11.2至11.3纳米）排列，而空的大颗粒具有扩展的晶格（13纳米）。将空的小颗粒表征为由裂解蛋白组成但仍未扩展，这表明T4头部外壳的扩展不一定与结构蛋白的裂解相关。
