Structural Characteristics of the Short-Tail Fibers of T4 Bacteriophage

✍ Scribed by Jorge Zorzopulos; Sara DeLong; Virginia Chapman; Lloyd M. Kozloff

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 834 KB
• Volume: 18
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.1982.240180309

✦ Synopsis

Abstract

The characteristics of pure preparations of short‐tail fibers of bacteriophage T4 have been studied in the optical and electron microscope. Three main structures were observed: 1) spheres of 8.1 nm diameter; 2) fibers 43 nm long and 3.8 nm thick; and 3) fibers 54 nm long and 3.2 nm thick. Both types of fibers exhibited a regular beaded appearance. The 43‐nm fibers were the most abundant structure. During the process of purification of the short‐tail fibers, the formation of aggregates was observed each time the material containing the short‐tail fibers was dialyzed against saline solutions. These aggregates became increasingly fibrous (as observed in the optical microscope) as the material used was increasingly enriched in short‐tail fibers. Finally, most of the aggregates were of the fibrous type when they were formed from a purified preparation of short‐tail fibers. In the electron microscope, it was found that the filamentous aggregates were organized in well‐defined bundles. The amino acid composition of the highly purified short‐tail fibers was also determined. Among the known fibrous proteins, the ones that most resemble the amino acid composition of the short‐tail fibers are actin and fibrinogen. These observations are discussed in relation to the T4 short‐tail fiber structure and their localization on the hexagonal baseplate of the T4 tail structure.