Adsorption protein of bacteriophage fl: solubilization in deoxycholate and localization in the fl virion

Abstract

A complex containing the minor coat protein or adsorption protein (A protein) of bacteriophage f1 was solubilized from the f1 virion, using the detergent deoxycholate. This complex was resolved from the f1 DNA and from the f1 major coat protein, or B protein, by gel filtration in the presence of deoxycholate. The A protein complex migrated as a single band on sodium dodecyl sulfate-urea-polyacrylamide gels corresponding to a MW of 60,000. Analysis of the amino acid composition and amino terminal residues of this preparation indicates that the preparation contains a 20% contamination of additional protein species. Antibody against purified [phage] fd A protein is cross-reactive with deoxycholate-purified f1 A protein and with f1 phage. EM observation of negatively stained complexes of f1 phage with this anti-fd A protein antibody and ferritin conjugated goat anti-rabbit Ig[immunoglobulin]G antibody revealed phages with ferritin particles at their termini or complexes of 2 or more phages joined together at 1 end by ferritin, indicating that the complex of A protein molecules is located at 1 end of the filamentous f1 virion.