Fig. 4: Conformational changes in the sheath protein.
From: High-resolution cryo-EM structure of the Pseudomonas bacteriophage E217
a Magnified view of the intermolecular β-sheet formed by three sheath proteins, referred to as subunits A, B, and C. On the left side is the association in the extended tail before contraction, while on the right panel is the same secondary structure element after tail contraction. In both panels, subunit A exposes the β-turn spanning residues 460–488 (e.g., β-strands #1 and #2, colored in pink) that hydrogen bond with subunit B C-terminal β-strand #3 (green) and subunit C N-terminal β-strand #4 (yellow). b Quaternary structure representation of the three sheath subunits A, B, and C described in (a). c A section view of the E217 sheath in the extended versus contracted states.
