9XQS

Structure of the inner peripheral region in the phage phiKZ baseplate complex

Summary for 9XQS

• Entry DOI: 10.2210/pdb9xqs/pdb
• EMDB information: 67121
• Descriptor: PHIKZ087, PHIKZ128, PHIKZ161, ... (8 entities in total)
• Functional Keywords: baseplate, inner peripheral, viral protein
• Biological source: Pseudomonas phage phiKZ; More
• Total number of polymer chains: 28
• Total formula weight: 1392215.55

Authors

Xiao, H.,Peng, Z.,Zhou, J.,Liu, H. (deposition date: 2025-11-18, release date: 2026-02-11, Last modification date: 2026-04-29)

Primary citation

Xiao, H.,Peng, Z.,Zhou, J.,Chen, Y.,Peng, Y.,Tang, Y.,Li, T.,Chen, W.,Huang, S.Y.,Cheng, L.,Liu, H.
Structural atlas of the intact jumbo phage phiKZ.
Nat Commun, 2026

PubMed Abstract: Jumbo phage phiKZ, a key model for studying phage nucleus formation and bacterial defense mechanisms, possesses a highly complex tail machine that is essential for infection. Here, we present the structural atlas of the intact jumbo phage phiKZ by cryo-EM, thereby identifying 40 constituent proteins and unveiling its modular architecture. The virion, with a length of approximately 360 nm, is comprised of an icosahedral capsid of 2520 polypeptide chains from 11 proteins, and a massive tail machine of over 900 polypeptide chains from 29 proteins. The tail features a unique, multi-layered neck and a highly elaborate baseplate. The neck is reinforced by whisker-like proteins and anchors the contractile tail, which terminates in the baseplate. The baseplate is constituted by a central hub, an inner periphery of interlocking wedge heterotrimers and hexagonal rings, and an outer periphery with a striking hexagonal star configuration. This intricate peripheral region of the baseplate serves as an extended platform for twelve peripheral fibers, which mediate host cell adsorption. Our findings provide a structural framework for understanding jumbo phage assembly and infection, thus contributing to the foundation for future functional studies and rational engineering of these phages for potential therapeutic applications.

PubMed: 41974715
DOI: 10.1038/s41467-026-71561-2

Experimental method

ELECTRON MICROSCOPY (3.65 Å)