Armata Publishes Near-Atomic Structural Atlas of Pseudomonas Phage Ar-KM, Illuminating Genome Ejection Mechanism
核心洞察
Armata Pharmaceuticals announced a Journal of Molecular Biology paper presenting an integrative structural atlas of Ar-KM (搜索), a phiKMV-like bacteriophage targeting Pseudomonas aeruginosa (搜索).
Using cryo-electron microscopy, proteomics and bioinformatics, researchers captured three distinct phage particle states and built atomic models for eleven structural proteins at near-atomic resolution.
The work identifies an enzyme activity aiding bacterial cell envelope penetration and a previously unrecognized protein enabling coordinated genome release and delivery.
Armata Pharmaceuticals, Inc. (NYSE American: ARMP) announced on Sept. 3, 2026 the publication of a peer-reviewed paper in the Journal of Molecular Biology that provides a detailed structural view of Ar-KM (搜索), a phiKMV-like bacteriophage targeting Pseudomonas aeruginosa (搜索) — the pathogen addressed by the company's AP-PA02 program. The paper, titled "Insights into Genome Ejection by a Therapeutic phiKMV-like Bacteriophage," presents an integrative structural atlas of the phage and offers mechanistic insight into how it remains stable before infection and delivers its genome once it encounters a bacterial host.
AP-PA02 is an inhaled bacteriophage product candidate that has completed Phase 2 clinical studies in both cystic fibrosis (搜索) (CF) and non-CF bronchiectasis (搜索) (NCFB) patients with chronic pulmonary P. aeruginosa infection.
Three Phage States Captured From a Single Preparation
Using cryo-electron microscopy, proteomics and bioinformatics, the researchers captured three distinct states of the phage particle from a single purified preparation and built atomic models for eleven structural proteins at near-atomic resolution. According to the company, the work explains how Ar-KM (搜索) keeps its genome securely packaged before infection, identifies an enzyme activity that helps the phage penetrate the bacterial cell envelope, and characterizes a previously unrecognized protein that enables the coordinated release and delivery of the genome into the bacterium.
"Stability before infection and efficient genome delivery at the point of infection are fundamental characteristics of a viable phage therapeutic, and this work provides important new insight into how Ar-KM (搜索) can achieve both," said Dr. Deborah Birx, Chief Executive Officer of Armata and a co-author of the paper.
Collaboration Yields Fourth Pseudomonas Phage Publication
Birx said the collaboration with Dr. Cingolani's group is helping Armata build a deeper understanding of the structural biology and mechanisms that underpin phage activity and can inform rational development of its anti-infective pipeline. She noted the paper marks the fourth publication from the collaboration and the fourth characterizing the company's Pseudomonas aeruginosa (搜索) phages, adding that Armata is now extending the work to cryo-EM reconstruction of its proprietary Staphylococcus aureus (搜索) phages.
"The exceptional resolution achieved in these studies is also supported by our proprietary purification processes, which enable the high quality pure phage preparations required for high-resolution structural analysis," Birx said. "We believe applying these capabilities across our portfolio can strengthen our understanding of phage mechanism of action and support the development of differentiated therapies targeting difficult-to-treat pathogens."
Structural Changes Drive Genome Delivery
Dr. Gino Cingolani, Anderson Family Endowed Chair in Medical Education, Research & Patient Care and Professor in the Department of Biochemistry and Molecular Genetics at The University of Alabama at Birmingham, is the senior author of the paper. He described the study as building on a productive collaboration with Armata and providing a detailed structural view of a bacteriophage that has advanced through clinical development as a therapeutic candidate against P. aeruginosa.
"Using state-of-the-art cryo-electron microscopy, comparative genomics and mass spectrometry, we characterized Ar-KM (搜索) at near-atomic resolution and gained new insight into how its structure enables it to remain stable before infection while rapidly delivering its genome once it encounters a bacterial host," Cingolani said. "We found that Ar-KM securely packages its genetic material within the phage particle and then undergoes a coordinated series of structural changes that enable the genome to be released and delivered into the bacterium. We also identified an enzymatic activity that helps the phage penetrate the bacterial cell envelope, an important step in the infection process."
Cingolani added that the findings together provide a clearer understanding of how Ar-KM (搜索) remains stable until it reaches its target and then efficiently transitions into infection mode, and that the insights help connect the fundamental biology of the phage with characteristics important to the development of effective phage therapies, including stability, infectivity and efficient genome delivery.
The full paper appears in the Journal of Molecular Biology (J Mol Biol. 2026 Nov 1; 438(21):169993).
Pipeline Context
Armata is a late clinical-stage biotechnology company focused on the development of high-purity, pathogen-specific bacteriophage therapeutics for the treatment of antibiotic-resistant and difficult-to-treat bacterial infections using its proprietary bacteriophage-based technology. The company is developing and advancing a broad pipeline of natural and synthetic phage candidates, including clinical candidates for Pseudomonas aeruginosa (搜索), S. aureus and other important pathogens. Armata states that it is committed to advancing phage therapy with drug development expertise spanning bench to clinic, including in-house phage-specific cGMP manufacturing to support full commercialization.