A novel tail fiber protein triggers phage DNA ejection by recognizing lipopolysaccharides of K54 hypervirulent Klebsiella pneumoniae

作者：Ming Yin, Li Cao, Yu Fu, Yanjun Lu, Yi Yan, Qian Li, Li Xiang, Tiejun Zhou, Huan Chen, Ying Li, Luhua Zhang · 发表于：Microbiology Spectrum · 年份：2025 · DOI：10.1128/spectrum.02171-25 · 被引用次数：6 · 研究领域：Bacteriophages and microbial interactions、Antibiotic Resistance in Bacteria、Bacterial Genetics and Biotechnology

ABSTRACT Bacteriophage (phage) therapy is a promising alternative antibacterial approach for treating infectious diseases by hv Kp . However, there has been a lack of studies on the host recognition and infection initiation of hv Kp phages. In this work, we found that both capsular polysaccharide (CPS) and lipopolysaccharide (LPS) of strain SCNJ1 are essential for phage infection, and mutations in genes associated with the CPS or LPS biosynthesis pathway conferred phage resistance. These CPS-related mutants, but not LPS-related mutants, showed virulence attenuation and significantly reduced colonization in mice. We demonstrate that CPS serves as the primary receptor for phage adsorption and can be cleaved by phage depolymerase Dep-Y. Phage DNA ejection was specifically triggered by purified LPS, rendering LPS a secondary receptor during the phage infection process. Furthermore, mutant phages capable of infecting the LPS-related mutant strain were isolated, leading to the identification of a novel tail fiber protein named TFP_Y, which can interact with LPS to initiate phage genome ejection. In conclusion, we propose a molecular model for phage infection in the hv Kp strain SCNJ1. In this model, the phage utilizes both the CPS and LPS as receptors to initiate an infection in hv Kp : the phage attaches to the bacterial cell surface; depolymerase Dep-Y degrades the host CPS to expose the LPS; and TFP_Y interacts with LPS, leading to the ejection of phage genome DNA. These finding...