Complete nucleotide sequence of the gene encoding bacteriophage E endosialidase: implications for K1E endosialidase...

Area of Science:

• Microbiology
• Virology
• Molecular Biology

Background:

• Bacteriophage E infects Escherichia coli strains with the alpha-2,8-linked polysialic acid K1 capsule.
• The phage's endosialidase enzyme is crucial for initial attachment to the host bacterium.

Purpose of the Study:

• To purify and characterize the Bacteriophage E endosialidase.
• To identify the gene encoding the endosialidase and elucidate its structure and function.

Main Methods:

• Purification of Bacteriophage E endosialidase.
• Determination of N-terminal amino acid sequences.
• Design of synthetic oligonucleotide probes for gene identification.
• DNA sequencing of the endosialidase gene.
• Sequence homology analysis with other endosialidases.

Main Results:

• The endosialidase gene encodes a 90 kDa polypeptide, processed to a mature 74 kDa protein, likely forming a trimer.
• A putative upstream promoter region with homology to bacteriophage SP6 promoter was identified.
• The K1E endosialidase shares 84% identity in a central 500-amino acid region with K1F endosialidase.
• Both enzymes contain two sialidase sequence motifs, suggesting a role in polysialic acid binding and hydrolysis.

Conclusions:

• The study elucidated the genetic basis and structural features of Bacteriophage E endosialidase.
• The findings highlight the conserved nature of endosialidases and their functional domains in phage-host interactions.
• This research provides insights into the molecular mechanisms of bacteriophage infection and potential therapeutic applications.