Related Experiment Video
Updated: Sep 25, 2026
Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods
Published on: December 21, 2019
Identification and mutational analysis of bacteriophage PRD1 holin protein P35
Pia S Rydman1, Dennis H Bamford
1Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Finland.
Abstract:
Holin proteins are phage-induced integral membrane proteins which regulate the access of lytic enzymes to host cell peptidoglycan at the time of release of progeny viruses by host cell lysis. We describe the identification of the membrane-containing phage PRD1 holin gene (gene XXXV). The PRD1 holin protein (P35, 12.8 kDa) acts similarly to its functional counterpart from phage lambda (gene S), and the defect in PRD1 gene XXXV can be corrected by the presence of gene S of lambda. Several nonsense, missense, and insertion mutations in PRD1 gene XXXV were analyzed. These studies support the overall conclusion that the charged amino acids at the protein C terminus are involved in the timing of host cell lysis.
Insights
Researchers identified the PRD1 phage holin gene (gene XXXV), a protein crucial for progeny virus release. Mutations revealed charged amino acids at the C-terminus regulate the timing of host cell lysis.
Area of Science:
- Molecular Biology
- Virology
- Membrane Protein Function
Background:
- Holin proteins are essential phage-induced integral membrane proteins.
- They control lytic enzyme access to peptidoglycan during viral replication.
- This process is critical for the release of progeny viruses via host cell lysis.
Purpose of the Study:
- To identify and characterize the holin gene of the membrane-containing phage PRD1 (gene XXXV).
- To investigate the function and regulation of the PRD1 holin protein (P35).
- To determine the role of specific mutations in PRD1 gene XXXV on host cell lysis timing.
Main Methods:
- Identification of the PRD1 holin gene (gene XXXV).
- Functional analysis of the PRD1 holin protein (P35) and comparison with phage lambda's gene S.
- Site-directed mutagenesis (nonsense, missense, insertion) of PRD1 gene XXXV.
- Analysis of mutant phenotypes to assess impact on host cell lysis.
Main Results:
- The PRD1 holin gene (gene XXXV) and its protein product (P35, 12.8 kDa) were identified.
- PRD1 holin functions similarly to phage lambda's holin (gene S), with gene S capable of correcting PRD1 gene XXXV defects.
- Analysis of various mutations in PRD1 gene XXXV indicated that charged amino acids at the protein's C-terminus are involved in regulating the timing of host cell lysis.
Conclusions:
- The PRD1 holin gene (gene XXXV) plays a critical role in phage-mediated host cell lysis.
- The C-terminal charged amino acids of the PRD1 holin protein are key determinants for the timing of lysis.
- This study provides insights into the molecular mechanisms of viral release and holin protein function.
