bacterial viruses
DESCRIPTION
Bacterial viruses. Very complex shape, requiring 20 gene products for assembly - Capsid (head), contains linear dsDNA genome - Tail , consists of sheath plus internal tube. Bacteriophage T4. Figure 11.2. - PowerPoint PPT PresentationTRANSCRIPT
Bacterial viruses
• Very complex shape, requiring 20 gene products for assembly
• - Capsid (head), contains linear dsDNA genome
• - Tail, consists of sheath plus internal tube
Bacteriophage T4
Figure 11.2
• Phage T4 binds to E. coli by contact between its tail fibers and the outer membrane.
• - A conformational change causes sheath to contract and inject the genome into the cell.
Bacteriophage T4
Figure 11.4
Fig. 10-15
NucleasesDNA polymeraseNew sigma factors
Phage DNA
Infection
Early mRNA
Early proteins
Phage DNA replication
Middle mRNA Late mRNA
Late proteinsMiddle proteins
Self assembly
Phageheadproteins
Tail, collar, baseplate, and tailfiber proteins
Mature phage particleT4 lysozymeproduction
Lysis
252015Minutes
1050
• Progeny genomes are linked in a concatemer.
• - Cut with an offset, so that individual linear genomes have slight overlaps
Figure 11.7
Figure 11.6
Replicative Cycle of Bacteriophage T4
• Progeny genomes are linked in a concatemer.
• - Cut with an offset, so that individual linear genomes have slight overlaps
Figure 11.7
• Each phage particle is assembled by convergence of three pathways involving head, tail, and tail fibers.
Figure 11.8
Figure 11.6
Replicative Cycle of Bacteriophage T4