Single-stranded DNA binding protein from bacteriophage cf: characterization, gene localization and protein-ssDNA...

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Filamentous bacteriophages are important tools in molecular biology.
• Single-stranded DNA binding proteins play crucial roles in phage replication and assembly.
• The GVP protein of bacteriophage cf has not been extensively characterized.

Purpose of the Study:

• To purify and characterize the single-stranded DNA binding protein (GVP) of filamentous bacteriophage cf.
• To investigate the structure and properties of the GVP-ssDNA complex.
• To compare the cf GVP-ssDNA complex with that of other filamentous phages, such as M13.

Main Methods:

• N-terminal amino acid sequencing
• Denaturing and native protein gel electrophoresis
• Gene sequencing and identification
• Density gradient centrifugation
• Transmission electron microscopy (TEM)
• Computer modeling

Main Results:

• The cf GVP is a 98 amino acid protein (10.8 kDa) that forms a homodimer.
• The GVP gene is located in gene V, similar to M13 phage.
• The cf GVP shows sequence homology to other filamentous phage ssDNA binding proteins.
• The cf GVP-ssDNA complex is approximately 1200 nm long and 9 nm in diameter.
• The cf GVP-ssDNA complex lacks a helical pattern seen in M13 and appears more rigid.
• Computer modeling suggests C-terminal amino acid differences contribute to structural variations.

Conclusions:

• The cf GVP is a well-characterized ssDNA binding protein with unique structural and biophysical properties.
• The cf GVP-ssDNA complex's distinct morphology and rigidity are likely influenced by its C-terminal amino acid sequence.
• This study provides insights into the diversity of ssDNA binding proteins and their complexes in filamentous phages.