Related Experiment Video
Updated: Jun 6, 2026

Analyzing DNA-Protein Interactions with Streptavidin-Based Biolayer Interferometry
Published on: January 17, 2025
Characterization of a single-stranded DNA-binding protein from Pseudomonas aeruginosa PAO1
Hau-Chern Jan1, Yen-Ling Lee, Cheng-Yang Huang
1Department of Biomedical Sciences, Chung Shan Medical University, No. 110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan.
Abstract:
Single-stranded DNA-binding protein (SSB) plays an important role in DNA metabolism, such as in DNA replication, repair, and recombination, and is essential for cell survival. We characterized the single-stranded DNA (ssDNA)-binding properties of Pseudomonas aeruginosa PAO1 SSB (PaSSB) by using fluorescence quenching measurements and electrophoretic mobility shift analysis (EMSA). Analysis of purified PaSSB by gel filtration chromatography revealed a stable tetramer in solution. In fluorescence titrations, PaSSB bound 22-32 nucleotides (nt) per tetramer depending on salt concentration. Using EMSA, we characterized the stoichiometry of PaSSB complexed with a series of ssDNA homopolymers, and the size of the binding site was determined to be 29 ± 1 nt. Furthermore, EMSA results indicated that the dissociation constants of PaSSB for the first tetramer were less than those for the second tetramer. On the basis of these biophysical analyses, the ssDNA binding mode of PaSSB is expected to be noncooperative.
More Related Videos
11:35Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants
Published on: May 4, 2018
09:04Sequence-specific and Selective Recognition of Double-stranded RNAs over Single-stranded RNAs by Chemically Modified Peptide Nucleic Acids
Published on: September 21, 2017
Related Concept Videos
Single-Strand DNA Binding Proteins
Bacterial RNA Polymerase
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
Globular and Fibrous Proteins
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Nucleoid
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to form...