Related Experiment Video
Updated: Jul 14, 2026

Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
Identification of the major protein component of the pneumococcal eclipse complex
Donald A Morrison1, Isabelle Mortier-Barrière, Laetitia Attaiech
1Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, 900 South Ashland Ave., Chicago, IL 60607, USA. damorris@uic.edu
Researchers identified the SsbB protein as a key component of the eclipse complex during Streptococcus pneumoniae genetic transformation. This protein associates with donor DNA inside competent cells, aiding in the transformation process.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Genetic transformation is crucial for bacterial adaptation and evolution.
- During transformation, donor DNA forms an 'eclipse complex' with intracellular proteins.
- The identity of proteins within this complex in Streptococcus pneumoniae was previously unknown.
Purpose of the Study:
- To identify the primary protein component of the eclipse complex in Streptococcus pneumoniae.
- To elucidate the role of this protein in genetic transformation.
Main Methods:
- Utilized Western blotting techniques.
- Analyzed protein cofractionation with donor DNA during genetic transformation.
- Investigated protein complexes within competent Streptococcus pneumoniae cells.
Main Results:
- Identified the SsbB protein as the principal protein associated with donor DNA in the eclipse complex.
- SsbB has a molecular mass of 15 to 20 kDa.
- Confirmed SsbB's cofractionation with donor DNA.
Conclusions:
- SsbB is a critical protein involved in the early stages of Streptococcus pneumoniae genetic transformation.
- The identification of SsbB advances our understanding of DNA uptake and processing mechanisms in bacteria.
More Related Videos
Related Concept Videos
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...

