Recombinant Proteins
Product List
SPA-Cys
Staphylococcal Protein-A Cys Recombinant
SPA-Cys His
Staphylococcal Protein-A Cys Recombinant, His Tag
SPA-Cys Long
Staphylococcal Protein-A Cys Long Form Recombinant
Introduction
Protein A is a 42 kDa surface protein originally found in the cell wall of the bacteria Staphylococcus aureus. It is encoded by the spa gene and is known for its ability to bind immunoglobulins, particularly the Fc region of IgG .
Protein G is derived from Streptococcus species and also binds to the Fc region of IgG. It has a broader binding range compared to Protein A, making it useful for different species and subclasses of IgG .
Protein A/G is a recombinant fusion protein that combines the IgG-binding domains of both Protein A and Protein G. This fusion enhances its binding capabilities, making it ideal for a wide range of IgG subclasses from various species .
Key Biological Properties:
- Protein A: Composed of five homologous Ig-binding domains that fold into a three-helix bundle. It binds to the heavy chain within the Fc region of most immunoglobulins .
- Protein G: Contains multiple IgG-binding domains and binds more strongly to certain subclasses of IgG .
- Protein A/G: Combines properties of both Protein A and Protein G, providing versatile binding capabilities .
Expression Patterns and Tissue Distribution:
Primary Biological Functions:
- Protein A: Disrupts opsonization and phagocytosis by binding IgG molecules in the wrong orientation .
- Protein G: Enhances immune response by binding to a broader range of IgG subclasses .
- Protein A/G: Combines the functions of both Protein A and Protein G, making it highly effective in immune response modulation .
Role in Immune Responses and Pathogen Recognition:
Mechanisms with Other Molecules and Cells:
- Protein A: Binds to the Fc region of IgG, disrupting normal antibody function .
- Protein G: Binds to the Fc region of IgG, enhancing immune response .
- Protein A/G: Combines the binding mechanisms of both Protein A and Protein G .
Binding Partners and Downstream Signaling Cascades:
Regulatory Mechanisms Controlling Expression and Activity:
- Protein A: Regulation controlled by DNA topology, cellular osmolarity, and a two-component system called ArlS-ArlR .
- Protein G: Expression regulated by environmental factors in Streptococcus .
- Protein A/G: Recombinant expression regulated by genetic engineering techniques .
Transcriptional Regulation and Post-Translational Modifications:
In Biomedical Research:
- Protein A: Used in antibody purification and immunoprecipitation .
- Protein G: Preferred for purifying antibodies from various species .
- Protein A/G: Ideal for a wide range of immunological studies .
Diagnostic Tools:
- Protein A: Utilized in diagnostic assays to detect antibodies .
- Protein G: Used in diagnostic kits for its broad binding range .
- Protein A/G: Employed in various diagnostic applications due to its versatility .
Therapeutic Strategies:
Role Throughout the Life Cycle:
- Protein A: Plays a role in the survival and virulence of Staphylococcus aureus .
- Protein G: Contributes to the pathogenicity of Streptococcus species .
- Protein A/G: Used in research to study protein interactions throughout various stages of life .
From Development to Aging and Disease:
