Heme ladder, a direct molecular weight marker for immunoblot analysis

Emerging techniques of western blotting for purification and analysis of protein

Background

Western blotting is frequently employed in molecular techniques like Proteomics and Biology. Because it is a sequential framework, differences and inaccuracies could even take place at any stage, decreasing this particular method's reproducibility and reliability.

Main text

New approaches, like automated microfluid western blotting, DigiWest, single cell resolution, microchip electrophoresis, and capillary electrophoresis, were all implemented to reduce the future conflicts linked with the western blot analysis approach. Discovery of new in devices and higher susceptibility for western blots gives innovative opportunities to expand Western blot’s clinical relevance. The advancements in various region of west blotting included in this analysis of transfer of protein and validation of antibody are described.

Conclusion

This paper describes another very developed strategy available as well as demonstrated the correlation among Western blotting techniques of the next generation and their clinical implications. In this review, the different techniques of western blotting and their improvement in different stages have been discussed.

The Penn State Protein Ladder system for inexpensive protein molecular weight markers

We have created the Penn State Protein Ladder system to produce protein molecular weight markers easily and inexpensively (less than a penny a lane). The system includes plasmids which express 10, 15, 20, 30, 40, 50, 60, 80 and 100 kD proteins in E. coli. Each protein migrates appropriately on SDS-PAGE gels, is expressed at very high levels (10–50 mg per liter of culture), is easy to purify via histidine tags and can be detected directly on Western blots via engineered immunoglobulin binding domains. We have also constructed plasmids to express 150 and 250 kD proteins. For more efficient production, we have created two polycistronic expression vectors which coexpress the 10, 30, 50, 100 kD proteins or the 20, 40, 60, 80 kD proteins. 50 ml of culture is sufficient to produce 20,000 lanes of individual ladder protein or 3750 lanes of each set of coexpressed ladder proteins. These Penn State Protein Ladder expression plasmids also constitute useful reagents for teaching laboratories to demonstrate recombinant expression in E. coli and affinity protein purification, and to research laboratories desiring positive controls for recombinant protein expression and purification.

Protein purification and analysis: next generation Western blotting techniques

INTRODUCTION

Western blotting is one of the most commonly used techniques in molecular biology and proteomics. Since western blotting is a multistep protocol, variations and errors can occur at any step reducing the reliability and reproducibility of this technique. Recent reports suggest that a few key steps, such as the sample preparation method, the amount and source of primary antibody used, as well as the normalization method utilized, are critical for reproducible western blot results. Areas covered: In this review, improvements in different areas of western blotting, including protein transfer and antibody validation, are summarized. The review discusses the most advanced western blotting techniques available and highlights the relationship between next generation western blotting techniques and its clinical relevance. Expert commentary: Over the last decade significant improvements have been made in creating more sensitive, automated, and advanced techniques by optimizing various aspects of the western blot protocol. New methods such as single cell-resolution western blot, capillary electrophoresis, DigiWest, automated microfluid western blotting and microchip electrophoresis have all been developed to reduce potential problems associated with the western blotting technique. Innovative developments in instrumentation and increased sensitivity for western blots offer novel possibilities for increasing the clinical implications of western blot.

A Secondary Antibody-Detecting Molecular Weight Marker with Mouse and Rabbit IgG Fc Linear Epitopes for Western Blot Analysis

Molecular weight markers that can tolerate denaturing conditions and be auto-detected by secondary antibodies offer great efficacy and convenience for Western Blotting. Here, we describe M&R LE protein markers which contain linear epitopes derived from the heavy chain constant regions of mouse and rabbit immunoglobulin G (IgG Fc LE). These markers can be directly recognized and stained by a wide range of anti-mouse and anti-rabbit secondary antibodies. We selected three mouse (M1, M2 and M3) linear IgG1 and three rabbit (R1, R2 and R3) linear IgG heavy chain epitope candidates based on their respective crystal structures. Western blot analysis indicated that M2 and R2 linear epitopes are effectively recognized by anti-mouse and anti-rabbit secondary antibodies, respectively. We fused the M2 and R2 epitopes (M&R LE) and incorporated the polypeptide in a range of 15–120 kDa auto-detecting markers (M&R LE protein marker). The M&R LE protein marker can be auto-detected by anti-mouse and anti-rabbit IgG secondary antibodies in standard immunoblots. Linear regression analysis of the M&R LE protein marker plotted as gel mobility versus the log of the marker molecular weights revealed good linearity with a correlation coefficient R² value of 0.9965, indicating that the M&R LE protein marker displays high accuracy for determining protein molecular weights. This accurate, regular and auto-detected M&R LE protein marker may provide a simple, efficient and economical tool for protein analysis.

Cytochrome c heme lyase can mature a fusion peptide composed of the amino-terminal residues of horse cytochrome c

It is shown that cytochrome c heme lyase (CCHL) attaches heme covalently to peptides composed of the N-terminal segment of cyt c fused to a non-heme containing protein, lending insight into the substrate specificity of CCHL and providing a new route to artificial heme proteins.