Improved Sample Preparation Method for Protein and Peptide Identification from Human Hair

Area of Science:

• Proteomics
• Forensic Science
• Biochemistry

Background:

• Direct extraction (DE) is a rapid protein extraction method from hair.
• Previous DE workflows coupled with in-gel digestion were time-consuming.
• Genetically variant peptides (GVPs) are crucial for human identification in forensics.

Purpose of the Study:

• To optimize and evaluate a bead-based SP3 method for hair protein analysis following DE.
• To compare the DE-SP3 workflow against traditional in-gel digestion and other in-solution digestion methods.
• To assess the impact of the DE-SP3 workflow on protein and GVP discovery in human hair.

Main Methods:

• Proteins were extracted from hair using the direct extraction (DE) method.
• The SP3 (Single-Pot Solid-Phase-ச்சி) method was optimized for hair proteins after DE.
• The DE-SP3 workflow was compared to in-gel digestion and other in-solution digestion techniques.
• Mass spectrometry was used for protein and GVP identification.

Main Results:

• The DE-SP3 workflow significantly improved protein discovery compared to previous methods.
• GVP discovery was enhanced, with approximately three times the speed of in-gel digestion.
• The DE-SP3 method required less instrument time and increased the number of identified proteins and GVPs.
• DE-SP3 demonstrated superior sequence coverage and higher peptide abundances among tested methods.

Conclusions:

• The optimized DE-SP3 workflow offers a faster and more sensitive approach for human hair proteomic analysis.
• This method significantly enhances the identification of proteins and GVPs, with strong implications for forensic applications.
• DE-SP3 provides a more efficient alternative to traditional gel-based methods for hair protein analysis.