PICarver: a software tool and strategy for peptides isoelectric focusing

Area of Science:

• Proteomics
• Analytical Chemistry
• Bioinformatics

Background:

• Isoelectric focusing (IEF) is increasingly used as a primary separation technique in shotgun proteomics.
• Current IEF methods result in uneven peptide distribution across fractions, hindering analysis.
• Theoretical peptide distribution by isoelectric point (pI) is heterogeneous, contrasting with experimental fractionation.

Purpose of the Study:

• To develop a novel computational tool and strategy for optimizing peptide fractionation in IEF-based shotgun proteomics.
• To achieve a more even distribution of peptides per fraction, enhancing analytical throughput and accuracy.
• To introduce a method for calibrating pH gradients and improving prediction precision.

Main Methods:

• Development of the pICarver software tool utilizing theoretical and experimental peptide distribution data.
• Creation of isoelectric point fluorescent peptide markers for pH gradient calibration.
• Integration of pICarver with experimental data for enhanced fractionation scheme generation.

Main Results:

• The pICarver strategy generates fractionation schemes with significantly more even peptide distribution.
• The software reduces the number of fractions required by merging peptide-poor regions, increasing throughput.
• Fluorescent peptide markers improved the precision of pICarver predictions and enabled pH gradient calibration.

Conclusions:

• The pICarver tool and strategy represent a significant advancement in IEF-based shotgun proteomics.
• This approach enhances analytical efficiency, accuracy, and the detection of post-translational modifications.
• The pICarver software is freely accessible, promoting wider adoption in the research community.