SequestXTandem

SequestXTandem is a bioinformatics software tool used for peptide identification in mass spectrometry. It is an evolution of the SEQUEST algorithm, which was developed at the University of Washington. SequestXTandem combines the spectral matching capabilities of SEQUEST with the scoring and filtering principles found in the X!Tandem software. This integration aims to improve the accuracy and confidence of peptide identifications by leveraging the strengths of both underlying programs.

The software works by comparing experimental mass spectra obtained from a mass spectrometer against a theoretical spectrum generated from a protein sequence database. SequestXTandem assigns a score to each potential peptide match, indicating the quality of the similarity between the experimental and theoretical spectra. Higher scores generally suggest a more likely correct identification.

Key features of SequestXTandem include its ability to handle various types of post-translational modifications (PTMs), allowing for more comprehensive analysis of proteomic samples. It also incorporates advanced statistical methods for filtering and validating peptide identifications, helping researchers to distinguish between true positives and false positives. This is crucial in high-throughput proteomics experiments where large numbers of spectra are analyzed. The software is often used in conjunction with other bioinformatics tools for downstream analysis of protein abundance and functional characterization.