dig

dig analyzes protein sequences by digesting them with trypsin and measuring resulting peptides using a 9.4 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer to enable peptide-based protein identification and characterization.

Key Features:

• High-Resolution Mass Spectrometry: Utilizes a 9.4 Tesla FTICR instrument providing ultra-high mass resolving power and accuracy for precise peptide mass measurement.
• Tryptic Digestion: Proteins are enzymatically digested with trypsin to generate reproducible peptide fragments.
• Complex Mixture Analysis: Applied to mixtures including equine cytochrome c, equine myoglobin, bovine serum albumin, and human plasma, enabling analysis of diverse biological samples.
• Direct Analysis without Prior Separation: Enables examination of complex biological mixtures without prior chromatographic separation steps.
• Automated Data Processing: Employs computer programs to reduce thousands of spectral peaks into isotopic clusters and unique masses.

Scientific Applications:

• Protein Identification and Characterization: Matches peptide masses to known protein sequences with high accuracy (mass measurement errors less than 10 ppm).
• Coverage Analysis: Provides substantial sequence coverage, exemplified by 93% coverage for serum albumin and 41% for transferrin in human plasma.
• Error Distribution Analysis: Produces mass measurement errors that are normally distributed with a standard deviation of 1.7 ppm.

Methodology:

Proteins are digested with trypsin, peptides are measured by a 9.4 Tesla FTICR mass spectrometer, and computer programs cluster isotopic peaks and extract unique masses from complex spectra.