Name: reading peptide fragments with tandem ms
Uploaded: 2023-04-30T11:59:02.000Z
Duration: 1 min 33 s
Channel: JoVE

Unlike MALDI-TOF, tandem mass spectrometry, or MS/MS, employs two mass analyzers placed in series, separated by a collision cell. This technique can identify the amino acid sequence of a peptide from a complex mixture for detailed analysis.
First, an electrospray ionizer generates peptide ions and accelerates them to the first mass analyzer like a quadrupole. This analyzer acts as a mass filter allowing selection of a single peptide ion called a precursor ion of a specific mass-to-charge ratio.
Once inside the collision cell, the selected peptide ion collides with the gas molecules, primarily breaking the peptide bonds, and generating smaller ions.
These ions move into the second mass analyzer like a time of flight that separates ions based on their mass-to-charge ratio.
The obtained product-ion spectrum helps identify the peptide&#39;s amino acid sequence.
Combining MS/MS with liquid chromatography aids in continuous peptide analysis from complex biological samples.
MS/MS can also characterize lipids, identify post-translational protein modifications, and detect low levels of disease-specific biomarkers in biological samples.

peptide identification using tandem mass spectrometry

Peptide Identification Using Tandem Mass Spectrometry

Tandem mass spectrometry, also known as MS/MS or MS2, is an analytical technique that employs two mass analyzers. Essentially it is a series of mass spectrometers that helps isolate a particular biomolecule and then helps study its chemical properties.
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides&#8217; amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of proteomics.
The different peptides obtained after enzymatic digestion can be further separated as much as possible as per the physical size and/or chemical properties using sophisticated instruments like gel electrophoresis or liquid chromatography.
This first stage of MS/MS allows the peptides to separate based on their mass-to-charge ratio, followed by breaking or fragmenting the selected peptide ion in the collision cell. The second mass analyzer helps build the fragmentation pattern to determine the sequence or identify the protein.
Studying the results and deducing the peptide sequence is extremely important once the spectrum is obtained. For this, numerous protein database search algorithms and bioinformatics tools help in sample elucidation from the obtained spectrum. In the case of an unknown protein, the obtained spectrum shows numerous overlapping fragments. However, as the spectral pattern is unique for a given protein, the analysis software compares the obtained spectrum with a database of known peptide sequences, thus elucidating the unknown protein from the overlapping fragments.
Different analyzer combinations can be used to create hybrid MS/MS instruments and thus increase the sensitivity of the results. For example, quadrupole time-of-flight (QTOF) is a combination of quadrupole and time-of-flight mass analyzers. The triple quadrupole mass spectrometer contains two quadrupole mass analyzers separated by a non-mass resolving quadrupole collision cell for fragmentation.
In newborn screening, the tandem MS uses dried blood-spot samples to help in a comprehensive assessment of inborn metabolic disorders like phenylketonuria, sickle cell disease, etc. The early identification helps substantial improvement in health outcomes.

Tandem mass spectrometry, also known as MS/MS or MS2, is an analytical technique that employs two mass analyzers. Essentially it is a series of mass ...

peptide-identification-using-tandem-mass-spectrometry

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Cell Biology

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Analyzing Cells and Proteins

KEY TERMS AND CONCEPTS

reading peptide fragments with tandem ms

Tandem mass spectrometry helps identify peptides by measuring their mass and breaking them into smaller pieces. It is also called MS/MS or MS2. The method uses two mass analyzers to isolate a biomolecule and study its chemical properties.

This approach is important in proteomics, the study of proteins on a large scale. Peptides from a complex mixture are often first separated as much as possible after enzymatic digestion. Instruments such as gel electrophoresis or liquid chromatography can help separate them by physical size or chemical properties.

In the first stage of MS/MS, peptides are sorted by their mass-to-charge ratio. The selected peptide ion is then fragmented in a collision cell. The second mass analyzer records the fragmentation pattern, which helps determine the amino acid sequence or identify the protein.

Once the spectrum is collected, the next step is to interpret the results. Protein database search algorithms and bioinformatics tools compare the spectrum with known peptide sequences. This is especially useful for unknown proteins, where overlapping fragments can appear in the spectrum. Because each protein produces a unique pattern, the software can help reveal the protein from those fragments.

Hybrid MS/MS instruments can improve sensitivity by combining analyzer types. A quadrupole time-of-flight, or QTOF, pairs a quadrupole with a time-of-flight analyzer. A triple quadrupole mass spectrometer uses two quadrupole mass analyzers with a non-mass resolving collision cell between them for fragmentation.

Tandem MS also has real-world use in newborn screening. Dried blood-spot samples can be tested for inborn metabolic disorders such as phenylketonuria and sickle cell disease. Early detection can lead to better health outcomes.

Reading Peptide Fragments with Tandem MS

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Tandem mass spectrometry helps identify peptides by measuring their mass and breaking them into smaller pieces. It is also called MS/MS or MS2. The method uses two mass analyzers to isolate a biomolecule and study its chemical properties. This approach is important in proteomics, the study of proteins on a large scale. Peptides from a complex mixture are often first separated as much as possible after enzymatic digestion. Instruments such as gel electrophoresis or liquid chromatography can...

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key terms and concepts

Learn how tandem mass spectrometry separates, fragments, and matches peptide signals to identify proteins, with uses in proteomics and newborn screening.

Reading Peptide Fragments with Tandem MS | JoVE K12

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Reading Peptide Fragments with Tandem MS

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