Uncover New Insights with Post-translational Modification (PTM) Analysis

See how Platinum’s single-molecule resolution overcomes obstacles presented by other PTM analysis methods:

• Detection and Differentiation of PTMs with Platinum

  Arginine PTM analysis

  Arginine plays a critical role in protein structure and function and often mediates key interactions between protein binding partners or between proteins and DNA. The two most common arginine PTMs are citrullination and dimethylation, which respectively alter arginine into citrulline or ADMA and SDMA.

  

  ADMA and SDMA isomers share structural similarities and an identical mass, limiting their identification through traditional mass spectrometry. Likewise, determining arginine to citrulline results in a negligible mass increase. Another common method for PTM detection is antibody-based immunoassay ELISA, but only a few antibodies against arginine PTMs are commercially available, restricting its application.

  Direct detection of arginine PTMs in proteins with Platinum

  With Platinum’s single-molecule resolution and sensitivity, you can detect and differentiate arginine PTMs accurately. Peptide fragments are probed in real-time by fluorescently labeled recognizers, designed to bind on and off to their cognate N-terminal amino acid (NAA), while aminopeptidases in solution remove analyzed NAAs to expose subsequent amino acids for further recognition.
  Fluorescence lifetime, intensity, and kinetic data are collected in real-time and analyzed to determine amino acid sequence and PTM content. This novel single-molecule sequencing approach can overcome the challenges facing conventional methods through unparalleled amino acid detection.

  Using Quantum-Si’s single-molecule protein sequencing, we demonstrated how to detect citrulline and how to differentiate between dimethylated arginine residues efficiently.

  See the Data

  Platinum Can Detect and Differentiate PTMs – Download the application note to see how the process works and the PTM analysis that Platinum® delivers.

• Beyond the Genome: Identification of Protein Sequence and PTMs with Quantum-Si’s Next- Generation Protein Sequencer™ Platinum®

  To demonstrate the versatility of Platinum and the use of kinetic signatures, we sequenced various types of samples, including mixtures of recombinant proteins, peptides with post-translational modifications (PTMs), proteins immunoprecipitated from human serum, and proteins isolated from human serum via fractionation with SDS-PAGE. The resulting peptides generated distinct kinetic signatures aligned to their respective sequences, highlighting the efficacy of Quantum-Si’s sequencing platform in analyzing multi-protein mixtures at reduced input concentrations.

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