Terminomics Methodologies and the Completeness of Reductive Dimethylation: A Meta-Analysis of Publicly Available Datasets

• Main Authors: Mariella Hurtado Silva, Iain J. Berry, Natalie Strange, Steven P. Djordjevic, Matthew P. Padula
• Format: Article
• Language: English
• Published: MDPI AG 2019-03-01
• Series: Proteomes
• Subjects: terminomics; mass spectrometry; amine labelling
• Online Access: https://www.mdpi.com/2227-7382/7/2/11

Methods for analyzing the terminal sequences of proteins have been refined over the previous decade; however, few studies have evaluated the quality of the data that have been produced from those methodologies. While performing global N-terminal labelling on bacteria, we observed that the labelling was not complete and investigated whether this was a common occurrence. We assessed the completeness of labelling in a selection of existing, publicly available N-terminomics datasets and empirically determined that amine-based labelling chemistry does not achieve complete labelling and potentially has issues with labelling amine groups at sequence-specific residues. This finding led us to conduct a thorough review of the historical literature that showed that this is not an unexpected finding, with numerous publications reporting incomplete labelling. These findings have implications for the quantitation of N-terminal peptides and the biological interpretations of these data.