Distinguishing N-Terminal Methylation from Near-isobaric Modifications by Statistical Analysis of Mass Error Distributions of Fragment Ions

ABSTRACT: alpha-N-terminal methylation is an understudied post-translational modification with presumed functions involving protein-protein and/or protein-DNA interaction. The covalent addition of mono-, di-, trimethyl groups to free alpha-amino group has proven to be difficult to profile globally by mass spectrometry due to trace endogenous amount and interference from near-isobaric modifications such as Nt-acetylation, even after N-terminome enrichment. To address this problem, we assume that in each MS2 spectrum b-ions will have a different mass error distribution compared to y-ions if the spectrum is falsely assigned to near-isobaric Nt-modification and exploit this statistically to correct the Nt-modification, a procedure we name as mass error test (MET)

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (ncbitaxon:9606)

SUBMITTER: Cheolju lee  

PROVIDER: MSV000096415 | MassIVE | Thu Nov 14 05:38:00 GMT 2024

SECONDARY ACCESSION(S): PXD057893

REPOSITORIES: MassIVE