pyMS-Vis, an\nOpen-Source Python Application for Visualizing\nand Investigating Deconvoluted Top-Down Mass Spectrometric Experiments:\nA Histone Proteoform Case Study

We report the development\nof an open-source Python application\nthat provides quantitative and qualitative information from deconvoluted\nliquid-chromatography top-down mass spectrometry (LC-TDMS) data sets.\nThis simple-to-use program allows users to search masses-of-interest\nacross multiple LC-TDMS runs and provides visualization of their ion\nintensities and elution characteristics while quantifying their abundances\nrelative to one another. Focusing on proteoform-rich histone proteins\nfrom the green microalga <i>Chlamydomonas reinhardtii</i>, we were able to quantify proteoform abundances across different\ngrowth conditions and replicates in minutes instead of hours typically\nneeded for manual spreadsheet-based analysis. This resulted in extending\npreviously published qualitive observations on Chlamydomonas histone\nproteoforms into quantitative ones, leading to an exciting new discovery\non alpha-amino termini processing exclusive to histone H2A family\nmembers. Lastly, the script was intentionally developed with readability\nand customizability in mind so that fellow mass spectrometrists can\nmodify the code to suit their lab-specific needs.