Instrument-Software Synergy in Proteomics: Systematic Evaluation across Mass Spectrometry Platforms, Search Engines, and Rescoring Methods.

Mass spectrometry-based proteomics has advanced through parallel improvements in instrumentation (mass spectrometers) and software (data analysis), yet whether these improvements interact synergistically or provide diminishing returns remains unclear. Here, we systematically evaluate instrument-software coevolution across eight mass spectrometry platforms, three generations of search engines, and multiple rescoring approaches, yielding 72 unique instrument-software combinations spanning from 2004 to 2024. Our results reveal that instrumentation and software improvements produce synergistic rather than substitutive benefits. Here, machine learning-based rescoring consistently recovers identifications from low-intensity precursors that produce noisier, more challenging spectra. Crucially, because of increased sensitivity and speed, modern instruments detect more low-intensity precursors, thereby increasing the population of challenging spectra for which rescoring provides the greatest benefit. However, this expanded detection depth comes at a cost: recovered low-abundance peptides exhibit inherently higher quantification error, creating a fundamental trade-off between proteome coverage and quantification accuracy. Together, these findings provide a systematic overview of how instrument and software advances have jointly shaped proteomics performance over the past two decades.