Optimized fast and sensitive acquisition methods for shotgun proteomics on a quadrupole orbitrap mass spectrometer

Area of Science:

• Proteomics
• Mass Spectrometry
• Analytical Chemistry

Background:

• Mass spectrometry advances drive proteomics.
• The quadrupole Orbitrap (Q Exactive) enables fast, high-resolution tandem mass spectra acquisition.
• Parallel operation enhances data acquisition speed.

Purpose of the Study:

• Optimize data-dependent acquisition methods for the Q Exactive.
• Assess "fast" versus "sensitive" scanning for proteome coverage.
• Determine optimal acquisition strategies based on sample load and analytical goals.

Main Methods:

• Comparative analysis of "fast" (95 ms) and "sensitive" (156 ms) HCD scanning methods.
• Evaluation using stable isotope labeled yeast proteome.
• Application to complex mammalian whole cell lysates with varying LC gradient times (1-3 h).

Main Results:

• For sample loads >125 ng, fast scanning (95 ms) identified >2000 yeast proteins in 1 hour.
• For sample loads <125 ng, sensitive scanning (156 ms) identified 30% more proteins/peptides.
• Sensitive scanning with a 3h LC gradient identified >4000 proteins from 1 μg HeLa digest, outperforming fast scanning.

Conclusions:

• Peptide identification on Q Exactive depends on sample amount, acquisition speed, and data quality.
• Tailored acquisition methods are crucial for different sample loads and analytical preferences.
• Optimized methods enhance proteome coverage and analytical efficiency.