Large-Scale Quantitative Cross-Linking and Mass Spectrometry Provides New Insight on Protein Conformational...

Area of Science:

• Biochemistry
• Structural Biology
• Proteomics

Background:

• Proteins exist in multiple conformational states in vivo, enabling diverse functional roles.
• These states are influenced by factors like alternative conformations, post-translational modifications (PTMs), and binding partners.
• Quantitative chemical cross-linking coupled with mass spectrometry (QCXL-MS) measures relative cross-link abundance across samples.

Purpose of the Study:

• To cluster intra-protein cross-links based on their quantitative data across diverse samples.
• To identify cross-links predominantly originating from specific protein conformational states.
• To provide a large-scale view of cross-links associated with protein conformational ensembles.

Main Methods:

• Utilized quantitative cross-linking data from the public XLinkDB database.
• Clustered intra-protein cross-links based on their quantitation across multiple compared samples.
• Aligned clustered cross-links with protein structures to assess their origin.

Main Results:

• Successfully clustered intra-protein cross-links according to their quantitative profiles.
• Provided the first large-scale grouping of cross-links by their predominant originating protein conformational states.
• Demonstrated a method to align these cross-link clusters with protein structures.

Conclusions:

• Quantitative cross-linking data can be used to infer protein conformational states.
• Cross-link clustering offers a novel approach to understanding protein dynamics and function.
• This method facilitates the assessment of cross-links derived from specific protein structures.