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Updated: May 21, 2026
08:38
Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells
Published on: March 3, 2015
How many protein-protein interactions types exist in nature?
Leonardo Garma1, Srayanta Mukherjee, Pralay Mitra
1Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America.
Plos One
|June 22, 2012
Summary
The universe of protein interactions is finite, with an estimated 4,000 possible quaternary folds. Current data covers only 42% of these protein complex structures, requiring extensive future research.
Area of Science:
- Structural Biology
- Bioinformatics
- Computational Biology
Background:
- Protein quaternary structure describes the arrangement of multiple protein subunits in a complex.
- Understanding the diversity of protein-protein interactions is crucial for deciphering biological functions.
Purpose of the Study:
- To determine if the number of protein-protein interactions is limited.
- To estimate the total number of distinct quaternary folds in nature.
Main Methods:
- All-to-all sequence and structure comparisons of protein complexes from the Protein Data Bank (PDB).
- Development of a statistical model to relate quaternary families and folds.
- Estimation of the total number of possible protein-protein interactions.
Main Results:
- Categorized PDB protein complexes into 3,629 families and 1,761 folds.
- Estimated the total number of possible protein-protein interactions to be approximately 4,000.
- Concluded that current repositories contain only 42% of known quaternary folds.
Conclusions:
- The diversity of protein quaternary structures is finite and estimated at around 4,000 folds.
- Significant experimental effort is needed to achieve complete coverage of known protein complex structures.
- Findings impact protein complex modeling and the structural genomics of protein interactions.
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