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Ten thousand interactions for the molecular biologist


Previous studies have suggested that nature is restricted to about 1,000 protein folds to perform a great diversity of functions. Here, we use protein interaction data from different sources and three-dimensional structures to suggest that the total number of interaction types is also limited, and estimate that most interactions in nature will conform to one of about 10,000 types. We currently know fewer than 2,000, and at the present rate of structure determination, it will be more than 20 years before we know a full representative set.

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Figure 1: Direct physical interactions within complexes.
Figure 2
Figure 3: Growth in the number and type of protein-protein interactions of known three-dimensional structure.


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We thank Andrej Sali (UCSF) for fruitful discussions and Peer Bork (EMBL) for useful comments on the manuscript.

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Correspondence to Robert B Russell.

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Aloy, P., Russell, R. Ten thousand interactions for the molecular biologist. Nat Biotechnol 22, 1317–1321 (2004).

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