1U0S:
reference: In different organisms, the mode of interaction between two signaling proteins is not necessarily conserved., Park SY, Beel BD, Simon MI, Bilwes AM, Crane BR, Proc Natl Acad Sci U S A 2004 Aug 10;101(32):11646-51. Epub 2004 Aug 2. PMID: 15289606

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