2LCR:
reference: Structure of the Alk1 extracellular domain and characterization of its bone morphogenetic protein (BMP) binding properties., Mahlawat P, Ilangovan U, Biswas T, Sun LZ, Hinck AP, Biochemistry. 2012 Aug 14;51(32):6328-41. Epub 2012 Aug 2. PMID: 22799562

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