5VQF:
reference: Prodomain-Growth Factor Swapping in the Structure of pro-TGF-beta1., Zhao B, Xu S, Dong X, Lu C, Springer TA, J Biol Chem. 2017 Nov 5. pii: jbc.M117.809657. doi: 10.1074/jbc.M117.809657. PMID: 29109152

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