1A3I:
reference: X-ray crystallographic determination of a collagen-like peptide with the repeating sequence (Pro-Pro-Gly)., Kramer RZ, Vitagliano L, Bella J, Berisio R, Mazzarella L, Brodsky B, Zagari A, Berman HM, J Mol Biol 1998 Jul 24;280(4):623-38. PMID: 9677293

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