4INS:
reference: The structure of 2Zn pig insulin crystals at 1.5 A resolution., Baker EN, Blundell TL, Cutfield JF, Cutfield SM, Dodson EJ, Dodson GG, Hodgkin DM, Hubbard RE, Isaacs NW, Reynolds CD, et al., Philos Trans R Soc Lond B Biol Sci 1988 Jul 6;319(1195):369-456. PMID: 2905485

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