1SPF:
reference: The NMR structure of the pulmonary surfactant-associated polypeptide SP-C in an apolar solvent contains a valyl-rich alpha-helix., Johansson J, Szyperski T, Curstedt T, Wuthrich K, Biochemistry 1994 May 17;33(19):6015-23. PMID: 8180229

This OCA Structure page
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