4DB9:
reference: Structure-based optimization of designed Armadillo-repeat proteins., Madhurantakam C, Varadamsetty G, Grutter MG, Pluckthun A, Mittl PR, Protein Sci. 2012 Jul;21(7):1015-28. doi: 10.1002/pro.2085. Epub 2012 May 24. PMID: 22544642

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