5M2I:
reference: Bivalent Llama Single-Domain Antibody Fragments against Tumor Necrosis Factor Have Picomolar Potencies due to Intramolecular Interactions., Beirnaert E, Desmyter A, Spinelli S, Lauwereys M, Aarden L, Dreier T, Loris R, Silence K, Pollet C, Cambillau C, de Haard H, Front Immunol. 2017 Jul 31;8:867. doi: 10.3389/fimmu.2017.00867. eCollection, 2017. PMID: 28824615

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