4FBS:
reference: pH-Dependent Dimerization of Spider Silk N-Terminal Domain Requires Relocation of a Wedged Tryptophan Side Chain., Jaudzems K, Askarieh G, Landreh M, Nordling K, Hedhammar M, Jornvall H, Rising A, Knight SD, Johansson J, J Mol Biol. 2012 Jun 15. PMID: 22706024

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