4P9N:
reference: Structural Insights into the Low-pH Adaptation of a Unique Carboxylesterase from Ferroplasma: Altering the pH Optima of Two Carboxylesterases., Ohara K, Unno H, Oshima Y, Hosoya M, Fujino N, Hirooka K, Takahashi S, Yamashita S, Kusunoki M, Nakayama T, J Biol Chem. 2014 Jul 20. pii: jbc.M113.521856. PMID: 25043762

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