4MH1:
reference: Crystal structure of L-sorbose dehydrogenase, a pyrroloquinoline quinone-dependent enzyme with homodimeric assembly, from Ketogulonicigenium vulgare., Han X, Xiong X, Jiang D, Chen S, Huang E, Zhang W, Liu X, Biotechnol Lett. 2014 May;36(5):1001-8. doi: 10.1007/s10529-013-1446-5. Epub 2014, Feb 21. PMID: 24557074

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