3UBP:
reference: A new proposal for urease mechanism based on the crystal structures of the native and inhibited enzyme from Bacillus pasteurii: why urea hydrolysis costs two nickels., Benini S, Rypniewski WR, Wilson KS, Miletti S, Ciurli S, Mangani S, Structure Fold Des 1999 Feb 15;7(2):205-16. PMID: 10368287

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