1U6Z:
reference: Origin of exopolyphosphatase processivity: Fusion of an ASKHA phosphotransferase and a cyclic nucleotide phosphodiesterase homolog., Alvarado J, Ghosh A, Janovitz T, Jauregui A, Hasson MS, Sanders DA, Structure. 2006 Aug;14(8):1263-72. PMID: 16905100

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