3UPU:
reference: The T4 Phage SF1B Helicase Dda Is Structurally Optimized to Perform DNA Strand Separation., He X, Byrd AK, Yun MK, Pemble CW 4th, Harrison D, Yeruva L, Dahl C, Kreuzer KN, Raney KD, White SW, Structure. 2012 May 30. PMID: 22658750

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