1PYM:
reference: Helix swapping between two alpha/beta barrels: crystal structure of phosphoenolpyruvate mutase with bound Mg(2+)-oxalate., Huang K, Li Z, Jia Y, Dunaway-Mariano D, Herzberg O, Structure Fold Des 1999 May;7(5):539-48. PMID: 10378273

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