4IL8:
reference: Identification of an essential active-site residue in the alpha-D-phosphohexomutase enzyme superfamily., Lee Y, Mehra-Chaudhary R, Furdui C, Beamer LJ, FEBS J. 2013 Jun;280(11):2622-32. doi: 10.1111/febs.12249. Epub 2013 Apr 8. PMID: 23517223

This OCA Structure page
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