5EKU:
reference: A glutamate/aspartate switch controls product specificity in a protein arginine methyltransferase., Debler EW, Jain K, Warmack RA, Feng Y, Clarke SG, Blobel G, Stavropoulos P, Proc Natl Acad Sci U S A. 2016 Feb 23;113(8):2068-73. doi:, 10.1073/pnas.1525783113. Epub 2016 Feb 8. PMID: 26858449

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).