4HTG:
reference: Insights into the mechanism of pyrrole polymerization catalysed by porphobilinogen deaminase: high-resolution X-ray studies of the Arabidopsis thaliana enzyme., Roberts A, Gill R, Hussey RJ, Mikolajek H, Erskine PT, Cooper JB, Wood SP, Chrystal EJ, Shoolingin-Jordan PM, Acta Crystallogr D Biol Crystallogr. 2013 Mar;69(Pt 3):471-85. doi:, 10.1107/S0907444912052134. Epub 2013 Feb 16. PMID: 23519422

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