4I60:
reference: Structural investigation of the interactions of biotinylruthenocene with avidin., Strzelczyk P, Bujacz A, Plazuk D, Zakrzewski J, Bujacz G, Chem Biol Interact. 2013 Jun 25;204(1):6-12. doi: 10.1016/j.cbi.2013.04.005. Epub, 2013 Apr 18. PMID: 23603015

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