10.1021/cb200331g.s001 Trisha M. Hoette Trisha M. Hoette Matthew C. Clifton Matthew C. Clifton Anna M. Zawadzka Anna M. Zawadzka Meg A. Holmes Meg A. Holmes Roland K. Strong Roland K. Strong Kenneth N. Raymond Kenneth N. Raymond Immune Interference in <i>Mycobacterium tuberculosis</i> Intracellular Iron Acquisition through Siderocalin Recognition of Carboxymycobactins American Chemical Society 2016 binding mycobacterial iron acquisition Scn CMB isoforms Mycobacterium tuberculosis Intracellular Iron Acquisition 2016-02-22 11:17:52 Journal contribution https://acs.figshare.com/articles/journal_contribution/Immune_Interference_in_i_Mycobacterium_tuberculosis_i_Intracellular_Iron_Acquisition_through_Siderocalin_Recognition_of_Carboxymycobactins/2570389 The innate immune system antibacterial protein Siderocalin (Scn) binds ferric carboxymycobactin (CMB) and also several catecholate siderophores. Although the recognition of catecholates by Scn has been thoroughly investigated, the binding interactions of Scn with the full spectrum of CMB isoforms have not been studied. Here we show that Scn uses different binding modes for the limited subset of bound CMB isoforms, resulting in a range of binding affinities that are much weaker than other siderophore targets of Scn. Understanding the binding interaction between Scn and CMBs provides clues for the influence of Scn on mycobacterial iron acquisition.