Magnetic circular dichroism studies of iron(ii) binding to human calprotectin.

ABSTRACT: Calprotectin (CP) is an abundant metal-chelating protein involved in host defense, and the ability of human CP to bind Fe(ii) in a calcium-dependent manner was recently discovered. In the present study, near-infrared magnetic circular dichroism spectroscopy is employed to investigate the nature of Fe(ii) coordination at the two transition-metal-binding sites of CP that are a His₃Asp motif (site 1) and a His₆ motif (site 2). Upon the addition of sub-stoichiometric Fe(ii), a six-coordinate (6C) Fe(ii) center associated with site 2 is preferentially formed in the presence of excess Ca(ii). This site exhibits an exceptionally large ligand field (10D_q = 11 045 cm^-1) for a non-heme Fe(ii) protein. Analysis of CP variants lacking residues of the

SUBMITTER: Baker TM 

PROVIDER: S-EPMC5361872 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature