Repression of non-essential iron using proteins under iron-limiting conditions by cattle MAP strain: Reporter ion regions (114 - 117 m/z) of peptide tandem mass spectrum from iTRAQ labeled peptides from MAP3698c, MAP3697c and MAP1201c are shown. Quantitation of peptides and inferred proteins are made from relative peak areas of reporter ions. Peptides obtained from cattle MAP cultures grown in iron-replete and iron-limiting medium were labeled with 114 and 115 reporter ions, respectively.. Peptides obtained from sheep MAP cultures grown in iron-replete and iron-limiting medium were labeled with 116 and 117 reporter ions, respectively. The peptide sequences and shown in the parenthesis and the red dashed line illustrates the reporter ion relative peak intensities. Cattle strain of MAP shows an iron sparing response by downregulating expression of iron using proteins.