+Fe conditions). Comprehensive MS and MS2 datasets are provided in the Table of Additional File 3. The concise protein lists in the Tables 1, 2 and 3 are of particular interest in the context of iron homeostasis. Only if protein abundance ratios differed substantially comparing the -Fe vs. +Fe datasets at 26°C and 37°C, the temperature dependency was pointed out in the following paragraphs. Table 1 Abundance differences of Y. pestis proteins profiled in periplasmic fractions of iron-rich vs. iron-starved cells Spot No a) Gene locus b) gene name c) Protein description c) Subc. Loc. d) Fur/RyhB

e) Mascot Score f) exp Mr (Da) exp pI 26°C, Vs (-Fe) g) 26°C, Vs (+Fe) h) 26-ratio -Fe/+Fe i) 26°C P-value j) 37-ratio -Fe/+Fe k) 53 y0028 malE Tozasertib cell line periplasmic maltose-binding protein PP   2150 43937 5.53 0.72 5.98 0.121 0.000 0.760 54 y0137 degQ serine endoprotease PP   1077 55588 6.43 0.39 0.11 2.41 0.0177 0.900 55 y0291 – putative tospovirus resistance protein D U   486 18721 5.44 2.05 0.47 4.320 0.000 N.D. 56 y0541 hmuT hemin-binding periplasmic protein PP Fur 228 27164 5.85 0.46 0.11 4.328 0.000 > 20 57 y0542 hmuS hemin uptake system component U Fur 989 38188 5.56 0.53 0.19 2.780 0.000 2.091 58 y0869 Milciclib mouse cybC cytochrome b(562) PP Fur 626 5035 5.64 0.13 0.03 4.746 N.D. 3.160 59 y0964 frsA fermentation/respiration switch protein U   586 51326 5.98 0.15 0.07 2.208 0.000 1.875 60 y1128 bglX putative AZD1480 beta-glucosidase PP   2324 81506 5.43 3.01 0.52 5.822 0.000 1.740 61 y1189 gltI solute-binding periplasmic protein of glutamate/aspartate ABC transporter PP   2512 35927 7.20 0.41 2.91 0.141 0.005 oxyclozanide N.D. 62 y1223 nrdE ribonucleoside-diphosphate reductase 2, alpha subunit U Fur 198 79914 6.32 0.03 – > 20 N.D. N.D. 63 y1222 nrdF ribonucleoside-diphosphate reductase 2,

beta chain U Fur 561 39335 5.11 0.77 – > 20 N.D. > 20 64 y1430 – putative putative periplasmic iron-binding signal peptide protein U   3359 41211 6.09 – 0.57 < 0.05 N.D. < 0.05 65 y1526 yfuA putative solute-binding protein for iron ABC transporter PP Fur 1979 39620 6.65 2.36 1.46 1.618 0.061 N.D. 66 y1607 hisJ histidine-binding periplasmic protein of high-affinity histidine transport system PP   1494 31529 5.01 0.29 0.93 0.309 0.000 0.350 67 y1744 - hypothetical protein y1744 CY   324 5183 5.92 0.38 - > 20 N.D. 4.510 68 y1897 yfeA periplasmic-binding protein for iron and manganese ABC transporter CM Fur 1201 31395 5.80 2.87 0.63 4.576 0.000 4.780 69 y1936 sufC iron-sulfur cluster assembly protein SufC, ATPase component ML Fur 726 28460 5.10 0.16 0.02 7.514 0.000 > 20 70 y1937 sufD cysteine desulfurase activator complex subunit SufD U Fur 369 60476 6.76 0.06 – > 20 N.D.