TABLE 2.

Pyoverdine-mediated iron binding and transport by P. aeruginosa expressing wild-type and mutant FpvA receptors^a

FpvA protein producedb	Amt 59Fe (cpm/A600 [%])c
	Bound	Transported
WT (K1203)	1,183 (133)	7,191 (119)
WT	891 (100)	6,033 (100)
W362A	149 (17)	1,290 (21)
F366Y	918 (103)	7,874 (131)
F369A	716 (80)	7,656 (127)
W391A	579 (65)	4,675 (77)
F795A	315 (35)	2,683 (44)
Y796A	831 (93)	6,304 (104)
Y801A	696 (78)	7,397 (123)

^aP. aeruginosa K2333 (ΔpvdD ΔfpvA) expressing mutant FpvA proteins from chromosome-integrated genes was cultured in CA-supplemented iron-deficient succinate minimal medium, incubated with ⁵⁹Fe-pyoverdine at 0°C (for binding assays) or 37°C (for transport assays), washed, and harvested on filters. Cell-bound ⁵⁹Fe was quantitated with a scintillation counter.

^bThe FpvA proteins carrying the indicated mutations were expressed from genes inserted into the chromosome of P. aeruginosa strain K2333 at the phage D113 attB site, with the exception of the wild-type (WT) FpvA protein produced by strain K1203, which carries the fpvA gene at its usual location.

^cValues are reported as cpm and have been normalized to an A₆₀₀ of 1.0. All values in column 2 have been adjusted for binding (152 cpm ⁵⁹Fe/A₆₀₀), and all values in column 3 have been adjusted for transport (2,840 cpm ⁵⁹Fe/A₆₀₀) by the FpvA⁻ control strain K2333. Numbers in parentheses represent percent binding relative to the strain K2333 expressing wild-type FpvA. Values substantially below those for K2333 expressing wild-type FpvA are indicated in boldfaced type. Data are the means of two experiments.