Fate of labeled hydroxamates during iron transport from hydroxamate-iron chelates

Journal Article · Sat Sep 01 04:00:00 EDT 1973 · J. Bacteriol., v. 115, no. 3, pp. 919-927

OSTI ID:4421986

Arceneaux, J E.L.; Davis, W B; Downer, D N; Haydon, A H; Byers, B R

The fate of the hydroxamic acid-iron transport cofactors during iron uptake from the /sup 59/Fe/sup 3+/ chelates of the /sup 3/H-label ed hydroxamates schizokinen and aerobactin was studied by assay of simultaneous incorporrtion of both /sup 59/Fe/sup 3+/ and /sup 3H/. In the chizokinen-producing organism Bacillus megaterium ATCC 19213 transport of /sup 59/Fe/sup 3+/ from the /sup 3/H- schizokinen-/sup 59/F e/sup 3+/ chelate at 37 C was accompanied by rapid uptake and release (within 2 min) of /sup 3/H-schizokinen, although /sup 3/H-schizokinen discharge was temperature-dependent and did not occur at 0 C. In the schizokinen- requiring strain B. megaterium SK 11 similar release of /sup 3/H-schizokinen occurred only at elevated concentrations of the double-labeled chelate; at lower chelate concentrations, /sup 3/Hschizokinen remained cell-associated. Temperature-dependent uptake of deferri (iron-free) /sup 3/H-schizokinen to levels equivalent to those incorporated from the chelate form was noted in strain SK 11, but strain ATCC 19213 showed only temperature-independent binding of low concentrations of deferri 3H-schizokinen. These results indicate an initial temperature-independent binding of the ferric hydroxamate which is followed rapidly by temperature-dependent transport of the chelate into the cell and an enzyme catalyzed separation of iron from the chelate. The resulting deferri hydroxamate is discharged from the cell only when a characteristic intracellular concentration of the hydroxamate is exceeded, which happens in the schizokinen- requiring strain only at elevated concentrations of the chelate. This strain also appears to draw the deferri hydroxarmate into the cell by a temperature- dependent inechanism. The aerobactin-producing organism Aerobacter aerogenes 62- 1 also demonstrated rapid initial uptake and temperature-dependent discharge of / sup 3/Haerobactin during iron transport from /sup 3/H-aerobactin-/sup 59/Fe/sup 3+/, suggesting a similar ferric hydroxamate transport system in this organism. (auth)

• Research Organization: Univ. of Mississippi, Jackson
• NSA Number: NSA-29-002959
• OSTI ID: 4421986
• Journal Information: J. Bacteriol., v. 115, no. 3, pp. 919-927, Journal Name: J. Bacteriol., v. 115, no. 3, pp. 919-927; ISSN JOBAA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*BACILLUS MEGATHERIUM-- RADIONUCLIDE KINETICS
*IRON 59-- UPTAKE
*TRITIUM-- UPTAKE
CHELATES
CHELATING AGENTS
HYDROXAMIC ACIDS
LABELLED COMPOUNDS
N48740* --Life Sciences--Nuclide Kinetics & Toxicology-- Microorganisms
TRITIUM COMPOUNDS