Absence of arsenate in DNA from arsenate-grown GFAJ-1 cells

摘要

A strain of Halomonas bacteria, GFAJ-1, has been reported to be able to usearsenate as a nutrient when phosphate is limiting, and to specificallyincorporate arsenic into its DNA in place of phosphorus. However, we have foundthat arsenate does not contribute to growth of GFAJ-1 when phosphate islimiting and that DNA purified from cells grown with limiting phosphate andabundant arsenate does not exhibit the spontaneous hydrolysis expected ofarsenate ester bonds. Furthermore, mass spectrometry showed that this DNAcontains only trace amounts of free arsenate and no detectable covalently boundarsenate.