FREE IRON IN PSEUDOMONAS PUTIDA KT2440 MUTANTS LACKING BACTERIOFERRITIN COMPONENT PROTEINS

摘要

Soil bacteria such as Pseudomonas putida contribute to nutrient cycling within the soil surrounding plant roots. These bacteria have been found beneficial to plants, colonizing the tips of plant roots to feed upon sheaved plant cells and, in turn, enhancing plant growth and restricting the growth of plant pathogens. Particularly interesting is the uptake of iron by P. putida, which produces pyoverdine as a siderophore, but has membrane receptors for many exogenous siderophores. Iron received by bacteria is utilized by metalloenzymes, transported intracellularly by chaperone proteins or is stored as a biomineral within ferritin-like macromolecules. P. putida store iron in bacterioferritins (bfr) and are thought also to be a part of the reactive oxygen defense mechanism. Living P. putida would have access to iron from both soil minerals or else the iron-containing remnants of proximal dead microbes. It is not known from which iron pool bacteria would have a great intake: exogenous bacterioferritin or iron-containing soil minerals.