Abstract
Cyanobacteria require large quantities of iron to maintain their photosynthetic machinery; however, in most environments iron is present in the form of insoluble iron oxides. Whether cyanobacteria can utilize these sources of iron, and the potential molecular mechanisms involved remains to be defined. There is increasing evidence that pili can facilitate electron donation to extracellular electron acceptors, like iron oxides in non-photosynthetic bacteria. In these organisms, the donation of electrons to iron oxides is thought to be crucial for maintaining respiration in the absence of oxygen. Our study investigates if PilA1 (major pilin protein) may also provide a mechanism to convert insoluble ferric iron into soluble ferrous iron. Growth experiments supported by spectroscopic data of a strain deficient in pilA1 indicate that the presence of the pilA1 gene enhances the ability to grow on iron oxides. These observations suggest a novel function of PilA1 in cyanobacterial iron acquisition.
Highlights
In the oxidative environment of Earth, organisms must contend with the problem of accessing essential elements, which are locked into insoluble oxides
Iron acquisition in bacteria Given the limited bioavailability of iron, several acquisition strategies have evolved in bacteria
Electron donation to iron oxides as a mechanism for utilizing otherwise inaccessible sources of iron has recently been suggested to occur in cyanobacteria [14]
Summary
In the oxidative environment of Earth, organisms must contend with the problem of accessing essential elements, which are locked into insoluble oxides. Siderophore-mediated iron uptake is one such strategy, involving the synthesis and secretion of low-molecular-weight iron chelators that tightly bind Fe3+. This results in a ferrisiderophore complex that is transported as a whole into the cell where the iron can be removed for cellular utilization. This form of siderophore-mediated iron uptake has been studied extensively in Gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa [2,3,4,5]. The uptake of heme through hemophores (proteins that are synthesized and excreted) is another iron-acquisition strategy that has only been found in Gram-negative bacteria [6,7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
