scholarly journals Toward a mechanistic understanding of Feo-mediated ferrous iron uptake

Metallomics ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 887-898 ◽  
Author(s):  
Alexandrea E. Sestok ◽  
Richard O. Linkous ◽  
Aaron T. Smith
Keyword(s):  
Ferrous Iron ◽  
Iron Uptake ◽  
Iron Transport ◽  
Structure And Function ◽  
Ferrous Iron Transport ◽  
Mechanistic Understanding ◽  
And Function

The ferrous iron transport (Feo) system is the predominant mode of bacterial Fe2+import. Advancements in the structure and function of FeoB provide glimpses into the mechanism of Fe2+uptake.

scholarly journals Secreted Pyomelanin of Legionella pneumophila Promotes Bacterial Iron Uptake and Growth under Iron-Limiting Conditions

2013 ◽  
Vol 81 (11) ◽  
pp. 4182-4191 ◽  
Author(s):  
Huaixin Zheng ◽  
Christa H. Chatfield ◽  
Mark R. Liles ◽  
Nicholas P. Cianciotto
Keyword(s):  
Legionella Pneumophila ◽  
Ferrous Iron ◽  
Iron Uptake ◽  
Iron Transport ◽  
Ferric Iron ◽  
Iron Acquisition ◽  
Ferric Hydroxide ◽  
Supernatant Fraction ◽  
Content Type ◽  
Ferrous Iron Transport

ABSTRACTIron acquisition is critical to the growth and virulence ofLegionella pneumophila. Previously, we found thatL. pneumophilauses both a ferrisiderophore pathway and ferrous iron transport to obtain iron. We now report that two molecules secreted byL. pneumophila, homogentisic acid (HGA) and its polymerized variant (HGA-melanin, a pyomelanin), are able to directly mediate the reduction of various ferric iron salts. Furthermore, HGA, synthetic HGA-melanin, and HGA-melanin derived from bacterial supernatants enhanced the ability ofL. pneumophilaand other species ofLegionellato take up radiolabeled iron. Enhanced iron uptake was not observed with a ferrous iron transport mutant. Thus, HGA and HGA-melanin mediate ferric iron reduction, with the resulting ferrous iron being available to the bacterium for uptake. Upon further testing ofL. pneumophilaculture supernatants, we found that significant amounts of ferric and ferrous iron were associated with secreted HGA-melanin. Importantly, a pyomelanin-containing fraction obtained from a wild-type culture supernatant was able to stimulate the growth of iron-starved legionellae. That the corresponding supernatant fraction obtained from a nonpigmented mutant culture did not stimulate growth demonstrated that HGA-melanin is able to both promote iron uptake and enhance growth under iron-limiting conditions. Indicative of a complementary role in iron acquisition, HGA-melanin levels were inversely related to the levels of siderophore activity. Compatible with a role in the ecology and pathogenesis ofL. pneumophila, HGA and HGA-melanin were effective at reducing and releasing iron from both insoluble ferric hydroxide and the mammalian iron chelates ferritin and transferrin.

scholarly journals Legionella pneumophila feoAB Promotes Ferrous Iron Uptake and Intracellular Infection

2002 ◽  
Vol 70 (10) ◽  
pp. 5659-5669 ◽  
Author(s):  
Marianne Robey ◽  
Nicholas P. Cianciotto
Keyword(s):  
Yeast Extract ◽  
Legionella Pneumophila ◽  
Ferrous Iron ◽  
Iron Uptake ◽  
Iron Transport ◽  
Growth Defect ◽  
Wild Type ◽  
Extract Agar ◽  
Ferrous Iron Transport ◽  
Yeast Extract Agar

ABSTRACT In order to determine the role of ferrous iron transport in Legionella pathogenesis, we identified and mutated the feoB gene in virulent Legionella pneumophila strain 130b. As it is in Escherichia coli, the L. pneumophila feoB gene was contained within a putative feoAB operon. L. pneumophila feoB insertion mutants exhibited decreased ferrous but not ferric iron uptake compared to the wild type. Growth on standard buffered charcoal yeast extract agar or buffered yeast extract broth was unaffected by the loss of L. pneumophila FeoB. However, the L. pneumophila feoB mutant had a reduced ability to grow on buffered charcoal yeast extract agar with a reduced amount of its usual iron supplementation, a phenotype that could be complemented by the addition of feoB in trans. In unsupplemented buffered yeast extract broth, the feoB mutant also had a growth defect, which was further exacerbated by the addition of the ferrous iron chelator, 2,2′-dipyridyl. The feoB mutant was also 2.5 logs more resistant to streptonigrin than wild-type 130b, confirming its decreased ability to acquire iron during extracellular growth. Decreased replication of the feoB mutant was noted within iron-depleted Hartmannella vermiformis amoebae and human U937 cell macrophages. The reduced intracellular infectivity of the feoB mutant was complemented by the introduction of a plasmid containing feoAB. The L. pneumophila feoB gene conferred a modest growth advantage for the wild type over the mutant in a competition assay within the lungs of A/J mice. Taken together, these results indicate that L. pneumophila FeoB is a ferrous iron transporter that is important for extracellular and intracellular growth, especially in iron-limited environments. These data represent the first evidence for the importance of ferrous iron transport for intracellular replication by a human pathogen.

scholarly journals Ferrous iron transport in Streptococcus mutans.

1986 ◽  
Vol 168 (3) ◽  
pp. 1096-1099 ◽  
Author(s):  
S L Evans ◽  
J E Arceneaux ◽  
B R Byers ◽  
M E Martin ◽  
H Aranha
Keyword(s):  
Streptococcus Mutans ◽  
Ferrous Iron ◽  
Iron Transport ◽  
Ferrous Iron Transport

scholarly journals The soybean NRAMP homologue, GmDMT1, is a symbiotic divalent metal transporter capable of ferrous iron transport

2003 ◽  
Vol 35 (3) ◽  
pp. 295-304 ◽  
Author(s):  
Brent N. Kaiser ◽  
Sophie Moreau ◽  
Joanne Castelli ◽  
Rowena Thomson ◽  
Annie Lambert ◽  
...  
Keyword(s):  
Ferrous Iron ◽  
Iron Transport ◽  
Divalent Metal ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Ferrous Iron Transport

Lactoferrin – 50 years on

2012 ◽  
Vol 90 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Jeremy H. Brock
Keyword(s):  
Gastrointestinal Tract ◽  
Antimicrobial Agent ◽  
Iron Transport ◽  
Iron Absorption ◽  
Structure And Function ◽  
Transport Protein ◽  
Future Research ◽  
Iron Binding ◽  
Plasma Iron ◽  
And Function

It is now some 50 years since iron-binding lactoferrin was first isolated and purified, an event that opened the way to subsequent extensive research on lactoferrin structure and function. The initial recognition that lactoferrin closely resembled the plasma iron-transport protein transferrin meant that lactoferrin was first thought to mediate intestinal iron absorption or to act as an antimicrobial agent. It was also suggested that it could mediate the hyposideraemia of inflammation. This paper will assess to what extent early proposals have stood the test of time and also suggest possible mechanisms by which lactoferrin can mediate the large number of potential functions that have subsequently been proposed. It will also review the ability of lactoferrin to resist digestion in the gastrointestinal tract and identify areas for future research.

scholarly journals Bacterial ferrous iron transport: the Feo system

2015 ◽  
Vol 40 (2) ◽  
pp. 273-298 ◽  
Author(s):  
Cheryl K. Y. Lau ◽  
Karla D. Krewulak ◽  
Hans J. Vogel
Keyword(s):  
Ferrous Iron ◽  
Iron Transport ◽  
Ferrous Iron Transport

scholarly journals Vibrio cholerae FeoA, FeoB, and FeoC Interact To Form a Complex

2016 ◽  
Vol 198 (7) ◽  
pp. 1160-1170 ◽  
Author(s):  
Begoña Stevenson ◽  
Elizabeth E. Wyckoff ◽  
Shelley M. Payne
Keyword(s):  
Complex Formation ◽  
Vibrio Cholerae ◽  
Ferrous Iron ◽  
Iron Transport ◽  
Active Form ◽  
Integral Membrane Protein ◽  
Content Type ◽  
Membrane Complex ◽  
Ferrous Iron Transport

ABSTRACTFeo is the major ferrous iron transport system in prokaryotes. Despite having been discovered over 25 years ago and found to be widely distributed among bacteria, Feo is poorly understood, as its structure and mechanism of iron transport have not been determined. Thefeooperon inVibrio choleraeis made up of three genes, encoding the FeoA, FeoB, and FeoC proteins, which are all required for Feo system function. FeoA and FeoC are both small cytoplasmic proteins, and their function remains unclear. FeoB, which is thought to function as a ferrous iron permease, is a large integral membrane protein made up of an N-terminal GTPase domain and a C-terminal membrane-spanning region. To date, structural studies of FeoB have been carried out using a truncated form of the protein encompassing only the N-terminal GTPase region. In this report, we show that full-length FeoB forms higher-order complexes when cross-linkedin vivoinV. cholerae. Our analysis of these complexes revealed that FeoB can simultaneously associate with both FeoA and FeoC to form a large complex, an observation that has not been reported previously. We demonstrate that interactions between FeoB and FeoA, but not between FeoB and FeoC, are required for complex formation. Additionally, we identify amino acid residues in the GTPase region of FeoB that are required for function of the Feo system and for complex formation. These observations suggest that this large Feo complex may be the active form of Feo that is used for ferrous iron transport.IMPORTANCEThe Feo system is the major route for ferrous iron transport in bacteria. In this work, theVibrio choleraeFeo proteins, FeoA, FeoB, and FeoC, are shown to interact to form a large inner membrane complexin vivo. This is the first report showing an interaction among all three Feo proteins. It is also determined that FeoA, but not FeoC, is required for Feo complex assembly.

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