VL15: The battle for iron Flashcards
What variants of iron are relevant for human and bacterial life?
¨Ferrous iron: Fe2+ and
Ferric iron: Fe3+ (always in complex with prot or molecules Iron-sulphur cluster, ferritin, cytochrom, oxyhemoglobin)
Fe2+-> oxidation -> Fe3+ -> reduction -> Fe2
Fe2O3 = rust
What do bacteria need iron for?
part of different molecules
- -heme in cytochromes (responsible for generation of protein motive force using electron transport chain)
- cytochromes transfer electrons + pump out H+ ions -> they come back in through ATP synthase -> ATP
-heme in hemoglobin: oxygen transport of red blood cells
- Fe-S clusters:
- cofactor for many proteins
- Electron transfer: FeS clusters can access various redox states
- Redox catalysis: low redox potential
- non redox catalysis:
- gene expression regulation, reversible cluster makes good sensors for redox/iron related stresses - Metalloproteins
- some prot that directly bind one or 2 iron molecules:
- Ribonucleotide reductase (ribonucleotides -> desoxyribonucleotides for DNA repair)
- Methane monooxygenase: found in methanotrophs
Where is the rion in humans?/
Which iron storage forms exist in humans?
and what do they do?
2,5 g hemoglobin (in red blood cells)
2g ferritin (mostly bone maarrow, liver, spleen) iron reserve
400 mg myoglobin (storing oxygen), cytochromes (redox reactions ->ATP)
3-4 mv transferrin (circulates through plsma bound to ferritin)
> 90% iron intracellular
free soluble Fe2 raptily bound by circulating transferrin (in healthy humans: 30-40% saturated
haptoglobin binds hemoglobin released from red blood cells
hemopexin highest affinity for heme, grabs what it can find
Is iron important for pathogenesis and virulence?
kjh
How do bacteria acquire iron?
kjh
How is bacterial iron axquisition regulated?
kjh
Exploiting the need for iron- a possible vaccine target?
kjb
What is the oxidation reaction of irond?
kjh
How gets iron inserted into heme?
kjh
3 examples of where FeS clusters are used
FeS are involved in a lot of important processes
Why are FeS clusters important? What happens if 1 Fe gets lost from the cluster?
kjh
What is nutritional immunityy?
The concept that host immunity to bacterial infection can be achieved by restricting the availability of free iron.
What is the fenton reaction?
Fe2+ + H2O2 -> Fe3+ + .OH + OH-
Fe3+ + H2O2 -> Fe2+ + .OOH + H+
Ferrous iron (2+) is oxidized by hydrogen peroxide to ferric iron (3+)+ hydroxyl radical + hydroxyl anion,ferric iron can be reduced back to to ferrous iron, producing superoxide radical +proton
superoxide is very good oxidant, rapidly destabiliyes FeS clusters (even better than H2O2), thereby releasing more H2O2 which will produce even more superoxide if not stopped
What happens with free iron? How is it toxic?
kjh
What happens when you have too much iron?
kjn
ich hab bis 4. aufgepasst
pyoverdin merken kommt später nochmal
