Metal Acquisition- Lecture 18

Question 1

Heme

Answer 1

Binds fe2+

Question 2

Hemoglobin

Answer 2

Binds heme

Question 3

Hemopexin and haptoglobin

Answer 3

binds heme when erythrocytes have been lysed

Question 4

Ferritin

Answer 4

Binds Fe3+ intracellularly

Question 5

Transferrin

Answer 5

Fe3+ binding protein in serum

Question 6

NRAMP 1

Answer 6

localizes the phagosomal membranes, pumps Mn and Fe2+ out of the phagosome, sequesters nutrients away from pathogens

Question 7

Lactoferrin

Answer 7

Binds Fe3+ in breast milk, tears and Saliva

Question 8

Hemophores

Answer 8

Binds heme or heme-binding proteins, found in gram-negative and gram-positive bacteria

Question 9

HmuR

Answer 9

an example of a Ton-B dependent transporter for heme or heme-binding proteins , found in gram-negative bacteria

Question 10

Which bacteria can sequester transferrin?

Answer 10

Corynebacteria diphtheria, has lipoprotein transporters for heme, HtaA and HtaB

Question 11

Which bacteria has transferrin-binding proteins

Answer 11

Neisseria, Haemophilus influenza, moraxella catarrhalid

Question 12

Transferrin-binding proteins

Answer 12

TbpA/TbpB, Ton-B dependent receptors that bind iron 3+

Question 13

Lactoferrin receptors

Answer 13

Found in Neisseria, Treponema palladium, H. pylori and Streptococcus pneumonia

Question 14

Red Queen Hypothesis

Answer 14

Transferrin variant Ser589, confers immunity to transferrin-binding protein A of H. influenza
Genetic heterogeneity of transferrin among hominids displays natural selection

Question 15

Siderophores

Answer 15

Fe3+ binding proteins, high-affinity outcompetes transferrin, ex: Enterobactin produced by Enterobacteriaeae

Question 16

Transport of siderophores in bacteria

Answer 16

Gram negative: use Ton-B dependent OM transporters, and ABC transporters at IM
Gram- positive: use diffusion across PG, then ABC transporters

Question 17

Lipocalin/Siderocalin

Answer 17

Part of the innate immune system, binds and sequesters siderophores

Question 18

Chelating subunit of siderophores

Answer 18

1,2-dihydroxybenzoyl subunits

Question 19

Strategies to evade Lipocalin siderophore sequestering

Answer 19

Glycosylation or use of 3,4-dihydroxy benzoyl subunits, prevents lactoferrin from binding

Question 20

Nissle 1917

Answer 20

Salmochelin-producing bacteria, E. coli, probiotic found solider immune to diarhea causing bacterial pathogen
Reduces Salmonella colonization in mouse models of acute colitis

Question 21

Siderophore vaccination

Answer 21

Reduces salmonella colonization and leads to expansion of gut commensals
Add chemical conjugates to siderophores

Question 22

Psoriasin

Answer 22

Secreted by keratinocytes, inhibits microbial growth through chelation of Zn2+

Question 23

Calprotectin

Answer 23

Dual-binding properties for Mn2+ and Zn2+, contain Calgranulin A and B subunits which form S1 and S2 binding sites. S1 can bind both Mn and Zn, through six histidine residues, and S2 binds only Zn through 3 histidine residues and 1 aspartate residue.

Question 24

Results from liver abscesses of mice infected with S. Aureus

Answer 24

Calprotectin sequesters zinc and manganese in abscesses

Question 25

What effect does Calprotectin have on biofilm formation

Answer 25

Promotes biofilm formation since is disrupts the LPS synthesis pathway in H. pylori

Question 26

Znu

Answer 26

Ton-B dependent zinc uptake system, uses ABC transporters at IM

Question 27

Zinc Acquisition in yersina pseudotuberculosis

Answer 27

Uses both T6SS and Znu, secretes, T6SS secretes zinc binding proteins

Question 28

Yersiniabactin

Answer 28

Zinc-siderophore found in yersinia pests, binds zinc and transports using YbtX IM transporter

Question 29

Calprotectin-binding protein A

Answer 29

CpbA extracts Zn from calprotectin in a TonB-dependent manner, found in Neisseria meningitides

Question 30

Systems for manganese acquisition

Answer 30

Found in all bacteria
(1): Mn2+ importers at the inner membrane, Manganese can diffuse into both positive or negative bacteria
(2): SitABC system, consists of substrate-binding sit protein, and ABC transporter, can also bind Fe3+ with low affinity