Teichoic Acid

Question 1

What are teichoic acids?

Answer 1

Negatively charged polyol-phosphate polymers located in the outer cell wall of Gram-positive bacteria

Question 2

In which bacteria are teichoic acids found?

Answer 2

Gram-positive bacteria only

Question 3

Where are teichoic acids located?

Answer 3

They radiate through and out of the peptidoglycan layer

Question 4

What is a polyol?

Answer 4

A linear compound with multiple hydroxyl groups

Question 5

What is the chemical structure of teichoic acid?

Answer 5

Polymer of polyol-phosphate repeat units

Question 6

What roles do teichoic acids provide?

Answer 6

Structure, virulence, adhesion, homeostasis, and defence

Question 7

What are the two types of teichoic acid?

Answer 7

Wall teichoic acid (WTA) and lipoteichoic acid (LTA)

Question 8

How is WTA attached to the cell?

Answer 8

Covalently attached to muramic acid in peptidoglycan

Question 9

How is LTA attached to the cell?

Answer 9

Anchored to the membrane via a lipid

Question 10

Where is WTA polymerised?

Answer 10

Inside the cell before export

Question 11

Where is LTA polymerised?

Answer 11

On the outer face of the membrane

Question 12

What does different glycerol-phosphate stereochemistry suggest?

Answer 12

Convergent evolution of WTA and LTA

Question 13

Why is teichoic acid the first point of host contact?

Answer 13

It forms the outermost layer of Gram-positive bacteria

Question 14

What role does WTA play in growth?

Answer 14

Supports elongation and cell shape

Question 15

What role does LTA play?

Answer 15

Supports cell division

Question 16

What happens if one type of teichoic acid is knocked out?

Answer 16

The other type compensates

Question 17

How do teichoic acids promote adhesion?

Answer 17

Bind host scavenger receptors and wall proteins

Question 18

How do teichoic acids contribute to biofilm formation?

Answer 18

Cleaved teichoic acid acts as sticky matrix

Question 19

How can teichoic acid modify charge?

Answer 19

Addition of D-alanine reduces negative charge

Question 20

Why is charge modification important?

Answer 20

Enables adhesion to negatively charged surfaces

Question 21

How do bacteria attach to neutral surfaces?

Answer 21

Add glucose to enable van der Waals interactions

Question 22

What antimicrobial agents do teichoic acids repel?

Answer 22

Charged antibiotics, CAMPs, and skin lipids

Question 23

How do teichoic acids help immune evasion?

Answer 23

Reduce binding of cationic antimicrobial peptides

Question 24

Why are teichoic acids important for phosphate storage?

Answer 24

They contain large amounts of phosphate

Question 25

What happens in phosphate limitation?

Answer 25

Teichoic acid replaced by teichuronic acid

Question 26

Which ions do teichoic acids attract?

Answer 26

Magnesium and manganese

Question 27

How do teichoic acids protect against freezing?

Answer 27

Prevent ice nucleation by limiting water binding

Question 28

What lipid carrier is used in WTA synthesis?

Answer 28

Polyprenol

Question 29

Which enzyme adds first lipid?

Answer 29

TagO

Question 30

Which enzyme adds second lipid?

Answer 30

TagA

Question 31

Which enzyme forms CDP-glycerol?

Answer 31

TagD

Question 32

Which enzyme primes polymer formation?

Answer 32

TagB

Question 33

Which enzyme elongates polymer?

Answer 33

TagF

Question 34

Which proteins flip WTA across membrane?

Answer 34

TagGH

Question 35

Which enzyme attaches WTA to peptidoglycan?

Answer 35

TagTUV ligase

Question 36

What is synthetic lethality?

Answer 36

Inactivation of two genes causes death, but one alone does not

Question 37

Example in WTA pathway?

Answer 37

TagO knockout viable, TagF knockout lethal

Question 38

How is WTA length controlled?

Answer 38

Polymerase location and substrate availability

Question 39

How are WTA and peptidoglycan synthesis linked?

Answer 39

Shared lipid carrier and co-localised enzymes

Question 40

Why are WTA and PG co-sensitive to antibiotics?

Answer 40

They compete for prenol lipid carrier

Question 41

What carrier is used for LTA synthesis?

Answer 41

Glycerol with two lipid tails

Question 42

What builds LTA polymer?

Answer 42

Phosphatidylglycerol units

Question 43

What immune receptor recognises LTA?

Answer 43

Toll-like receptor 2

Question 44

What roles does LTA play?

Answer 44

Membrane integrity, adhesion, inflammation

Question 45

What is D-alanylation?

Answer 45

Addition of D-alanine to teichoic acids

Question 46

What is the effect of D-alanylation?

Answer 46

Reduces negative charge and increases resistance to AMPs

Question 47

Which bacterium modifies WTA with choline?

Answer 47

Streptococcus pneumoniae

Question 48

Why is choline modification important?

Answer 48

Virulence proteins bind choline residues

Question 49

What is the effect of choline modification?

Answer 49

Increased virulence