Mycobacterium tuberculosis Flashcards
(22 cards)
Which proteins, secreted by the ESX1 T5SS, have WXG motifs and work together as a dimer
ESAT-6 AND CFP10
Which proteins for lipid transport are amplified in the Mtb genome
Mmpt gene family
How are Truncated haemoglobins in Mtb modified?
Glycosylation
A catalase-periodoxase enzyme that degrades hydrogen peroxide (ROS) to water and oxygen
KatG
Superoxide dimutase enzymes that degrade superoxide produced by IFN-gamma stimulated macrophages
SodA and SodC
A reduced sulphur-containing compound that keeps the bacterial cytoplasm reduced when pH is low outside and there is oxidative stress from ROS
Mycothiol
NADH-dependent peroxidase and peroxinitrate reductase
Degrades reactive oxygen and nitrogen species
How does TrHbN overexpression interfere with host immunology
Suppressing CD80 and CD86 (interferes with T-cell activation by the macrophage)
What is the result of glycosylated HbN surface expression
Optimal nitric oxide dioxygenase (NOD) function
What are the two roles of truncated haemoglobins in Mtb
Detoxifying RNS and interfering with host immunology
Which proteins in Mtb’s membrane are key for acid resistance
OmpATb proteins
Which secretion systems mediate the rupture of phagosomal membranes inside host phagocytes
ESX-1
Which secretion system is required for Mtb’s ability to move from the alveolar space into the lung interstitium
ESX-1
Which secretion system secretes PE and PPE proteins including PE proteins with lipase domains to degrade host enzymes
ESX-5
Which genes lie adjacent to PE-PPE genes in the same operon
ESX and ESAT-6
What does 9% of the Mtb genome consist of
polymorphic tandemly repeated PE and PPE glycine-rich sequences
Why do PE and PPE encoded antigens show high variation
Due to intragenic recombination and replication slippage due to their repeated sequences
How do PE and PPE proteins give further antigenic variation
They dimerize on cell surfaces
Mtb’s genome is GC-rich (65.6%), so which amino acids are rarely found in proteins?
Asparagine, Isoleucine, Phenylalanine, Lysine and Tyrosine (NIFKY)
An lateral transfer of which genes caused Mtb to become pathogenic?
A PE-PPE gene pair into an ESAT gene cluster in a soil ancestor of mycobacterium
What is current triple therapy for Mtb?
Isoniazid - inhibits mycolic acid synthesis
Flouroquinolones - affects DNA gyrase
Rifampicin - inhibits RNA polymerase
- Course is 6 months long
What new drugs have been developed for Mtb?
- Delmanid - inhibits mycolic acid synthesis
- Pretomanid - causes nitric oxide synthesis and inhibits mycolic acid synthesis
- Bedaqualine - inhibits ATP synthesis by binding ATP synthase (fat-soluble)
