Lec 2 Flashcards
Give the name of the enzyme that catalyses the final reductive step of the FA elongation cycle
enoyl reductase
Describe the enoyl reductase isolated from Brassica napus
tetramer NADH specific Rossman fold @ AS
Describe what was seen when B. napus ENR and BKR were compared Give 2 common amino acids that were seen in the AS and describe their locations
low levels of sequence similarity (around 20%) but high degrees of structural similarity - especially around the AS - both AS contain Lys and Try - Tyr were spatially orientated differently however hydroxyl group were still in the same place ish
Give the catalytic mechanism completed by ENR
What was seen when the ENR structure was solved in E. coli but not in B. napus?
flexible loop/lid region
Name the molecule that inhibits ENR and state how it does this
diazaborine - B makes covalent interactions w/ OH group from the ribose sugar of NADH - stacking interactions also occur - makes contacts w/ the flexible loop and prevents the lid from opening to allow substrate into AS
Why is diazaborine not used in humans?
- B is v toxic - eventually stop all ENRs from working (host ones as well)
Draw the rough structure of Triclosan
How does Triclosan inhibit ENR?
- competitive inhibitor - sits in AS and makes contacts w/ AS residues - makes stacking interactions with NAD ring and its hydroxyl group
Name the mutations that prevents Tri binding to ENR
G93V - however also means that substrate cant fit into AS either - bacteria will either die from Tri binding/have a mutation meaning no catalysis of substrate
Which ENR substrate intermediate does Tri mimic?
the enolate anion
How are Tri compounds being developed that work against parasitic ENR?
Tri linked to esterase compound that allows transport across membranes
M. tuberculosis InhA (just ENR) and E. coli ENR show _____ modification of NAD cofactors by the inhibitor _____
covalent Isoniazid
