Week 6 Bollough Lecture 15 Flashcards
1
Q
What is Bacteriorhodopsin?
A
bR is a 248 amino acid protein found in a halophilic bacterium that lives in brine lakes- Halobacterium salinarum.
a) bR converts sunlight into chemical energy by generating a transmembrane proton gradient.
b) the proton gradient is used to drive an ATP synthase
2
Q
Why is bacteriorhodopsin coloured?
A
The purple colour comes from a covalently attached chromophore- retinal, bound through a Schiff base linkage to Lys216
a) The ε-amino group of lys216 is
protonated
b) Retinal absorbs light and isomerizes from all-trans to 13-cis
3
Q
What is the structure of bacteriorhodopsin?
A
7 transmembrane helices named a – g, which form a bundle
a) The 216lys retinal is bound to the middle of the structure
b) In the middle there is a pore
