Quiz
MO29 GPCRs
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Questions in this quiz (6)
1We can study how GPCR shape changes by a) comparing [blank_start]crystal structures[blank_end] in different ‘frozen’
states across the [blank_start]same[blank_end] GPCR and b) running dynamic [blank_start]computer simulations[blank_end] of GPCRs and
ligand [blank_start]binding[blank_end] events.- Acrystal structures
- Bsame
- Ccomputer simulations
- Dbinding
2GPCRs contain 7 [blank_start]alpha helices[blank_end] and cluster together in [blank_start]different[blank_end] conformations to change the [blank_start]activity[blank_end] of the GPCR. Networks of hydrogen bonds, ionic bonds, and hydrophobic interactions can '[blank_start]pause[blank_end]' the structure dynamics.
- Aalpha helices
- Bdifferent
- Cactivity
- Dpause
3Choose the incorrect statement about ligand binding to GPCRs.
- AAgonist binding stabilises ‘active’ conformations
- BAgonist binding at one side of receptor changes receptor conformation at other end
- CPart of the reason for differences in efficacy and potency between different agonists is stabilisation of a slightly different GPCR conformation
- DInverse agonist binding stabilises ‘inactive’ conformations
- EA stabilised conformation is no longer dynamic
4Choose the best description of an allosteric ligand.
- AA ligand that binds to a different receptor location to the ‘pocket’ that the endogenous agonist binds to
- BA ligand that changes the conformational shape of the GPCR (induced fit)
- CA ligand that binds to the same receptor location that the endogenous agonist binds to
5Order the steps from binding to a GPCR to cellular action being taken.
[blank_start]2[blank_end]. Receptor undergoes conformational change which is transmitted to the cytosolic regions
[blank_start]5[blank_end]. Activated α and β-γ complex bind to and activate target proteins
[blank_start]6[blank_end]. Signalling cascade of downstream targets occurs
[blank_start]3[blank_end]. Trimeric GDP binding protein is activated; α and γ subunits are covalently attached to the phospholipid bilayer, third subunit is β
[blank_start]1[blank_end]. Protein ligand binds
[blank_start]4[blank_end]. α subunit changes shape, exchanges GDP for GTP- A2
- B5
- C6
- D3
- E1
- F4
6Historically when named, GPCRs were thought to couple [blank_start]obly[blank_end] to G proteins. More recently [blank_start]β-arrestin[blank_end] was discovered as able to couple to GPCRs. It has mixed function, it a) solely [blank_start]blocks[blank_end] G protein binding or b) it can [blank_start]facilitate[blank_end] G protein independent signalling pathways.
- Aonly
- Bβ-arrestin
- Cblocks
- Dfacilitate
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- Description
- PHCY211 (Molecules) Quiz on MO29 GPCRs, created by Mer Scott on 15/04/2018.
- Author
- Mer Scott
- Language
- English
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