The human β2-adrenergic G-protein-coupled receptor
Brian Kobilka, Bill Weis groups (Stanford University), and Ray Stevens,
Peter Kuhn groups (The Scripps Research Institute) and collaborators
Landmark structures of the human
β2-adrenergic G-protein-coupled receptor were determined by
the groups of Brian Kobilka and Bill Weis of Stanford University, and Ray
Stevens and Peter Kuhn of the Scripps Research Institute, resulting in 3
publications in Nature and Science in late 2007, and another paper in
Structure in 2008 (Rasmussen et al., Nature 450, 383-387 (2007); Cherezov et
al., Science 318, 1258-1265 (2007); Rosenbaum et al., Science 318, 1266-1273
(2007); Hanson et al., Structure 16, 897-905 (2008)). This integral membrane
protein which functions in cardiovascular and pulmonary physiology is
activated by adrenaline, and responds to beta blockers. It is a well-studied
member of the G protein-coupled receptor (GPCR) family. The GPCR family
contains almost 1,000 members, who play critical roles in heart disease,
blood pressure regulation, inflammation, and psychological disorders. More
than half of all therapeutic drugs target one GPCR or another. Different
GPCRs respond to a wide array of signals, including light, hormones,
neurotransmitters, proteins, and other signals. Indeed, the only other known
GPCR structure until now was that of rhodopsin, the visual receptor. This was
a challenging project, as GPCRs other than rhodopsin tend to occur in low
natural abundance, have inherent structural flexibility, and suffer
instability in detergent solutions. Extraordinary efforts were undertaken,
including massive screening of crystallization conditions with and without
lipidic cubic phases, and stabilization of protein via Fab binding and by
fusion-protein constructs. Some initial data were collected at the ESRF for
the first paper, but GM/CA-CAT's mini-beam capabilities played a pivotal role
in all of the structure determinations. This project involved a
collaboration with GM/CA staff to enhance the mini-beam capabilities to
improve the user friendliness and robustness of the device. The 5-micron
mini-beam provided high signal-to-background data from the small crystals and
allowed the investigators to overcome radiation damage by "raster collecting"
data along rod-like crystals. Crystals in the lipidic cubic phase could not
be seen visually prompting the development of the diffractive and
fluorescence rastering techniques to locate the crystals. The results
provide insight on GPCR structural plasticity and stability compared to
rhodopsin, they show some modes of ligand binding, and they further
understanding of signal transduction by GPCRs.
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Figure: A comparison of the first
structure of human β2-adrenergic G-protein-coupled receptor
to rhodopsin, from Rasmussen et al. (full citation below) [Figure reprinted
by permission from Macmillan Publishers Ltd:
Nature, 2007]
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Citation:
[1] |
Rasmussen, SGF, Choi, H-J, Rosenbaum, DM, Kobilka, TS, Thian, FS, Edwards,
PC, Burghammer, M, Ratnala, VRP, Sanishvili, R, Fischetti, RF, Schertler,
GFX, Weis, WI, Kobilka, BK. Crystal structure of the human
β2 adrenergic G-protein-coupled receptor, Nature 450, 383-387
(2007). DOI: 10.1038/nature06325. |
[2] |
Cherezov, V, Rosenbaum, DM, Hanson, MA, Rasmussen, SGF, Thian, FS, Kobilka,
TS, Choi, H-J, Kuhn, P, Weis, WI, Kobilka, BK, Stevens, RC.
High-Resolution Crystal Structure of an Engineered Human
β2-Adrenergic G Protein-Coupled Receptor, Science 318,
1258-1265 (2007). DOI: 10.1126/science.1150577. |
[3] |
Rosenbaum, DM, Cherezov, V, Hanson, MA, Rasmussen, SGF, Thian, FS, Kobilka,
TS, Choi, H-J, Yao, X-J, Weis, WI, Stevens, RC, Kobilka, BK. GPCR
Engineering Yields High-Resolution Structural Insights into
β2 Adrenergic Receptor Function, Science 318, 1266-1273
(2007). DOI: 10.1126/science.1150609. |
[4] |
Hanson, MA, Cherezov, V, Griffith, MT, Roth, CB, Jaakola, V-P, Chien, EYT,
Velasquez, J, Kuhn, P, Stevens, RC. A Specific Cholesterol Binding Site
Is Established by the 2.8 Aring; Structure of the Human
β2-Adrenergic Receptor, Structure 16 (6), 897-905 (2008).
DOI: 10.1016/j.str.2008.05.001. |
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