9N2I: GCGR-Gs complex with SRB103Q

cryo-EM structure of GCGR-Gs complex with SRB103Q. Determined by electron microscopy at 3.0 Å resolution. Released 22 Apr 2026.

Method: Electron microscopy
Resolution: 3.0 Å
Organisms: Homo sapiens, Lama glama, synthetic construct
Chains: 6
Atoms: 9,353
Mol. weight: 162.9 kDa
Released: 22 Apr 2026

Explore 9N2I in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9N2I contains 40 α-helices and 59 β-strands across 6 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 9 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	10-37	28
β-strand	40-45	6	5
β-strand	209-214	6	5
β-strand	217-223	7	5
α-helix	235-237	3
β-strand	243-245	3	5
β-strand	248-249	2	6
α-helix	265-278	14
β-strand	286-288	3	5
β-strand	291-292	2	6
α-helix	295-302	8
α-helix	308-311	4
α-helix	313-315	3
α-helix	326-327	2
α-helix	332-351	20
β-strand	359-360	2	5
α-helix	371-390	20

Chain B: 4 helices, 30 β-strands

Element	Residues	Length	Sheet
α-helix	5-25	21
α-helix	30-33	4
α-helix	34-36	3
α-helix	38-39	2
β-strand	47-51	5	7
β-strand	58-63	6	8
β-strand	69-74	6	8
β-strand	78-83	6	8
β-strand	89-94	6	8
β-strand	100-105	6	9
β-strand	111-116	6	9
β-strand	120-125	6	9
β-strand	134-140	7	9
β-strand	146-151	6	10
β-strand	157-161	5	10
β-strand	165-168	4	10
β-strand	178-181	4	10
β-strand	187-192	6	11
β-strand	198-203	6	11
β-strand	207-212	6	11
β-strand	220-222	3	11
β-strand	229-234	6	12
β-strand	240-245	6	12
β-strand	249-254	6	12
β-strand	259-264	6	12
β-strand	273-278	6	13
β-strand	284-289	6	13
β-strand	294-298	5	13
β-strand	303-308	6	13
β-strand	315	1	14
β-strand	319-320	2	7
β-strand	327-330	4	7
β-strand	331	1	14
β-strand	336-339	4	7

Chain G: 4 helices, 0 β-strands

Element	Residues	Length
α-helix	8-21	14
α-helix	30-43	14
α-helix	45-47	3
α-helix	53-55	3

Chain N: 1 helix, 12 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	15
β-strand	11-12	2	16
β-strand	18-25	8	15
β-strand	34-39	6	17
β-strand	45-51	7	17
β-strand	58	1	17
β-strand	68-73	6	15
β-strand	78-83	6	15
α-helix	88-90	3
β-strand	92-98	7	17
β-strand	118	1	17
β-strand	122-124	3	17
β-strand	125-126	2	16

Chain P: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	2-27	26

Chain R: 21 helices, 9 β-strands

Element	Residues	Length	Sheet
α-helix	28-48	21
β-strand	58	1	1
β-strand	61-62	2	2
β-strand	67-68	2	2
β-strand	71	1	1
β-strand	77-80	4	3
α-helix	81-82	2
α-helix	89-91	3
β-strand	95-98	4	3
β-strand	100	1	4
β-strand	106	1	4
α-helix	107-109	3
β-strand	117	1	3
α-helix	122-124	3
α-helix	125-165	41
α-helix	172-203	32
α-helix	205-206	2
α-helix	209-215	7
α-helix	224-253	30
α-helix	264-268	5
α-helix	269-273	5
α-helix	274-288	15
α-helix	301-304	4
α-helix	305-307	3
α-helix	309-334	26
α-helix	348-358	11
α-helix	362-365	4
α-helix	376-397	22
α-helix	398-402	5
α-helix	405-422	18

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Glucagon receptor	R	protein	475	Homo sapiens	P47871 (AlphaFold model)
Guanine nucleotide-binding protein G(s) subunit alpha isoforms short	A	protein	394	Homo sapiens	P63092 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1	B	protein	350	Homo sapiens	P62873 (AlphaFold model)
Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2	G	protein	58	Homo sapiens	P59768 (AlphaFold model)
Nb35	N	protein	128	Lama glama
SRB103Q	P	protein	37	synthetic construct

Sequence of entity 1 (R), FASTA

>9N2I_1 Glucagon receptor (chains R)
MKTIIALSYIFCLVFAAQVMDFLFEKWKLYGDQCHHNLSLLPPPTELVCNRTFDKYSCWP
DTPANTTANISCPWYLPWHHKVQHRFVFKRCGPDGQWVRGPRGQPWRDASQCQMDGEEIE
VQKEVAKMYSSFQVMYTVGYSLSLGALLLALAILGGLSKLHCTRNAIHANLFASFVLKAS
SVLVIDGLLRTRYSQKIGDDLSVSTWLSDGAVAGCRVAAVFMQYGIVANYCWLLVEGLYL
HNLLGLATLPERSFFSLYLGIGWGAPMLFVVPWAVVKCLFENVQCWTSNDNMGFWWILRF
PVFLAILINFFIFVRIVQLLVAKLRARQMHHTDYKFRLAKSTLTLIPLLGVHEVVFAFVT
DEHAQGTLRSAKLFFDLFLSSFQGLLVAVLYCFLNKEVQSELRRRWHRWRLGKVLWEERN
TSNHRASSSPGHGPPSKELQFGRGGGSQDSSAETPLAGGLPRLAESPFDYKDDDD

Sequence of entity 2 (A), FASTA

>9N2I_2 Guanine nucleotide-binding protein G(s) subunit alpha isoforms short (chains A)
MGCLGNSKTEDQRNEEKAQREANKKIEKQLQKDKQVYRATHRLLLLGAGESGKNTIVKQM
RILHVNGFNGEGGEEDPQAARSNSDGEKATKVQDIKNNLKEAIETIVAAMSNLVPPVELA
NPENQFRVDYILSVMNVPDFDFPPEFYEHAKALWEDEGVRACYERSNEYQLIDCAQYFLD
KIDVIKQADYVPSDQDLLRCRVLTSGIFETKFQVDKVNFHMFDVGAQRDERRKWIQCFND
VTAIIFVVASSSYNMVIREDNQTNRLQAALKLFDSIWNNKWLRDTSVILFLNKQDLLAEK
VLAGKSKIEDYFPEFARYTTPEDATPEPGEDPRVTRAKYFIRDEFLRISTASGDGRHYCY
PHFTCAVDTENIRRVFNDCRDIIQRMHLRQYELL

Sequence of entity 3 (B), FASTA

>9N2I_3 Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 (chains B)
MHHHHHHGSSGSELDQLRQEAEQLKNQIRDARKACADATLSQITNNIDPVGRIQMRTRRT
LRGHLAKIYAMHWGTDSRLLVSASQDGKLIIWDSYTTNKVHAIPLRSSWVMTCAYAPSGN
YVACGGLDNICSIYNLKTREGNVRVSRELAGHTGYLSCCRFLDDNQIVTSSGDTTCALWD
IETGQQTTTFTGHTGDVMSLSLAPDTRLFVSGACDASAKLWDVREGMCRQTFTGHESDIN
AICFFPNGNAFATGSDDATCRLFDLRADQELMTYSHDNIICGITSVSFSKSGRLLLAGYD
DFNCNVWDALKADRAGVLAGHDNRVSCLGVTDDGMAVATGSWDSFLKIWN

Sequence of entity 4 (G), FASTA

>9N2I_4 Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2 (chains G)
NTASIAQARKLVEQLKMEANIDRIKVSKAAADLMAYCEAHAKEDPLLTPVPASENPFR

Sequence of entity 5 (N), FASTA

>9N2I_5 Nb35 (chains N)
QVQLQESGGGLVQPGGSLRLSCAASGFTFSNYKMNWVRQAPGKGLEWVSDISQSGASISY
TGSVKGRFTISRDNAKNTLYLQMNSLKPEDTAVYYCARCPAPFTRDCFDVTSTTYAYRGQ
GTQVTVSS

Sequence of entity 6 (P), FASTA

>9N2I_6 SRB103Q (chains P)
HAQGTFTSDYSKYLDAKRAQEFIEWLLAGHHHHHPSW

Primary citation

cryo-EM structure of GCGR-Gs complex with SRB103Q. Zhang, X., Mohebali, N., Belousoff, M.J. et al. To be published.

Other PDB entries of the same protein (UniProt P47871 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3CZF 1.2 Å, Crystal structure of HLA-B*2709 complexed with the glucagon receptor (GR) peptide…
2A83 1.4 Å, Crystal structure of hla-b*2705 complexed with the glucagon receptor (gr) peptide…
9N04 2.3 Å, Cryo-EM structure of GCGR-Gs complex with peptide 15
9N0E 2.3 Å, Cryo-EM structure of GCGR-Gs complex with oxyntomodulin
5EE7 2.5 Å, Crystal structure of the human glucagon receptor (GCGR) in complex with the antagonist…
9XN4 2.53 Å, Glucagon receptor-Gs complex activated by the small molecule agonist SIM1
4ERS 2.64 Å, A Molecular Basis for Negative Regulation of the Glucagon Receptor
8WG8 2.71 Å, Cryo-EM structures of peptide free and Gs-coupled GCGR
4LF3 2.73 Å, Inhibitory Mechanism of an Allosteric Antibody Targeting the Glucagon Receptor
8JIU 2.76 Å, Cryo-EM structure of the GLP-1R/GCGR dual agonist SAR425899-bound human GCGR-Gs complex
8YW5 2.84 Å, Cryo-EM structure of the retatrutide-bound human GCGR-Gs complex
8FU6 2.9 Å, GCGR-Gs complex in the presence of RAMP2

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