8W18: Michaelis-Menten complex of a C1s/C1-INH

The crystal structure of the Michaelis-Menten complex of a C1s/C1-INH at 3.94 Angstroms. Determined by X-ray diffraction at 3.94 Å resolution. Released 26 Jun 2024.

Method: X-ray diffraction
Resolution: 3.94 Å
Organism: Homo sapiens
Chains: 3
Atoms: 6,029
Mol. weight: 88.25 kDa
Released: 26 Jun 2024

Explore 8W18 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

8W18 contains 32 α-helices and 64 β-strands across 3 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: 7 helices, 22 β-strands

Element	Residues	Length	Sheet
α-helix	292-293	2
β-strand	294	1	10
α-helix	295	1
β-strand	302-304	3	11
β-strand	311	1	10
α-helix	312	1
β-strand	316-321	6	11
β-strand	325-326	2	12
β-strand	327-328	2	13
β-strand	333-334	2	13
β-strand	336-340	5	11
β-strand	341	1	14
β-strand	347	1	14
β-strand	355-356	2	12
α-helix	357	1
β-strand	358	1	15
α-helix	362-364	3
β-strand	369-370	2	16
β-strand	377	1	15
β-strand	381-382	2	17
β-strand	384-385	2	16
β-strand	391	1	18
β-strand	401-403	3	17
β-strand	409-410	2	17
β-strand	411	1	19
β-strand	415	1	19
α-helix	417-419	3
β-strand	423	1	18
α-helix	431-433	3

Chain B: 7 helices, 22 β-strands

Element	Residues	Length	Sheet
β-strand	439	1	6
β-strand	442-443	2	4
β-strand	452-455	4	7
β-strand	458-459	2	5
β-strand	460-464	5	7
β-strand	469-472	4	7
β-strand	485-487	3	7
β-strand	491	1	8
α-helix	494-497	4
β-strand	501-503	3	7
β-strand	505-510	6	7
β-strand	531-535	5	7
α-helix	547-548	2
β-strand	549	1	4
β-strand	564-569	6	4
β-strand	581	1	8
β-strand	583-588	6	4
β-strand	589-590	2	9
α-helix	592-594	3
α-helix	610-612	3
β-strand	616-617	2	4
β-strand	618-619	2	9
α-helix	622-624	3
β-strand	626	1	6
β-strand	635-639	5	4
β-strand	647-655	9	4
β-strand	664-667	4	4
α-helix	669-671	3
α-helix	672-681	10

Chain I: 18 helices, 20 β-strands

Element	Residues	Length	Sheet
α-helix	124-131	8
α-helix	132-137	6
α-helix	139-158	20
β-strand	167-169	3	1
α-helix	171-182	12
α-helix	188-196	9
α-helix	199-200	2
α-helix	206-212	7
β-strand	218-226	9	2
α-helix	231-233	3
α-helix	234-243	10
α-helix	247-248	2
β-strand	249-250	2	2
α-helix	251	1
α-helix	255-269	15
β-strand	287-295	9	2
β-strand	299-301	3	3
α-helix	302-304	3
α-helix	305-307	3
β-strand	309-315	7	1
β-strand	318-337	20	1
β-strand	342-348	7	1
β-strand	349	1	3
β-strand	353-360	8	1
α-helix	367-372	6
α-helix	376-386	11
α-helix	390-391	2
β-strand	392-399	8	1
β-strand	401-408	8	2
α-helix	409-415	7
β-strand	440-449	10	2
β-strand	453-455	3	3
β-strand	465	1	4
β-strand	468-469	2	5
β-strand	470-472	3	1
β-strand	477-483	7	1
β-strand	488-489	2	1
β-strand	492-495	4	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Plasma protease C1 inhibitor	I	protein	395	Homo sapiens	P05155 (AlphaFold model)
Complement C1s subcomponent light chain	B	protein	251	Homo sapiens	P09871 (AlphaFold model)
Complement C1s subcomponent heavy chain	A	protein	151	Homo sapiens	P09871 (AlphaFold model)

Sequence of entity 1 (I), FASTA

>8W18_1 Plasma protease C1 inhibitor (chains I)
GSTGSTDSPTQPTTGSFCPGPVTLCSDLESHSTEAVLGDALVDFSLKLYHAFSAMKKVET
NMAFSPFSIASLLTQVLLGAGENTKTNLESILSYPKDFTCVHQALKGFTTKGVTSVSQIF
HSPDLAIRDTFVNASRTLYSSSPRVLSNNSDANLELINTWVAKNTNNKISRLLDSLPSDT
RLVLLNAIYLSAKWKTTFDPKKTRMEPFHFKNSVIKVPMMNSKKYPVAHFIDQTLKAKVG
QLQLSHNLSLVILVPQNLKHRLEDMEQALSPSVFKAIMEKLEMSKFQPTLLTLPRIKVTT
SQDMLSIMEKLEFFDFSYDLNLCGLTEDPDLQVSAMQHQTVLELTETGVEAAAASAISVA
RTLLVFEVQQPFLFVLWDQQHKFPVFMGRVYDPRA

Sequence of entity 2 (B), FASTA

>8W18_2 Complement C1s subcomponent light chain (chains B)
IIGGSDADIKNFPWQVFFDNPWAGGALINEYWVLTAAHVVEGNREPTMYVGSTSVQTSRL
AKSKMLTPEHVFIHPGWKLLEVPEGRTNFDNDIALVRLKDPVKMGPTVSPICLPGTSSDY
NLMDGDLGLISGWGRTEKRDRAVRLKAARLPVAPLRKCKEVKVEKPTADAEAYVFTPNMI
CAGGEKGMDSCKGDAGGAFAVQDPNDKTKFYAAGLVSWGPQCGTYGLYTRVKNYVDWIMK
TMQENSTPRED

Sequence of entity 3 (A), FASTA

>8W18_3 Complement C1s subcomponent heavy chain (chains A)
GSTGSMPCPKEDTPNSVWEPAKAKYVFRDVVQITCLDGFEVVEGRVGATSFYSTCQSNGK
WSNSKLKCQPVDCGIPESIENGKVEDPESTLFGSVIRYTCEEPYYYMENGGGGEYHCAGN
GSWVNEVLGPELPKCVPVCGVPREPFEEKQR

Primary citation

The Crystal Structure of the Michaelis-Menten Complex of C1 Esterase Inhibitor and C1s Reveals Novel Insights into Complement Regulation. Garrigues, R.J., Garrison, M.P., Garcia, B.L. J Immunol (2024) 213:718-729. DOI 10.4049/jimmunol.2400194 · PubMed

Other PDB entries of the same protein (UniProt P05155 (AlphaFold model), which also has an AlphaFold model), best resolution first:

5DU3 2.1 Å, Active form of human C1-inhibitor
2OAY 2.35 Å, Crystal structure of latent human C1-inhibitor
5DUQ 2.9 Å, Active human c1-inhibitor in complex with dextran sulfate
7AKV 3.6 Å, The cryo-EM structure of the Vag8-C1 inhibitor complex

Browse structure collections

About this viewer

MolViewer shows 8W18 directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.