1NZI: Complement C1s component

Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s. Determined by X-ray diffraction at 1.5 Å resolution. Released 10 Jun 2003.

Method: X-ray diffraction
Resolution: 1.5 Å
Organism: Homo sapiens
Chains: 2
Atoms: 2,809
Mol. weight: 36.42 kDa
Ligands: MG, CA
Released: 10 Jun 2003

Explore 1NZI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1NZI contains 4 α-helices and 26 β-strands across 2 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: 2 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	5-9	5	1
α-helix	16-18	3
β-strand	21-28	8	2
β-strand	33-43	11	1
α-helix	48-50	3
β-strand	54-58	5	2
β-strand	65-67	3	2
β-strand	70-71	2	1
β-strand	82-86	5	1
β-strand	90-97	8	2
β-strand	107-116	10	1
β-strand	131-135	5	3
β-strand	138-142	5	3
β-strand	148-149	2	4
β-strand	156-157	2	4

Chain B: 2 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	5-9	5	5
α-helix	16-18	3
β-strand	21-28	8	6
β-strand	33-44	12	5
α-helix	48-50	3
β-strand	54-58	5	6
β-strand	63-67	5	6
β-strand	69-71	3	5
β-strand	82-86	5	5
β-strand	90-97	8	6
β-strand	107-116	10	5
β-strand	131-135	5	7
β-strand	138-142	5	7
β-strand	148-149	2	8
β-strand	156-157	2	8

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Complement C1s component	A, B	protein	159	Homo sapiens	P09871 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>1NZI_1 Complement C1s component (chains A, B)
EPTMYGEILSPNYPQAYPSEVEKSWDIEVPEGYGIHLYFTHLDIELSENCAYDSVQIISG
DTEEGRLCGQRSSNNPHSPIVEEFQVPYNKLQVIFKSDFSNEERFTGFAAYYVATDINEC
TDFVDVPCSHFCNNFIGGYFCSCPPEYFLHDDMKNCGVN

Ligands and cofactors

ID	Name	Formula	Copies
MG	Magnesium ion	Mg	2
CA	Calcium ion	Ca	2

Primary citation

X-ray structure of the Ca2+-binding interaction domain of C1s. Insights into the assembly of the C1 complex of complement. Gregory, L.A., Thielens, N.M., Arlaud, G.J. et al. J Biol Chem (2003) 278:32157-32164. DOI 10.1074/jbc.M305175200 · PubMed

Other PDB entries of the same protein (UniProt P09871 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1ELV 1.7 Å, Crystal structure of the catalytic domain of human complement C1S protease
8TYP 1.8 Å, Complement Protease C1s Inhibited by 6-(4-phenylpiperazin-1-yl)pyridine-3-carboximidamide
4LOS 2.0 Å, C1s CUB2-CCP1
4LOR 2.5 Å, C1s CUB1-EGF-CUB2 in complex with a collagen-like peptide from C1q
5UBM 2.5 Å, Crystal structure of human C1s in complex with inhibitor gigastasin
8GMN 2.6 Å, Crystal structure of human C1s in complex with inhibitor
9X1H 2.6 Å, Cryo-EM Structure of human complement C1s CUB domain in complex with RAY121
4J1Y 2.66 Å, The X-ray crystal structure of human complement protease C1s zymogen
4LOT 2.92 Å, C1s CUB2-CCP1-CCP2
4LMF 2.92 Å, C1s CUB1-egf-CUB2
8W18 3.94 Å, The crystal structure of the Michaelis-Menten complex of a C1s/C1-INH at 3.94 Angstroms
6F1C 4.2 Å, C1rC1s complex

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