9ZCJ: Therapeutic antibody with captured antigen

Therapeutic antibody with captured antigen. Determined by X-ray diffraction at 2.6 Å resolution. Released 30 Sept 2026.

Method: X-ray diffraction
Resolution: 2.6 Å
Organism: Homo sapiens
Chains: 6
Atoms: 14,561
Mol. weight: 215.58 kDa
Ligands: MG, NAG
Released: 30 Sept 2026

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

Secondary structure: helices and β-sheets

9ZCJ contains 74 α-helices and 152 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: 25 helices, 32 β-strands

Element	Residues	Length	Sheet
β-strand	226	1	1
β-strand	232-240	9	2
α-helix	247-264	18
α-helix	265-267	3
β-strand	271-278	8	2
β-strand	283-286	4	2
α-helix	291-294	4
α-helix	298-304	7
α-helix	320-334	15
α-helix	342-345	4
β-strand	347-354	8	2
α-helix	365-375	11
α-helix	380-385	6
β-strand	386-393	8	2
α-helix	403-406	4
β-strand	416-419	4	2
α-helix	422-432	11
β-strand	434	1	1
α-helix	454-457	4
β-strand	461-465	5	3
β-strand	467	1	4
β-strand	469	1	4
β-strand	472-476	5	3
β-strand	481-484	4	3
α-helix	486-488	3
β-strand	499-500	2	3
β-strand	502	1	5
β-strand	511	1	5
β-strand	514-520	7	3
α-helix	530-532	3
β-strand	543-547	5	3
β-strand	554	1	6
β-strand	557	1	6
α-helix	559-560	2
β-strand	561	1	7
α-helix	562	1
β-strand	565	1	8
α-helix	566-571	6
α-helix	580-587	8
β-strand	592-598	7	7
α-helix	603	1
β-strand	604-610	7	7
α-helix	612-614	3
α-helix	615-618	4
α-helix	620-624	5
α-helix	635-637	3
β-strand	643-646	4	7
β-strand	662-667	6	7
β-strand	670-680	11	7
β-strand	682	1	9
β-strand	685-687	3	10
β-strand	690-694	5	10
α-helix	696-698	3
α-helix	704-705	2
β-strand	707-711	5	7
α-helix	716-722	7
β-strand	729	1	8

Chain B: 20 helices, 28 β-strands

Element	Residues	Length	Sheet
β-strand	232-240	9	11
α-helix	248-265	18
β-strand	271-278	8	11
β-strand	284-286	3	11
α-helix	296-304	9
α-helix	319-337	19
α-helix	342-346	5
β-strand	347-354	8	11
α-helix	366-374	9
β-strand	386-390	5	11
β-strand	416	1	11
α-helix	422-432	11
α-helix	454-457	4
β-strand	461-465	5	12
β-strand	467	1	13
β-strand	469	1	13
β-strand	472-478	7	12
β-strand	481-484	4	12
α-helix	486-488	3
β-strand	499-504	6	12
β-strand	507-520	14	12
α-helix	530-532	3
β-strand	543-547	5	12
β-strand	554	1	14
β-strand	557	1	14
α-helix	559-560	2
β-strand	561	1	15
α-helix	562	1
β-strand	565	1	16
α-helix	566-571	6
α-helix	580-587	8
β-strand	592-598	7	15
β-strand	604-610	7	15
α-helix	612-619	8
α-helix	620-624	5
α-helix	635-637	3
β-strand	643-646	4	15
α-helix	656-658	3
β-strand	662-667	6	15
β-strand	670-680	11	15
β-strand	682	1	17
β-strand	685-687	3	18
β-strand	690-694	5	18
α-helix	696-698	3
β-strand	707-711	5	15
α-helix	712-715	4
α-helix	716-723	8
β-strand	729	1	16

Chain C: 8 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	5	1	19
β-strand	9-12	4	20
β-strand	17-23	7	19
β-strand	35-39	5	20
β-strand	46-49	4	20
β-strand	50	1	21
β-strand	54	1	21
α-helix	55-56	2
β-strand	63-68	6	19
β-strand	71-77	7	19
α-helix	81-83	3
β-strand	85-93	9	20
β-strand	98-101	4	20
β-strand	105-109	5	20
β-strand	115	1	22
α-helix	116-117	2
β-strand	118-122	5	23
α-helix	123-125	3
α-helix	126-130	5
β-strand	134-143	10	23
β-strand	144	1	22
β-strand	149-154	6	24
β-strand	157-158	2	24
β-strand	163-165	3	23
α-helix	166-168	3
β-strand	169-170	2	23
β-strand	176-184	9	23
α-helix	186-191	6
β-strand	195-201	7	24
β-strand	204-210	7	24
α-helix	212-214	3

Chain D: 8 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	5-8	4	25
α-helix	9	1
β-strand	12-14	3	26
β-strand	20-27	8	25
α-helix	31-33	3
β-strand	36-41	6	26
β-strand	48-54	7	26
β-strand	59-62	4	26
β-strand	71-75	5	25
α-helix	76-78	3
β-strand	80-85	6	25
α-helix	90-92	3
β-strand	94-102	9	26
β-strand	105	1	17
β-strand	113-117	5	26
β-strand	121-125	5	26
α-helix	128-130	3
β-strand	131	1	27
α-helix	132-133	2
β-strand	134-138	5	28
β-strand	149-159	11	28
β-strand	160	1	27
β-strand	165-168	4	29
α-helix	169-171	3
β-strand	177-184	8	28
β-strand	190-199	10	28
α-helix	200-205	6
β-strand	208-214	7	29
β-strand	219-225	7	29

Chain G: 6 helices, 25 β-strands

Element	Residues	Length	Sheet
β-strand	4	1	30
β-strand	5	1	31
β-strand	9-12	4	32
β-strand	18-23	6	31
β-strand	34-39	6	32
β-strand	46-49	4	32
β-strand	50	1	33
β-strand	54	1	33
β-strand	63-68	6	31
β-strand	71-76	6	31
α-helix	81-83	3
β-strand	85-93	9	32
β-strand	98-101	4	32
β-strand	102	1	30
β-strand	105-109	5	32
β-strand	115	1	34
α-helix	116-117	2
β-strand	118-122	5	35
α-helix	126-129	4
β-strand	134-143	10	35
β-strand	144	1	34
β-strand	149-154	6	36
β-strand	158	1	36
β-strand	163-165	3	35
α-helix	166-168	3
β-strand	169-170	2	35
β-strand	176-184	9	35
α-helix	186-190	5
β-strand	195-201	7	36
β-strand	204-210	7	36
α-helix	212-214	3

Chain I: 7 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	5-8	4	37
β-strand	12-14	3	38
β-strand	20-27	8	37
α-helix	31-33	3
β-strand	36-41	6	38
β-strand	48-54	7	38
β-strand	59-62	4	38
β-strand	71-75	5	37
α-helix	76-78	3
β-strand	80-85	6	37
α-helix	90-92	3
β-strand	94-102	9	38
β-strand	105	1	9
β-strand	113-117	5	38
β-strand	121-125	5	38
β-strand	131	1	39
α-helix	132-133	2
β-strand	134-138	5	40
β-strand	149-159	11	40
β-strand	160	1	39
β-strand	165-168	4	41
α-helix	169-171	3
β-strand	173	1	41
β-strand	177-179	3	40
α-helix	180-182	3
β-strand	183-184	2	40
β-strand	190-199	10	40
β-strand	209-214	6	41
α-helix	215-217	3
β-strand	219-224	6	41

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Serine protease complement C2b	A, B	protein	517	Homo sapiens	P06681 (AlphaFold model)
Fab light chain	C, G	protein	216	Homo sapiens
Fab heavy chain	D, I	protein	231	Homo sapiens

Sequence of entity 1 (A, B), FASTA

>9ZCJ_1 Serine protease complement C2b (chains A, B)
KIQIQRSGHLNLYLLLDCSQSVSENDFLIFKESASLMVDRIFSFEINVSVAIITFASEPK
VLMSVLNDNSRDMTEVISSLENANYKDHENGTGTNTYAALNSVYLMMNNQMRLLGMETMA
WQEIRHAIILLTDGKSNMGGSPKTAVDHIREILNINQKRNDYLDIYAIGVGKLDVDWREL
NELGSKKDGERHAFILQDTKALHQVFEHMLDVSKLTDTICGVGNMSANASDQERTPWHVT
IKPKSQETCRGALISDQWVLTAAHCFRDGNDHSLWRVNVGDPKSQWGKEFLIEKAVISPG
FDVFAKKNQGILEFYGDDIALLKLAQKVKMSTHARPICLPCTMEANLALRRPQGSTCRDH
ENELLNKQSVPAHFVALNGSKLNINLKMGVEWTSCAEVVSQEKTMFPNLTDVREVVTDQF
LCSGTQEDESPCKGESGGAVFLERRFRFFQVGLVSWGLYNPCLGSADKNSRKRAPRSKVP
PPRDFHINLFRMQPWLRQHLGDVLNFLPLHHHHHHHH

Sequence of entity 2 (C, G), FASTA

>9ZCJ_2 Fab light chain (chains C, G)
QSVLTQPPSASGTPGQRVTISCSGSRSNVGVNDVKWYQQLPGTAPKLLIYEDNRRPSGVP
DRFSGSKSGTSASLAISGLQSEDEADYYCAAWDDSLAGLIFGGGTKLTVLGQPKANPTVT
LFPPSSEELQANKATLVCLISDFYPGAVTVAWKADGSPVKAGVETTKPSKQSNNKYAASS
YLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS

Sequence of entity 3 (D, I), FASTA

>9ZCJ_3 Fab heavy chain (chains D, I)
EEVQLVQSGAEVKKPGESLKISCKGSGYSFTSYWIGWVRQMPGKGLEWMGIIYPGDSDTR
YSPSFQGQVTISADKSISTAYLQWSSLKASDTAMYYCARRSGLLWFGEPYDAFDIWGQGT
MVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFP
AVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVESKYGPP

Ligands and cofactors

ID	Name	Formula	Copies
MG	Magnesium ion	Mg	2
NAG	2-acetamido-2-deoxy-beta-D-glucopyranose	C8 H15 N O6	1

Water and common crystallization additives (EDO) are not listed.

Primary citation

CSL305: A Dual Functional Therapeutic Antibody Targeting Complement C2 and FcRn. Wymann, S., Morales, R.A.V., Toh, W.H. et al. Int J Mol Sci (2026) 27. DOI 10.3390/ijms27052383 · PubMed

Other PDB entries of the same protein (UniProt P06681 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3ERB 1.8 Å, The Crystal Structure of C2b, a Fragment of Complement Component C2 produced during…
8ACF 1.8 Å, Structure of the argX-117 in complex with a complement C2 fragment at low pH
8ACI 1.85 Å, Structure of ARG-117 Fab in complex with a fragment of complement C2, neutral pH
2I6Q 2.1 Å, Complement component C2a
2I6S 2.7 Å, Complement component C2a
9U60 2.9 Å, C3 convertases zymogen C4b2 in loading state
9U5Z 3.1 Å, C3 convertases zymogen C4b2 in activation state
9U61 3.1 Å, CP/MBL pathways C3 convertase C4b2a and C3 complex
9QJ5 3.5 Å, Structure of the Complement classical and lectin pathway proconvertase, C4b2
9QK2 3.5 Å, Structure of the Complement classical and lectin pathway C3 convertase in complex with…
9QJ4 3.9 Å, Structure of the Complement classical and lectin pathway proconvertase, C4b2
9QPY 4.3 Å, Structure of the Complement classical and lectin pathway C3 convertase

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