3IU3: Fab fragment of therapeutic antibody Basiliximab

Crystal structure of the Fab fragment of therapeutic antibody Basiliximab in complex with IL-2Ra (CD25) ectodomain. Determined by X-ray diffraction at 2.9 Å resolution. Released 26 Jan 2010.

Method: X-ray diffraction
Resolution: 2.9 Å
Organisms: Mus musculus, Homo sapiens
Chains: 9
Atoms: 12,566
Mol. weight: 216.01 kDa
Released: 26 Jan 2010

Explore 3IU3 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

3IU3 contains 54 α-helices and 174 β-strands across 9 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, 23 β-strands

Element	Residues	Length	Sheet
β-strand	2-4	3	1
β-strand	8-10	3	2
β-strand	16-22	7	1
α-helix	27-29	3
β-strand	32-37	6	2
β-strand	43-50	8	2
β-strand	55-58	4	2
α-helix	60-62	3
β-strand	66-71	6	1
β-strand	76-81	6	1
α-helix	86-88	3
β-strand	90-97	8	2
β-strand	102-105	4	2
β-strand	109-113	5	2
β-strand	119	1	3
α-helix	120-121	2
β-strand	122-126	5	4
β-strand	133-134	2	4
β-strand	137-147	11	4
β-strand	148	1	3
β-strand	153-156	4	5
β-strand	161	1	5
β-strand	165-167	3	4
α-helix	168-170	3
β-strand	171-172	2	4
β-strand	178-187	10	4
α-helix	190-193	4
β-strand	196-202	7	5
α-helix	203-205	3
β-strand	207-213	7	5

Chain B: 8 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	6
β-strand	10-13	4	7
β-strand	19-29	11	6
β-strand	33-37	5	7
β-strand	44-48	5	7
β-strand	52-53	2	7
α-helix	54	1
β-strand	61-74	14	6
α-helix	79-81	3
β-strand	83-88	6	7
β-strand	95	1	7
β-strand	99-103	5	7
β-strand	108	1	8
α-helix	109-110	2
β-strand	111-115	5	9
α-helix	116-118	3
α-helix	119-124	6
β-strand	126-136	11	9
β-strand	137	1	8
β-strand	141-147	7	10
β-strand	150-152	3	10
β-strand	156-160	5	9
α-helix	161-164	4
β-strand	170-179	10	9
α-helix	180-184	5
β-strand	188-195	8	10
α-helix	201	1
β-strand	202-207	6	10

Chain C: 10 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	2-4	3	11
α-helix	5-7	3
β-strand	8-10	3	12
β-strand	16-22	7	11
α-helix	27-29	3
β-strand	31-37	7	12
β-strand	43-50	8	12
β-strand	55-58	4	12
α-helix	60-62	3
β-strand	66-71	6	11
β-strand	76-81	6	11
α-helix	86-88	3
β-strand	90-97	8	12
β-strand	104-105	2	12
β-strand	109-113	5	12
β-strand	119	1	13
α-helix	120-121	2
β-strand	122-126	5	14
α-helix	130-132	3
β-strand	133-134	2	14
β-strand	137-147	11	14
β-strand	148	1	13
β-strand	153-156	4	15
α-helix	157-159	3
β-strand	161	1	15
β-strand	165-167	3	14
α-helix	168-170	3
β-strand	171-172	2	14
β-strand	178-187	10	14
α-helix	190-193	4
β-strand	196-202	7	15
α-helix	203-205	3
β-strand	207-213	7	15

Chain D: 8 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	4-7	4	16
β-strand	10-13	4	17
β-strand	19-25	7	16
β-strand	33-37	5	17
β-strand	44-48	5	17
β-strand	52-53	2	17
α-helix	54	1
β-strand	61-66	6	16
β-strand	69-74	6	16
α-helix	79-81	3
β-strand	84-88	5	17
β-strand	95	1	17
β-strand	99-103	5	17
β-strand	108	1	18
α-helix	109-110	2
β-strand	111-115	5	19
α-helix	116-118	3
α-helix	119-124	6
β-strand	126-136	11	19
β-strand	137	1	18
β-strand	141-147	7	20
β-strand	150-151	2	20
β-strand	156-160	5	19
α-helix	161-164	4
β-strand	170-179	10	19
α-helix	180-184	5
β-strand	188-195	8	20
α-helix	201	1
β-strand	202-207	6	20

Chain H: 7 helices, 24 β-strands

Element	Residues	Length	Sheet
β-strand	2-4	3	21
β-strand	8-10	3	22
β-strand	16-22	7	21
β-strand	32-37	6	23
β-strand	43-50	8	23
β-strand	55-58	4	23
α-helix	60-62	3
β-strand	66-71	6	21
β-strand	76-81	6	21
α-helix	86-88	3
β-strand	91-97	7	23
β-strand	102-105	4	23
β-strand	109-110	2	23
β-strand	111-113	3	22
β-strand	119	1	24
α-helix	120-121	2
β-strand	122-126	5	25
β-strand	133-134	2	25
β-strand	137-147	11	25
β-strand	148	1	24
β-strand	153-156	4	26
α-helix	157-159	3
β-strand	161	1	26
β-strand	165-167	3	25
α-helix	168-170	3
β-strand	171-172	2	25
β-strand	178-187	10	25
α-helix	189-191	3
β-strand	197-202	6	26
α-helix	203-205	3
β-strand	207-212	6	26

Chain I: 3 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	2	1	32
α-helix	6-9	4
β-strand	13-16	4	33
β-strand	20-21	2	34
β-strand	25-27	3	35
α-helix	36-37	2
β-strand	43-45	3	35
β-strand	46-47	2	36
β-strand	54-55	2	36
β-strand	103-104	2	34
α-helix	106-109	4
β-strand	119-120	2	35
β-strand	122	1	32
β-strand	126-131	6	33
β-strand	144-146	3	33
β-strand	148-150	3	37
β-strand	153-155	3	37

Chain J: 2 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	2	1	38
α-helix	6-8	3
β-strand	14-16	3	39
β-strand	20-21	2	40
β-strand	25-27	3	41
β-strand	43-45	3	41
β-strand	46-48	3	42
β-strand	53-55	3	42
β-strand	104-105	2	40
α-helix	108-110	3
β-strand	119-120	2	41
β-strand	122	1	38
β-strand	126-130	5	39
β-strand	144-146	3	39
β-strand	148	1	43
β-strand	155	1	43

Chain K: 2 helices, 15 β-strands

Element	Residues	Length	Sheet
β-strand	2	1	44
α-helix	6-8	3
β-strand	14-16	3	45
β-strand	19-21	3	46
β-strand	25-27	3	47
β-strand	43-45	3	47
β-strand	46-47	2	48
β-strand	54-55	2	48
β-strand	103-105	3	46
α-helix	106-109	4
β-strand	119-120	2	47
β-strand	122	1	44
β-strand	126	1	49
β-strand	128-130	3	45
β-strand	146	1	49
β-strand	148-150	3	50
β-strand	153-155	3	50

1 more chain groups are not listed. Open the entry in the viewer and use the sequence panel to see them.

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Heavy chain of Fab fragment of Basiliximab	A, C, H	protein	215	Mus musculus, Homo sapiens
Light chain of Fab fragment of Basiliximab	B, D, L	protein	210	Mus musculus, Homo sapiens	P01834 (AlphaFold model)
Interleukin-2 receptor alpha chain	I, J, K	protein	223	Homo sapiens	P01589 (AlphaFold model)

Sequence of entity 1 (A, C, H), FASTA

>3IU3_1 Heavy chain of Fab fragment of Basiliximab (chains A, C, H)
QLQQSGTVLARPGASVKMSCKASGYSFTRYWMHWIKQRPGQGLEWIGAIYPGNSDTSYNQ
KFEGKAKLTAVTSASTAYMELSSLTHEDSAVYYCSRDYGYYFDFWGQGTTLTVSSASTKG
PSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSL
SSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEP

Sequence of entity 2 (B, D, L), FASTA

>3IU3_2 Light chain of Fab fragment of Basiliximab (chains B, D, L)
QIVSTQSPAIMSASPGEKVTMTCSASSSRSYMQWYQQKPGTSPKRWIYDTSKLASGVPAR
FSGSGSGTSYSLTISSMEAEDAATYYCHQRSSYTFGGGTKLEIKRTVAAPSVFIFPPSDE
QLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSK
ADYEKHKVYACEVTHQGLSSPVTKSFNRGE

Sequence of entity 3 (I, J, K), FASTA

>3IU3_3 Interleukin-2 receptor alpha chain (chains I, J, K)
ELCDDDPPEIPHATFKAMAYKEGTMLNCECKRGFRRIKSGSLYMLCTGNSSHSSWDNQCQ
CTSSATRNTTKQVTPQPEEQKERKTTEMQSPMQPVDQASLPGHCREPPPWENEATERIYH
FVVGQMVYYQCVQGYRALHRGPAESVCKMTHGKTRWTQPQLICTGEMETSQFPGEEKPQA
SPEGRPESETSCLVTTTDFQIQTEMAATMETSIFTTEHHHHHH

Primary citation

Structural basis for the blockage of IL-2 signaling by therapeutic antibody basiliximab. Du, J., Yang, H., Zhang, D. et al. J Immunol (2010) 184:1361-1368. DOI 10.4049/jimmunol.0903178 · PubMed

Other PDB entries of the same protein (UniProt P01834 (AlphaFold model), which also has an AlphaFold model), best resolution first:

5EWI 1.6 Å, Crystal Structure of the Human Fab VRC38.01, an HIV-1 V1V2-Directed Neutralizing…
1NGZ 1.6 Å, Chimeric Germline Fab 7g12-apo
6N35 1.75 Å, Anti-HIV-1 Fab 2G12 + Man1-2 re-refinement
4XMP 1.78 Å, Crystal structure of broadly and potently neutralizing antibody VRC08 in complex with…
1N0X 1.8 Å, Crystal Structure of a Broadly Neutralizing Anti-HIV-1 Antibody in Complex with a…
3VH8 1.8 Å, KIR3DL1 in complex with HLA-B*5701
3X12 1.8 Å, Crystal structure of HLA-B*57:01.I80N
6B9Z 1.82 Å, Trastuzumab Fab v3
2VXQ 1.9 Å, Crystal structure of the major grass pollen allergen Phl p 2 in complex with its…
3D85 1.9 Å, Crystal structure of IL-23 in complex with neutralizing FAB
6BAH 1.9 Å, Trastuzumab Fab v3 with 5-diphenyl meditope variant
6DCV 1.9 Å, Crystal structure of human anti-tau antibody CBTAU-27.1

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