9MZW: PP2A-B55 holoenzyme

PP2A-B55 holoenzyme. Determined by electron microscopy at 3.16 Å resolution. Released 10 Sept 2025.

Method: Electron microscopy
Resolution: 3.16 Å
Organism: Homo sapiens
Chains: 3
Atoms: 10,476
Mol. weight: 152.89 kDa
Released: 10 Sept 2025

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

Secondary structure: helices and β-sheets

9MZW contains 88 α-helices and 45 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: 64 helices, 0 β-strands

Element	Residues	Length
α-helix	11-19	9
α-helix	25-33	9
α-helix	35-42	8
α-helix	44-46	3
α-helix	47-51	5
α-helix	52-56	5
α-helix	63-74	12
α-helix	86-89	4
α-helix	90-96	7
α-helix	102-116	15
α-helix	121-123	3
α-helix	124-128	5
α-helix	129-136	8
α-helix	141-147	7
α-helix	148-150	3
α-helix	155-157	3
α-helix	160-174	15
α-helix	179-187	9
α-helix	189-194	6
α-helix	198-200	3
α-helix	201-205	5
α-helix	206-213	8
α-helix	218-221	4
α-helix	224-232	9
α-helix	240-244	5
α-helix	245-252	8
α-helix	257-265	9
α-helix	267-274	8
α-helix	276-278	3
α-helix	279-283	5
α-helix	284-291	8
α-helix	296-304	9
α-helix	306-311	6
α-helix	318-321	4
α-helix	322-326	5
α-helix	327-334	8
α-helix	339-349	11
α-helix	350-352	3
α-helix	353-356	4
α-helix	358-360	3
α-helix	361-365	5
α-helix	366-373	8
α-helix	378-394	17
α-helix	400-411	12
α-helix	417-432	16
α-helix	435-442	8
α-helix	444-450	7
α-helix	456-473	18
α-helix	475-477	3
α-helix	478-482	5
α-helix	483-488	6
α-helix	489-491	3
α-helix	495-512	18
α-helix	514-516	3
α-helix	517-521	5
α-helix	522-527	6
α-helix	528-530	3
α-helix	534-547	14
α-helix	548-550	3
α-helix	553-555	3
α-helix	556-560	5
α-helix	561-566	6
α-helix	567-569	3
α-helix	573-583	11

Chain B: 10 helices, 31 β-strands

Element	Residues	Length	Sheet
β-strand	12-18	7	1
β-strand	35-36	2	2
β-strand	42-47	6	2
β-strand	51-57	7	2
α-helix	58-59	2
α-helix	68-70	3
β-strand	71-78	8	2
β-strand	83-85	3	3
β-strand	90-92	3	3
α-helix	93	1
β-strand	98-101	4	4
α-helix	102-103	2
β-strand	109-114	6	4
β-strand	119-132	14	4
β-strand	156-172	17	4
β-strand	182-185	4	5
β-strand	191-195	5	5
β-strand	199-204	6	5
β-strand	207-216	10	5
α-helix	222-224	3
β-strand	232-234	3	6
β-strand	242-245	4	6
β-strand	251-254	4	6
β-strand	267-269	3	6
α-helix	271-273	3
α-helix	275-277	3
β-strand	290-293	4	7
β-strand	299-303	5	7
β-strand	307-312	6	7
β-strand	321-324	4	7
α-helix	327-332	6
α-helix	333-338	6
β-strand	348-350	3	8
β-strand	356-360	5	8
β-strand	365-370	6	8
β-strand	376-380	5	8
β-strand	395	1	8
α-helix	410-412	3
β-strand	421-424	4	1
β-strand	430-434	5	1
β-strand	439-444	6	1

Chain C: 14 helices, 14 β-strands

Element	Residues	Length	Sheet
α-helix	2-17	16
α-helix	25-39	15
β-strand	45-48	4	9
α-helix	49	1
β-strand	52-55	4	10
α-helix	62-72	11
β-strand	80-82	3	10
α-helix	93-106	14
β-strand	113	1	10
α-helix	121-126	6
α-helix	130-137	8
α-helix	141-149	9
α-helix	150-152	3
β-strand	156-159	4	9
β-strand	163-166	4	9
α-helix	177-182	6
α-helix	188-190	3
α-helix	194-200	7
β-strand	202-203	2	11
β-strand	210-211	2	11
β-strand	218-220	3	11
α-helix	222-232	11
β-strand	236-239	4	9
β-strand	248-251	4	9
β-strand	256-259	4	9
α-helix	265-267	3
β-strand	274-278	5	10
β-strand	285-288	4	10

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A alpha isoform	A	protein	584	Homo sapiens	P30153 (AlphaFold model)
Serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B alpha isoform	B	protein	451	Homo sapiens	P63151 (AlphaFold model)
Serine/threonine-protein phosphatase 2A catalytic subunit alpha isoform	C	protein	311	Homo sapiens	P67775 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9MZW_1 Serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A alpha isoform (chains A)
GHMSLYPIAVLIDELRNEDVQLRLNSIKKLSTIALALGVERTRSELLPFLTDTIYDEDEV
LLALAEQLGTFTTLVGGPEYVHCLLPPLESLATVEETVVRDKAVESLRAISHEHSPSDLE
AHFVPLVKRLAGGDWFTSRTSACGLFSVCYPRVSSAVKAELRQYFRNLCSDDTPMVRRAA
ASKLGEFAKVLELDNVKSEIIPMFSNLASDEQDSVRLLAVEACVNIAQLLPQEDLEALVM
PTLRQAAEDKSWRVRYMVADKFTELQKAVGPEITKTDLVPAFQNLMKDCEAEVRAAASHK
VKEFCENLSADCRENVIMSQILPCIKELVSDANQHVKSALASVIMGLSPILGKDNTIEHL
LPLFLAQLKDECPEVRLNIISNLDCVNEVIGIRQLSQSLLPAIVELAEDAKWRVRLAIIE
YMPLLAGQLGVEFFDEKLNSLCMAWLVDHVYAIREAATSNLKKLVEKFGKEWAHATIIPK
VLAMSGDPNYLHRMTTLFCINVLSEVCGQDITTKHMLPTVLRMAGDPVANVRFNVAKSLQ
KIGPILDNSTLQSEVKPILEKLTQDQDVDVKYFAQEALTVLSLA

Sequence of entity 2 (B), FASTA

>9MZW_2 Serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B alpha isoform (chains B)
GHMGSAGAGGGNDIQWCFSQVKGAVDDDVAEADIISTVEFNHSGELLATGDKGGRVVIFQ
QEQENKIQSHSRGEYNVYSTFQSHEPEFDYLKSLEIEEKINKIRWLPQKNAAQFLLSTND
KTIKLWKISERDKRPEGYNLKEEDGRYRDPTTVTTLRVPVFRPMDLMVEASPRRIFANAH
TYHINSISINSDYETYLSADDLRINLWHLEITDRSFNIVDIKPANMEELTEVITAAEFHP
NSCNTFVYSSSKGTIRLCDMRASALCDRHSKLFEEPEDPSNRSFFSEIISSISDVKFSHS
GRYMMTRDYLSVKIWDLNMENRPVETYQVHEYLRSKLCSLYENDCIFDKFECCWNGSDSV
VMTGSYNNFFRMFDRNTKRDITLEASRENNKPRTVLKPRKVCASGKRKKDEISVDSLDFN
KKILHTAWHPKENIIAVATTNNLYIFQDKVN

Sequence of entity 3 (C), FASTA

>9MZW_3 Serine/threonine-protein phosphatase 2A catalytic subunit alpha isoform (chains C)
GHMDEKVFTKELDQWIEQLNECKQLSESQVKSLCEKAKEILTKESNVQEVRCPVTVCGDV
HGQFHDLMELFRIGGKSPDTNYLFMGDYVDRGYYSVETVTLLVALKVRYRERITILRGNH
ESRQITQVYGFYDECLRKYGNANVWKYFTDLFDYLPLTALVDGQIFCLHGGLSPSIDTLD
HIRALDRLQEVPHEGPMCDLLWSDPDDRGGWGISPRGAGYTFGQDISETFNHANGLTLVS
RAHQLVMEGYNWCHDRNVVTIFSAPNYCYRCGNQAAIMELDDTLKYSFLQFDPAPRRGEP
HVTRRTPDYFL

Primary citation

Cryo-EM structures reveal the PP2A-B55 alpha and Eya3 interaction that can be disrupted by a peptide inhibitor. Shi, S., Li, X., Alderman, C. et al. J Biol Chem (2025) 301:110287-110287. DOI 10.1016/j.jbc.2025.110287 · PubMed

Other PDB entries of the same protein (UniProt P30153 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1B3U 2.3 Å, Crystal structure of constant regulatory domain of human PP2A, PR65ALPHA
4I5L 2.43 Å, Structural mechanism of trimeric PP2A holoenzyme involving PR70: insight for Cdc6…
8TWE 2.55 Å, Cryo-EM structure of the PP2A:B55-FAM122A complex, B55 body
2IE4 2.6 Å, Structure of the Protein Phosphatase 2A Core Enzyme Bound to okadaic acid
9C6B 2.6 Å, PP2A:B55-p107 substrate complex
8TWI 2.69 Å, Cryo-EM structure of the PP2A:B55-FAM122A complex, PP2Ac body
8U1X 2.7 Å, The structure of the PP2A-B56Delta holoenzyme mutant - E197K
9C7T 2.7 Å, PP2A:B55-Eya3 substrate complex
8TTB 2.77 Å, Cryo-EM structure of the PP2A:B55-ARPP19 complex
8SO0 2.8 Å, Cryo-EM structure of the PP2A:B55-FAM122A complex
2IE3 2.8 Å, Structure of the Protein Phosphatase 2A Core Enzyme Bound to Tumor-inducing Toxins
3C5W 2.8 Å, Complex between PP2A-specific methylesterase PME-1 and PP2A core enzyme

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