27QZ: SR Ca2+-ATPase in E2(TG) with bound B1HQ

Crystal structure of SR Ca2+-ATPase in E2(TG) with bound B1HQ. Determined by X-ray diffraction at 2.1 Å resolution. Released 15 Jul 2026.

Method: X-ray diffraction
Resolution: 2.1 Å
Organism: Oryctolagus cuniculus
Chains: 1
Atoms: 8,234
Mol. weight: 116.95 kDa
Ligands: TG1, PCW, EYK
Released: 15 Jul 2026

Explore 27QZ in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

27QZ contains 62 α-helices and 35 β-strands across 1 chain. 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: 62 helices, 35 β-strands

Element	Residues	Length	Sheet
α-helix	4-6	3
α-helix	9-16	8
β-strand	24	1	1
α-helix	26-36	11
α-helix	41-45	5
α-helix	49-55	7
α-helix	60-75	16
α-helix	84-86	3
α-helix	89-111	23
α-helix	115-119	5
α-helix	120-122	3
β-strand	126-130	5	2
β-strand	131	1	1
β-strand	138-141	4	2
α-helix	142-144	3
β-strand	150-154	5	2
α-helix	157	1
β-strand	158	1	3
α-helix	159	1
β-strand	162-168	7	2
β-strand	174-176	3	3
α-helix	178-181	4
β-strand	187-188	2	3
α-helix	201-203	3
β-strand	207-208	2	2
β-strand	213-216	4	3
β-strand	218-225	8	2
α-helix	227-229	3
α-helix	231-240	10
α-helix	245-247	3
α-helix	248-274	27
α-helix	276-280	5
α-helix	288-306	19
α-helix	311-328	18
β-strand	331-333	3	4
α-helix	338-343	6
β-strand	347-351	5	4
β-strand	357	1	5
β-strand	362-373	12	6
β-strand	376-384	9	6
β-strand	395-397	3	6
β-strand	400-401	2	6
α-helix	404-406	3
α-helix	408-419	12
β-strand	424-428	5	7
β-strand	433-437	5	7
α-helix	440-452	13
α-helix	464-468	5
α-helix	470-478	9
β-strand	479-488	10	6
β-strand	493-500	8	6
β-strand	511-516	6	6
α-helix	518-523	6
β-strand	525-530	6	6
β-strand	533-536	4	6
α-helix	539-554	16
α-helix	559	1
β-strand	560-567	8	6
α-helix	570-572	3
α-helix	573-575	3
α-helix	581-583	3
α-helix	584-587	4
β-strand	591-600	10	6
α-helix	602	1
β-strand	603	1	5
α-helix	604	1
α-helix	607-616	10
β-strand	620-625	6	4
α-helix	629-639	11
β-strand	652-654	3	4
α-helix	655-659	5
α-helix	663-672	10
β-strand	675-677	3	4
α-helix	683-692	10
β-strand	698-702	5	4
α-helix	704-713	10
β-strand	716-720	5	4
α-helix	725-730	6
β-strand	733-735	3	4
α-helix	740-781	42
α-helix	783-785	3
α-helix	789-794	6
α-helix	795-799	5
α-helix	801-807	7
α-helix	810-813	4
α-helix	816-818	3
α-helix	820-823	4
α-helix	831-858	28
α-helix	867-870	4
α-helix	873-875	3
α-helix	888-892	5
α-helix	894-913	20
α-helix	927-929	3
α-helix	931-949	19
α-helix	953-957	5
α-helix	964-974	11
α-helix	976-991	16

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Sarcoplasmic/endoplasmic reticulum calcium ATPase 1	A	protein	1002	Oryctolagus cuniculus	P04191 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>27QZ_1 Sarcoplasmic/endoplasmic reticulum calcium ATPase 1 (chains A)
XMEAAHSKSTEECLAYFGVSETTGLTPDQVKRHLEKYGHNELPAEEGKSLWELVIEQFED
LLVRILLLAACISFVLAWFEEGEETITAFVEPFVILLILIANAIVGVWQERNAENAIEAL
KEYEPEMGKVYRADRKSVQRIKARDIVPGDIVEVAVGDKVPADIRILSIKSTTLRVDQSI
LTGESVSVIKHTEPVPDPRAVNQDKKNMLFSGTNIAAGKALGIVATTGVSTEIGKIRDQM
AATEQDKTPLQQKLDEFGEQLSKVISLICVAVWLINIGHFNDPVHGGSWIRGAIYYFKIA
VALAVAAIPEGLPAVITTCLALGTRRMAKKNAIVRSLPSVETLGCTSVICSDKTGTLTTN
QMSVCKMFIIDKVDGDFCSLNEFSITGSTYAPEGEVLKNDKPIRSGQFDGLVELATICAL
CNDSSLDFNETKGVYEKVGEATETALTTLVEKMNVFNTEVRNLSKVERANACNSVIRQLM
KKEFTLEFSRDRKSMSVYCSPAKSSRAAVGNKMFVKGAPEGVIDRCNYVRVGTTRVPMTG
PVKEKILSVIKEWGTGRDTLRCLALATRDTPPKREEMVLDDSSRFMEYETDLTFVGVVGM
LDPPRKEVMGSIQLCRDAGIRVIMITGDNKGTAIAICRRIGIFGENEEVADRAYTGREFD
DLPLAEQREACRRACCFARVEPSHKSKIVEYLQSYDEITAMTGDGVNDAPALKKAEIGIA
MGSGTAVAKTASEMVLADDNFSTIVAAVEEGRAIYNNMKQFIRYLISSNVGEVVCIFLTA
ALGLPEALIPVQLLWVNLVTDGLPATALGFNPPDLDIMDRPPRSPKEPLISGWLFFRYMA
IGGYVGAATVGAAAWWFMYAEDGPGVTYHQLTHFMQCTEDHPHFEGLDCEIFEAPEPMTM
ALSVLVTIEMCNALNSLSENQSLMRMPPWVNIWLLGSICLSMSLHFLILYVDPLPMIFKL
KALDLTQWLMVLKISLPVIGLDEILKFIARNYLEDPEDERRK

Ligands and cofactors

ID	Name	Formula	Copies
TG1	Octanoic acid [3S-[3ALPHA, 3ABETA, 4ALPHA, 6BETA, 6ABETA, 7BETA, 8ALPHA(Z),…	C34 H50 O12	1
PCW	1,2-dioleoyl-sn-glycero-3-phosphocholine	C44 H85 N O8 P	7
EYK	2-tert-butylbenzene-1,4-diol	C10 H14 O2	1

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

Primary citation

Structural Basis of SERCA Inhibition by Derivatives of di-tert-butylhydroquinone Revealed by X-ray Crystallography. Kanai, R., Hirata, A., Toyoshima, C. et al. J Membr Biol (2026) 259. DOI 10.1007/s00232-026-00388-1 · PubMed

Other PDB entries of the same protein (UniProt P04191 (AlphaFold model), which also has an AlphaFold model), best resolution first:

27RD 2.0 Å, Crystal structure of SR Ca2+-ATPase in E2(TG) with bound IPP
27RC 2.1 Å, Crystal structure of SR Ca2+-ATPase in E2(TG) with bound BMP
27QY 2.12 Å, Crystal structure of SR Ca2+-ATPase in E2(TG) with bound AHQ
3AR4 2.15 Å, Calcium pump crystal structure with bound ATP and TG in the absence of Ca2+
3AR7 2.15 Å, Calcium pump crystal structure with bound TNP-ATP and TG in the absence of Ca2+
27RE 2.2 Å, Crystal structure of SR Ca2+-ATPase in E2(TG) with bound MPQ
27RF 2.2 Å, Crystal structure of SR Ca2+-ATPase in E2(TG) with bound PHQ
3AR5 2.2 Å, Calcium pump crystal structure with bound TNP-AMP and TG
3AR6 2.2 Å, Calcium pump crystal structure with bound TNP-ADP and TG in the absence of calcium
3N5K 2.2 Å, Structure Of The (Sr)Ca2+-ATPase E2-AlF4- Form
1WPG 2.3 Å, Crystal structure of the SR CA2+-ATPase with MGF4
3AR3 2.3 Å, Calcium pump crystal structure with bound ADP and TG

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