9N74: 40S ribosomal protein S18-A

SSU processome maturation and disassembly, State H. Determined by electron microscopy at 2.65 Å resolution. Released 29 Oct 2025.

Method: Electron microscopy
Resolution: 2.65 Å
Organism: Saccharomyces cerevisiae S288C
Chains: 71
Atoms: 238,225
Mol. weight: 4693.69 kDa
Ligands: GTP, ADP, ZN, ATP
Released: 29 Oct 2025

Explore 9N74 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9N74 contains 1,182 α-helices and 1,075 β-strands across 68 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 L3: 4 helices, 4 β-strands

Element	Residues	Length	Sheet
β-strand	14-17	4	50
β-strand	20-23	4	50
β-strand	27	1	51
α-helix	28-32	5
α-helix	40-50	11
β-strand	57	1	51
α-helix	63-74	12
α-helix	101-119	19

Chain L4: 8 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	10	1	68
α-helix	16-18	3
β-strand	27	1	68
α-helix	31-32	2
β-strand	41-43	3	69
α-helix	44-45	2
α-helix	46-51	6
α-helix	58-66	9
β-strand	70-72	3	70
β-strand	75-76	2	70
β-strand	83-85	3	69
β-strand	89-92	4	70
β-strand	97-103	7	70
β-strand	109-113	5	70
α-helix	118-120	3
β-strand	121-125	5	71
β-strand	126-131	6	72
α-helix	133-135	3
β-strand	137-141	5	72
β-strand	146-148	3	72
β-strand	159-163	5	71
β-strand	168-173	6	71
β-strand	179-183	5	73
β-strand	192-199	8	73
β-strand	207-211	5	73
β-strand	217-221	5	73
α-helix	222-224	3
β-strand	225-230	6	73
β-strand	233-234	2	73

Chain L5: 8 helices, 7 β-strands

Element	Residues	Length	Sheet
β-strand	15-17	3	20
α-helix	31-36	6
β-strand	41-42	2	79
β-strand	46-47	2	79
β-strand	63	1	80
α-helix	83-86	4
β-strand	88	1	80
α-helix	89-97	9
α-helix	107-124	18
α-helix	129-139	11
β-strand	144-148	5	81
β-strand	157-161	5	81
α-helix	164-182	19
α-helix	190-203	14
α-helix	209-223	15

Chain L6: 9 helices, 15 β-strands

Element	Residues	Length	Sheet
β-strand	2-7	6	89
β-strand	12-16	5	89
α-helix	21-27	7
β-strand	31	1	90
β-strand	35-37	3	89
α-helix	38-41	4
α-helix	43-45	3
β-strand	49-57	9	89
α-helix	61	1
β-strand	62	1	89
β-strand	63	1	91
β-strand	72-77	6	91
β-strand	93-98	6	91
β-strand	101	1	90
β-strand	106-115	10	89
α-helix	120-121	2
β-strand	137	1	92
α-helix	138-145	8
α-helix	153-155	3
β-strand	160-164	5	93
β-strand	167-171	5	93
α-helix	173-175	3
β-strand	176	1	92
α-helix	181-215	35

Chain L7: 7 helices, 8 β-strands

Element	Residues	Length	Sheet
α-helix	4-7	4
β-strand	8	1	101
α-helix	15-30	16
α-helix	35-38	4
β-strand	43	1	101
β-strand	45-50	6	102
β-strand	56-63	8	102
α-helix	67-84	18
β-strand	88-95	8	102
α-helix	115-130	16
β-strand	135-142	8	103
β-strand	148-154	7	103
α-helix	159-162	4
α-helix	166-177	12
β-strand	182-184	3	103

Chain L8: 9 helices, 11 β-strands

Element	Residues	Length	Sheet
β-strand	4	1	107
α-helix	11-12	2
α-helix	16-20	5
α-helix	26-28	3
β-strand	29	1	107
β-strand	36-38	3	108
β-strand	42-47	6	108
β-strand	53-60	8	108
β-strand	62-67	6	109
β-strand	72-83	12	109
α-helix	89-92	4
β-strand	95-96	2	108
β-strand	101-105	5	109
α-helix	107-117	11
α-helix	147-150	4
α-helix	154-162	9
β-strand	164-169	6	109
α-helix	173-176	4
β-strand	181-183	3	109
α-helix	186-195	10

Chain L9: 14 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	3-7	5
α-helix	21-34	14
α-helix	39-61	23
α-helix	63	1
α-helix	67-82	16
α-helix	93-96	4
α-helix	101-105	5
β-strand	108	1	118
α-helix	109-115	7
α-helix	122-130	9
β-strand	134-136	3	119
β-strand	139-140	2	119
α-helix	146	1
β-strand	147	1	118
α-helix	148-149	2
α-helix	153-155	3
β-strand	156-158	3	119
α-helix	163-165	3
α-helix	171-181	11

Chain LC: 7 helices, 5 β-strands

Element	Residues	Length	Sheet
β-strand	6-13	8	121
β-strand	16-24	9	121
β-strand	29-31	3	121
β-strand	34-35	2	121
α-helix	36-38	3
α-helix	42-44	3
α-helix	45-55	11
α-helix	59-62	4
β-strand	63-70	8	121
α-helix	74-96	23
α-helix	99-112	14
α-helix	114-116	3

60 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
5'ETS rRNA	L0	RNA	700	Saccharomyces cerevisiae S288C
18S rRNA	L1	RNA	1802	Saccharomyces cerevisiae S288C
U3 snoRNA	L2	RNA	334	Saccharomyces cerevisiae S288C
40S ribosomal protein S18-A	L3	protein	146	Saccharomyces cerevisiae S288C	P0CX55 (AlphaFold model)
40S ribosomal protein S4-A	L4	protein	261	Saccharomyces cerevisiae S288C	P0CX35 (AlphaFold model)
40S ribosomal protein S5	L5	protein	225	Saccharomyces cerevisiae S288C	P26783 (AlphaFold model)
40S ribosomal protein S6-A	L6	protein	236	Saccharomyces cerevisiae S288C	P0CX37 (AlphaFold model)
40S ribosomal protein S7-A	L7	protein	190	Saccharomyces cerevisiae S288C	P26786
40S ribosomal protein S8-A	L8	protein	200	Saccharomyces cerevisiae S288C	P0CX39
40S ribosomal protein S9-A	L9	protein	197	Saccharomyces cerevisiae S288C	O13516
40S ribosomal protein S16-A	LC	protein	143	Saccharomyces cerevisiae S288C	P0CX51
40S ribosomal protein S11-A	LD	protein	156	Saccharomyces cerevisiae S288C	P0CX47

56 more molecules are not listed.

Sequence of entity 1 (L0), FASTA

>9N74_1 5'ETS rRNA (chains L0)
AUGCGAAAGCAGUUGAAGACAAGUUCGAAAAGAGUUUGGAAACGAAUUCGAGUAGGCUUG
UCGUUCGUUAUGUUUUUGUAAAUGGCCUCGUCAAACGGUGGAGAGAGUCGCUAGGUGAUC
GUCAGAUCUGCCUAGUCUCUAUACAGCGUGUUUAAUUGACAUGGGUUGAUGCGUAUUGAG
AGAUACAAUUUGGGAAGAAAUUCCCAGAGUGUGUUUCUUUUGCGUUUAACCUGAACAGUC
UCAUCGUGGGCAUCUUGCGAUUCCAUUGGUGAGCAGCGAAGGAUUUGGUGGAUUACUAGC
UAAUAGCAAUCUAUUUCAAAGAAUUCAAACUUGGGGGAAUGCCUUGUUGAAUAGCCGGUC
GCAAGACUGUGAUUCUUCAAGUGUAACCUCCUCUCAAAUCAGCGAUAUCAAACGUACCAU
UCCGUGAAACACCGGGGUAUCUGUUUGGUGGAACCUGAUUAGAGGAAACUCAAAGAGUGC
UAUGGUAUGGUGACGGAGUGCGCUGGUCAAGAGUGUAAAAGCUUUUUGAACAGAGAGCAU
UUCCGGCAGCAGAGAGACCUGAAAAAGCAAUUUUUCUGGAAUUUCAGCUGUUUCCAAACU
CAAUAAGUAUCUUCUAGCAAGAGGGAAUAGGUGGGAAAAAAAAAAAGAGAUUUCGGUUUC
UUUCUUUUUUACUGCUUGUUGCUUCUUCUUUUAAGAUAGU

Sequence of entity 2 (L1), FASTA

>9N74_2 18S rRNA (chains L1)
UAUCUGGUUGAUCCUGCCAGUAGUCAUAUGCUUGUCUCAAAGAUUAAGCCAUGCAUGUCU
AAGUAUAAGCAAUUUAUACAGUGAAACUGCGAAUGGCUCAUUAAAUCAGUUAUCGUUUAU
UUGAUAGUUCCUUUACUACAUGGUAUAACUGUGGUAAUUCUAGAGCUAAUACAUGCUUAA
AAUCUCGACCCUUUGGAAGAGAUGUAUUUAUUAGAUAAAAAAUCAAUGUCUUCGGACUCU
UUGAUGAUUCAUAAUAACUUUUCGAAUCGCAUGGCCUUGUGCUGGCGAUGGUUCAUUCAA
AUUUCUGCCCUAUCAACUUUCGAUGGUAGGAUAGUGGCCUACCAUGGUUUCAACGGGUAA
CGGGGAAUAAGGGUUCGAUUCCGGAGAGGGAGCCUGAGAAACGGCUACCACAUCCAAGGA
AGGCAGCAGGCGCGCAAAUUACCCAAUCCUAAUUCAGGGAGGUAGUGACAAUAAAUAACG
AUACAGGGCCCAUUCGGGUCUUGUAAUUGGAAUGAGUACAAUGUAAAUACCUUAACGAGG
AACAAUUGGAGGGCAAGUCUGGUGCCAGCAGCCGCGGUAAUUCCAGCUCCAAUAGCGUAU
AUUAAAGUUGUUGCAGUUAAAAAGCUCGUAGUUGAACUUUGGGCCCGGUUGGCCGGUCCG
AUUUUUUCGUGUACUGGAUUUCCAACGGGGCCUUUCCUUCUGGCUAACCUUGAGUCCUUG
UGGCUCUUGGCGAACCAGGACUUUUACUUUGAAAAAAUUAGAGUGUUCAAAGCAGGCGUA
UUGCUCGAAUAUAUUAGCAUGGAAUAAUAGAAUAGGACGUUUGGUUCUAUUUUGUUGGUU
UCUAGGACCAUCGUAAUGAUUAAUAGGGACGGUCGGGGGCAUCAGUAUUCAAUUGUCAGA
GGUGAAAUUCUUGGAUUUAUUGAAGACUAACUACUGCGAAAGCAUUUGCCAAGGACGUUU
UCAUUAAUCAAGAACGAAAGUUAGGGGAUCGAAGAUGAUCAGAUACCGUCGUAGUCUUAA
CCAUAAACUAUGCCGACUAGGGAUCGGGUGGUGUUUUUUUAAUGACCCACUCGGCACCUU
ACGAGAAAUCAAAGUCUUUGGGUUCUGGGGGGAGUAUGGUCGCAAGGCUGAAACUUAAAG
GAAUUGACGGAAGGGCACCACCAGGAGUGGAGCCUGCGGCUUAAUUUGACUCAACACGGG
GAAACUCACCAGGUCCAGACACAAUAAGGAUUGACAGAUUGAGAGCUCUUUCUUGAUUUU
GUGGGUGGUGGUGCAUGGCCGUUCUUAGUUGGUGGAGUGAUUUGUCUGCUUAAUUGCGAU
AACGAACGAGACCUUAACCUACUAAAUAGUGGUGCUAGCAUUUGCUGGUUAUCCACUUCU
UAGAGGGACUAUCGGUUUCAAGCCGAUGGAAGUUUGAGGCAAUAACAGGUCUGUGAUGCC
CUUAGACGUUCUGGGCCGCACGCGCGCUACACUGACGGAGCCAGCGAGUCUAACCUUGGC
CGAGAGGUCUUGGUAAUCUUGUGAAACUCCGUCGUGCUGGGGAUAGAGCAUUGUAAUUAU
UGCUCUUCAACGAGGAAUUCCUAGUAAGCGCAAGUCAUCAGCUUGCGUUGAUUACGUCCC
UGCCCUUUGUACACACCGCCCGUCGCUAGUACCGAUUGAAUGGCUUAGUGAGGCCUCAGG
AUCUGCUUAGAGAAGGGGGCAACUCCAUCUCAGAGCGGAGAAUUUGGACAAACUUGGUCA
UUUAGAGGAACUAAAAGUCGUAACAAGGUUUCNGUAGGUGAACCUGCGGAAGGAUCAUUA
AA

Sequence of entity 3 (L2), FASTA

>9N74_3 U3 snoRNA (chains L2)
XGUCGACGUACUUCAUAGGAUCAUUUCUAUAGGAAUCGUCACUCUUUGACUCUUCAAAAG
AGCCACUGAAUCCAACUUGGUUGAUGAGUCCCAUAACCUUUGUACCCCAGAGUGAGAAAC
CGAAAUUGAAUCUAAAUUAGCUUGGUCCGCAAUCCUUAGCGGUUCGGCCAUCUAUAAUUU
UGAAUAAAAAUUUUGCUUUGCCGUUGCAUUUGUAGUUUUUUCCUUUGGAAGUAAUUACAA
UAUUUUAUGGCGCGAUGAUCUUGACCCAUCCUAUGUACUUCUUUUUUGAAGGGAUAGGGC
UCUAUGGGUGGGUACAAAUGGCAGUCUGACAAGU

Sequence of entity 4 (L3), FASTA

>9N74_4 40S ribosomal protein S18-A (chains L3)
MSLVVQEQGSFQHILRLLNTNVDGNIKIVYALTTIKGVGRRYSNLVCKKADVDLHKRAGE
LTQEELERIVQIMQNPTHYKIPAWFLNRQNDITDGKDYHTLANNVESKLRDDLERLKKIR
AHRGIRHFWGLRVRGQHTKTTGRRRA

Sequence of entity 5 (L4), FASTA

>9N74_5 40S ribosomal protein S4-A (chains L4)
MARGPKKHLKRLAAPHHWLLDKLSGCYAPRPSAGPHKLRESLPLIVFLRNRLKYALNGRE
VKAILMQRHVKVDGKVRTDTTYPAGFMDVITLDATNENFRLVYDVKGRFAVHRITDEEAS
YKLGKVKKVQLGKKGVPYVVTHDGRTIRYPDPNIKVNDTVKIDLASGKITDFIKFDAGKL
VYVTGGRNLGRIGTIVHKERHDGGFDLVHIKDSLDNTFVTRLNNVFVIGEQGKPYISLPK
GKGIKLSIAEERDRRRAQQGL

Sequence of entity 6 (L5), FASTA

>9N74_6 40S ribosomal protein S5 (chains L5)
MSDTEAPVEVQEDFEVVEEFTPVVLATPIPEEVQQAQTEIKLFNKWSFEEVEVKDASLVD
YVQVRQPIFVAHTAGRYANKRFRKAQCPIIERLTNSLMMNGRNNGKKLKAVRIIKHTLDI
INVLTDQNPIQVVVDAITNTGPREDTTRVGGGGAARRQAVDVSPLRRVNQAIALLTIGAR
EAAFRNIKTIAETLAEELINAAKGSSTSYAIKKKDELERVAKSNR

Sequence of entity 7 (L6), FASTA

>9N74_7 40S ribosomal protein S6-A (chains L6)
MKLNISYPVNGSQKTFEIDDEHRIRVFFDKRIGQEVDGEAVGDEFKGYVFKISGGNDKQG
FPMKQGVLLPTRIKLLLTKNVSCYRPRRDGERKRKSVRGAIVGPDLAVLALVIVKKGEQE
LEGLTDTTVPKRLGPKRANNIRKFFGLSKEDDVRDFVIRREVTKGEKTYTKAPKIQRLVT
PQRLQRKRHQRALKVRNAQAQREAAAEYAQLLAKRLSERKAEKAEIRKRRASSLKA

Sequence of entity 8 (L7), FASTA

>9N74_8 40S ribosomal protein S7-A (chains L7)
MSAPQAKILSQAPTELELQVAQAFVELENSSPELKAELRPLQFKSIREIDVAGGKKALAI
FVPVPSLAGFHKVQTKLTRELEKKFQDRHVIFLAERRILPKPSRTSRQVQKRPRSRTLTA
VHDKILEDLVFPTEIVGKRVRYLVGGNKIQKVLLDSKDVQQIDYKLESFQAVYNKLTGKQ
IVFEIPSETH

Sequence of entity 9 (L8), FASTA

>9N74_9 40S ribosomal protein S8-A (chains L8)
MGISRDSRHKRSATGAKRAQFRKKRKFELGRQPANTKIGAKRIHSVRTRGGNKKYRALRI
ETGNFSWASEGISKKTRIAGVVYHPSNNELVRTNTLTKAAIVQIDATPFRQWFEAHYGQT
LGKKKNVKEEETVAKSKNAERKWAARAASAKIESSVESQFSAGRLYACISSRPGQSGRCD
GYILEGEELAFYLRRLTAKK

Sequence of entity 10 (L9), FASTA

>9N74_10 40S ribosomal protein S9-A (chains L9)
MPRAPRTYSKTYSTPKRPYESSRLDAELKLAGEFGLKNKKEIYRISFQLSKIRRAARDLL
TRDEKDPKRLFEGNALIRRLVRVGVLSEDKKKLDYVLALKVEDFLERRLQTQVYKLGLAK
SVHHARVLITQRHIAVGKQIVNIPSFMVRLDSEKHIDFAPTSPFGGARPGRVARRNAARK
AEASGEAADEADEADEE

Sequence of entity 11 (LC), FASTA

>9N74_11 40S ribosomal protein S16-A (chains LC)
MSAVPSVQTFGKKKSATAVAHVKAGKGLIKVNGSPITLVEPEILRFKVYEPLLLVGLDKF
SNIDIRVRVTGGGHVSQVYAIRQAIAKGLVAYHQKYVDEQSKNELKKAFTSYDRTLLIAD
SRRPEPKKFGGKGARSRFQKSYR

Sequence of entity 12 (LD), FASTA

>9N74_12 40S ribosomal protein S11-A (chains LD)
MSTELTVQSERAFQKQPHIFNNPKVKTSKRTKRWYKNAGLGFKTPKTAIEGSYIDKKCPF
TGLVSIRGKILTGTVVSTKMHRTIVIRRAYLHYIPKYNRYEKRHKNVPVHVSPAFRVQVG
DIVTVGQCRPISKTVRFNVVKVSAAAGKANKQFAKF

Ligands and cofactors

ID	Name	Formula	Copies
GTP	Guanosine-5'-triphosphate	C10 H16 N5 O14 P3	1
ADP	Adenosine-5'-diphosphate	C10 H15 N5 O10 P2	1
ZN	Zinc ion	Zn	3
ATP	Adenosine-5'-triphosphate	C10 H16 N5 O13 P3	1
MG	Magnesium ion	Mg	39

Primary citation

Helicase-mediated mechanism of SSU processome maturation and disassembly. Buzovetsky, O., Klinge, S. Nature (2025) 648:746-754. DOI 10.1038/s41586-025-09688-3 · PubMed

Other PDB entries of the same protein (UniProt P0CX55 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9PN5 1.75 Å, Composite map of hypomethylated 80S ribosome treated with hygromycin B
8CCS 1.97 Å, 80S S. cerevisiae ribosome with ligands in hybrid-1 pre-translocation (PRE-H1) complex
8CDR 2.04 Å, Translocation intermediate 2 (TI-2) of 80S S. cerevisiae ribosome with ligands and eEF2…
8CEH 2.05 Å, Translocation intermediate 4 (TI-4) of 80S S. cerevisiae ribosome with ligands and eEF2…
8EVT 2.2 Å, Hypopseudouridylated yeast 80S bound with Taura syndrome virus (TSV) internal ribosome…
8T2Y 2.2 Å, Hypomethylated yeast 80S bound with cycloheximide, P-site tRNA, and A-site tRNA,…
8CGN 2.28 Å, Non-rotated 80S S. cerevisiae ribosome with ligands
8ZHC 2.3 Å, pre-frameshift complex of yeast 80S ribosome with eRF1 and mRNA of WNV
8EVP 2.38 Å, Hypopseudouridylated yeast 80S bound with Taura syndrome virus (TSV) internal ribosome…
9DP7 2.38 Å, Hypopseudouridylated yeast 80S bound with Taura syndrome virus (TSV) internal ribosome…
7ZW0 2.4 Å, FAP-80S Complex - Rotated state
8BN3 2.4 Å, Yeast 80S, ES7s delta, eIF5A, Stm1 containing

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