7MCI: Nitrogenase molybdenum-iron protein alpha chain

MoFe protein from Azotobacter vinelandii with a sulfur-replenished cofactor. Determined by X-ray diffraction at 1.65 Å resolution. Released 18 May 2022.

Method: X-ray diffraction
Resolution: 1.65 Å
Organism: Azotobacter vinelandii DJ
Chains: 4
Atoms: 17,333
Mol. weight: 234.86 kDa
Ligands: CA, CLF, MO, H2S
Released: 18 May 2022

Explore 7MCI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

7MCI contains 116 α-helices and 80 β-strands across 4 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: 26 helices, 23 β-strands

Element	Residues	Length	Sheet
α-helix	6-17	12
α-helix	22-29	8
β-strand	32-34	3	1
α-helix	42-44	3
α-helix	51-53	3
β-strand	58	1	2
α-helix	63-64	2
α-helix	65-72	8
β-strand	79-83	5	3
α-helix	87-91	5
β-strand	98	1	4
β-strand	104	1	5
β-strand	108	1	5
β-strand	114-115	2	3
α-helix	120-125	6
α-helix	128-141	14
β-strand	148-152	5	3
α-helix	155-158	4
α-helix	163-174	12
β-strand	178-181	4	3
α-helix	191-205	15
β-strand	222-228	7	6
β-strand	231	1	4
α-helix	236-244	9
β-strand	248-254	7	6
α-helix	259-264	6
α-helix	265-267	3
β-strand	270-273	4	6
α-helix	276-290	15
β-strand	294-296	3	6
β-strand	300	1	7
α-helix	301-313	13
α-helix	318-346	29
β-strand	350-353	4	1
β-strand	355	1	1
α-helix	359-362	4
α-helix	364-369	6
β-strand	373-379	7	1
α-helix	384-391	8
β-strand	399-402	4	1
β-strand	405	1	2
α-helix	406-416	11
β-strand	420-423	4	1
α-helix	425-433	9
β-strand	438-440	3	1
α-helix	444-446	3
β-strand	451	1	7
α-helix	452-467	16
α-helix	470-473	4

Chain B: 31 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	4	1	8
β-strand	7	1	8
α-helix	11-14	4
α-helix	18-27	10
α-helix	28-32	5
α-helix	34-36	3
α-helix	37-47	11
α-helix	50-56	7
β-strand	63-64	2	3
α-helix	71-80	10
β-strand	82	1	9
β-strand	85-90	6	10
α-helix	93-107	15
β-strand	114-115	2	10
α-helix	122-125	4
α-helix	128-142	15
β-strand	146-151	6	10
α-helix	153-158	6
α-helix	162-171	10
β-strand	183	1	10
α-helix	193-209	17
α-helix	210-215	6
β-strand	224-227	4	11
α-helix	234-246	13
β-strand	251-253	3	11
β-strand	276	1	9
α-helix	278-283	6
α-helix	284-286	3
β-strand	289-292	4	11
α-helix	295-297	3
α-helix	299-307	9
α-helix	321-336	16
α-helix	338-341	4
α-helix	342-362	21
β-strand	366-370	5	12
α-helix	373-385	13
β-strand	389-395	7	12
α-helix	400-411	12
α-helix	414-416	3
β-strand	420-423	4	12
α-helix	427-436	10
β-strand	441-444	4	12
α-helix	448-458	11
α-helix	460-462	3
β-strand	466-468	3	12
α-helix	479-481	3
α-helix	486-508	23
α-helix	516-518	3

Chain C: 28 helices, 23 β-strands

Element	Residues	Length	Sheet
α-helix	6-17	12
α-helix	22-29	8
β-strand	32-34	3	13
α-helix	42-44	3
α-helix	51-53	3
β-strand	58	1	14
α-helix	63-64	2
α-helix	65-72	8
β-strand	79-83	5	15
α-helix	87-91	5
β-strand	98	1	16
β-strand	104	1	17
β-strand	108	1	17
β-strand	114-115	2	15
α-helix	120-125	6
α-helix	128-141	14
β-strand	148-152	5	15
α-helix	155-158	4
α-helix	163-174	12
β-strand	178-181	4	15
α-helix	191-202	12
α-helix	203-207	5
β-strand	222-228	7	18
β-strand	231	1	16
α-helix	236-244	9
β-strand	248-254	7	18
α-helix	259-264	6
α-helix	265-267	3
β-strand	270-273	4	18
α-helix	276-290	15
β-strand	294-296	3	18
β-strand	300	1	19
α-helix	301-313	13
α-helix	318-346	29
β-strand	350-353	4	13
β-strand	355	1	13
α-helix	359-362	4
α-helix	364-369	6
β-strand	373-379	7	13
α-helix	384-391	8
α-helix	395	1
β-strand	399-402	4	13
β-strand	405	1	14
α-helix	406-416	11
β-strand	420-423	4	13
α-helix	425-433	9
β-strand	438-440	3	13
α-helix	444-446	3
β-strand	451	1	19
α-helix	452-467	16
α-helix	470-473	4

Chain D: 31 helices, 17 β-strands

Element	Residues	Length	Sheet
β-strand	4	1	20
β-strand	7	1	20
α-helix	11-14	4
α-helix	18-27	10
α-helix	28-32	5
α-helix	34-36	3
α-helix	37-46	10
α-helix	50-56	7
β-strand	63-64	2	15
α-helix	71-80	10
β-strand	82	1	21
β-strand	85-90	6	22
α-helix	93-107	15
β-strand	114-115	2	22
α-helix	120-125	6
α-helix	128-142	15
β-strand	146-151	6	22
α-helix	153-157	5
α-helix	162-171	10
β-strand	183	1	22
α-helix	193-209	17
β-strand	224-227	4	23
α-helix	234-246	13
β-strand	251-253	3	23
β-strand	276	1	21
α-helix	278-283	6
α-helix	284-286	3
β-strand	289-292	4	23
α-helix	295-297	3
α-helix	299-304	6
α-helix	305-309	5
α-helix	321-336	16
α-helix	338-341	4
α-helix	342-362	21
β-strand	366-370	5	24
α-helix	373-385	13
β-strand	389-395	7	24
α-helix	400-411	12
α-helix	414-416	3
β-strand	420-423	4	24
α-helix	427-436	10
β-strand	441-444	4	24
α-helix	448-458	11
α-helix	460-462	3
β-strand	466-468	3	24
α-helix	479-481	3
α-helix	486-508	23
α-helix	516-518	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Nitrogenase molybdenum-iron protein alpha chain	A, C	protein	492	Azotobacter vinelandii DJ	P07328 (AlphaFold model)
Nitrogenase molybdenum-iron protein beta chain	B, D	protein	523	Azotobacter vinelandii DJ	P07329 (AlphaFold model)

Sequence of entity 1 (A, C), FASTA

>7MCI_1 Nitrogenase molybdenum-iron protein alpha chain (chains A, C)
MTGMSREEVESLIQEVLEVYPEKARKDRNKHLAVNDPAVTQSKKCIISNKKSQPGLMTIR
GCAYAGSKGVVWGPIKDMIHISHGPVGCGQYSRAGRRNYYIGTTGVNAFVTMNFTSDFQE
KDIVFGGDKKLAKLIDEVETLFPLNKGISVQSECPIGLIGDDIESVSKVKGAELSKTIVP
VRCEGFRGVSQSLGHHIANDAVRDWVLGKRDEDTTFASTPYDVAIIGDYNIGGDAWSSRI
LLEEMGLRCVAQWSGDGSISEIELTPKVKLNLVHCYRSMNYISRHMEEKYGIPWMEYNFF
GPTKTIESLRAIAAKFDESIQKKCEEVIAKYKPEWEAVVAKYRPRLEGKRVMLYIGGLRP
RHVIGAYEDLGMEVVGTGYEFAHNDDYDRTMKEMGDSTLLYDDVTGYEFEEFVKRIKPDL
IGSGIKEKFIFQKMGIPFREMHSWDYSGPYHGFDGFAIFARDMDMTLNNPCWKKLQAPWE
ASEGAEKVAASA

Sequence of entity 2 (B, D), FASTA

>7MCI_2 Nitrogenase molybdenum-iron protein beta chain (chains B, D)
MSQQVDKIKASYPLFLDQDYKDMLAKKRDGFEEKYPQDKIDEVFQWTTTKEYQELNFQRE
ALTVNPAKACQPLGAVLCALGFEKTMPYVHGSQGCVAYFRSYFNRHFREPVSCVSDSMTE
DAAVFGGQQNMKDGLQNCKATYKPDMIAVSTTCMAEVIGDDLNAFINNSKKEGFIPDEFP
VPFAHTPSFVGSHVTGWDNMFEGIARYFTLKSMDDKVVGSNKKINIVPGFETYLGNFRVI
KRMLSEMGVGYSLLSDPEEVLDTPADGQFRMYAGGTTQEEMKDAPNALNTVLLQPWHLEK
TKKFVEGTWKHEVPKLNIPMGLDWTDEFLMKVSEISGQPIPASLTKERGRLVDMMTDSHT
WLHGKRFALWGDPDFVMGLVKFLLELGCEPVHILCHNGNKRWKKAVDAILAASPYGKNAT
VYIGKDLWHLRSLVFTDKPDFMIGNSYGKFIQRDTLHKGKEFEVPLIRIGFPIFDRHHLH
RSTTLGYEGAMQILTTLVNSILERLDEETRGMQATDYNHDLVR

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	2
CLF	FE(8)-S(7) cluster	Fe8 S7	2
MO	Molybdenum atom	Mo	6
H2S	Hydrosulfuric acid	H2 S	2
ICS	iron-sulfur-molybdenum cluster with interstitial carbon	C Fe7 Mo S9	2
HCA	3-hydroxy-3-carboxy-adipic acid	C7 H10 O7	2

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

Primary citation

Evidence of substrate binding and product release via belt-sulfur mobilization of the nitrogenase cofactor. Lee, C.C., Kang, W., Jasniewski, A.J. et al. Nat Catal (2022) 5:443-454. DOI 10.1038/s41929-022-00782-7

Other PDB entries of the same protein (UniProt P07328 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3U7Q 1.0 Å, A. vinelandii nitrogenase MoFe protein at atomic resolution
1M1N 1.16 Å, Nitrogenase MoFe protein from Azotobacter vinelandii
7JRF 1.33 Å, Co-co-bound nitrogenase mofe-protein from a. Vinelandii
6O7M 1.4 Å, Nitrogenase MoFeP mutant F99Y from Azotobacter vinelandii in the indigo carmine oxidized…
4TKU 1.43 Å, Reactivated Nitrogenase MoFe-protein from A. vinelandii
4TKV 1.5 Å, CO-bound Nitrogenase MoFe-protein from A. vinelandii
5BVH 1.53 Å, CO-bound form of Selenium incorporated nitrogenase MoFe-protein (Av1-Se-CO) from A.…
8P8G 1.55 Å, Nitrogenase MoFe protein from A. vinelandii beta double mutant D353G/D357G
5BVG 1.6 Å, Selenium incorporated nitrogenase MoFe-protein (Av1-Se2B) from A. vinelandii
6OP3 1.6 Å, Selenium incorporated FeMo-cofactor of nitrogenase from Azotobacter vinelandii with low…
6BBL 1.68 Å, Crystal structure of the a-96Gln MoFe protein variant in the presence of the substrate…
6O7P 1.7 Å, Nitrogenase MoFeP mutant F99Y from Azotobacter vinelandii in the dithionite reduced state

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