7PQN: Catalytic fragment of MASP-2

Catalytic fragment of MASP-2 in complex with ecotin. Determined by X-ray diffraction at 2.4 Å resolution. Released 18 May 2022.

Method: X-ray diffraction
Resolution: 2.4 Å
Organisms: Escherichia coli (strain K12), Homo sapiens
Chains: 6
Atoms: 6,887
Mol. weight: 108.25 kDa
Released: 18 May 2022

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

Secondary structure: helices and β-sheets

7PQN contains 45 α-helices and 89 β-strands across 6 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: 3 helices, 8 β-strands

Element	Residues	Length	Sheet
β-strand	365	1	10
α-helix	369-371	3
β-strand	375-379	5	11
β-strand	387	1	10
β-strand	391-396	6	11
β-strand	401-403	3	12
β-strand	409-412	4	11
β-strand	418-420	3	11
α-helix	427-428	2
β-strand	430-432	3	12
α-helix	433-434	2

Chain aa: 3 helices, 6 β-strands

Element	Residues	Length	Sheet
α-helix	369-371	3
β-strand	375-379	5	17
β-strand	391-396	6	17
β-strand	401-403	3	18
β-strand	409-412	4	17
β-strand	418-420	3	17
α-helix	427-428	2
β-strand	430-432	3	18
α-helix	433-434	2

Chain B: 11 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	446	1	13
β-strand	449-450	2	3
α-helix	451-452	2
β-strand	459-463	5	5
β-strand	467-473	7	5
β-strand	477-480	4	5
α-helix	482-485	4
α-helix	492-494	3
β-strand	496-499	4	5
β-strand	503	1	14
β-strand	510-512	3	5
β-strand	514-519	6	5
β-strand	534-538	5	5
α-helix	541-544	4
β-strand	545	1	15
β-strand	548	1	15
α-helix	550-551	2
β-strand	552	1	3
α-helix	553-554	2
α-helix	556-561	6
β-strand	567-572	6	3
β-strand	575	1	16
β-strand	581	1	16
β-strand	584	1	14
β-strand	586-592	7	3
α-helix	593-594	2
α-helix	595-599	5
β-strand	616-619	4	3
β-strand	627	1	13
β-strand	636-641	6	3
β-strand	646-657	12	3
β-strand	667-671	5	3
α-helix	672-675	4
α-helix	676-685	10

Chain bb: 11 helices, 22 β-strands

Element	Residues	Length	Sheet
β-strand	446	1	19
β-strand	449-450	2	7
α-helix	451-452	2
β-strand	459-463	5	9
β-strand	467-473	7	9
β-strand	477-480	4	9
α-helix	482-490	9
α-helix	493-495	3
β-strand	496-499	4	9
β-strand	503	1	20
β-strand	510-519	10	9
β-strand	534-538	5	9
α-helix	541-544	4
β-strand	545	1	21
β-strand	548	1	21
α-helix	550-551	2
β-strand	552	1	7
α-helix	553-554	2
α-helix	556-561	6
β-strand	567-572	6	7
β-strand	575	1	22
β-strand	581	1	22
β-strand	584	1	20
β-strand	586-593	8	7
α-helix	594	1
α-helix	595-599	5
β-strand	616-619	4	7
β-strand	627	1	19
β-strand	636-641	6	7
β-strand	646-657	12	7
β-strand	667-671	5	7
α-helix	672-675	4
α-helix	676-685	10

Chain C: 8 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	7-10	4
α-helix	13-17	5
β-strand	20-25	6	1
α-helix	26-29	4
α-helix	33-35	3
β-strand	36-48	13	2
β-strand	53-54	2	3
β-strand	55	1	4
β-strand	58-64	7	1
β-strand	69-75	7	1
α-helix	78-80	3
β-strand	81-83	3	3
α-helix	85	1
β-strand	86	1	5
α-helix	87-88	2
β-strand	93-98	6	2
β-strand	99	1	4
α-helix	102-105	4
β-strand	106-108	3	2
β-strand	115-120	6	1
β-strand	124-132	9	2
β-strand	137-138	2	2
β-strand	140-141	2	6

Chain D: 9 helices, 15 β-strands

Element	Residues	Length	Sheet
α-helix	7-9	3
α-helix	13-17	5
β-strand	20-25	6	6
α-helix	27-29	3
α-helix	33-35	3
β-strand	36-48	13	2
β-strand	53-54	2	7
β-strand	55	1	8
β-strand	58-64	7	6
β-strand	69-75	7	6
α-helix	78-80	3
β-strand	81-83	3	7
α-helix	85	1
β-strand	86	1	9
α-helix	87-88	2
α-helix	90-92	3
β-strand	93-98	6	2
β-strand	99	1	8
α-helix	102-105	4
β-strand	106-108	3	2
β-strand	115-120	6	6
β-strand	124-132	9	2
β-strand	137-138	2	2
β-strand	140-141	2	1

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Ecotin	C, D	protein	162	Escherichia coli (strain K12)	P23827 (AlphaFold model)
Mannan-binding lectin serine protease 2 A chain	A, aa	protein	86	Homo sapiens	O00187 (AlphaFold model)
Mannan-binding lectin serine protease 2 B chain	B, bb	protein	242	Homo sapiens	O00187 (AlphaFold model)

Sequence of entity 1 (C, D), FASTA

>7PQN_1 Ecotin (chains C, D)
MKTILPAVLFAAFATTSAWAAESVQPLEKIAPYPQAEKGMKRQVIQLTPQEDESTLKVEL
LIGQTLEVDCNLHRLGGKLENKTLEGWGYDYYVFDKVSSPVSTMMACPDGKKEKKFVTAY
LGDAGMLRYNSKLPIVVYTPDNVDVKYRVWKAEEKIDNAVVR

Sequence of entity 2 (A, aa), FASTA

>7PQN_2 Mannan-binding lectin serine protease 2 A chain (chains A, aa)
ASMTIVDCGPPDDLPSGRVEYITGPGVTTYKAVIQYSCEETFYTMKVNDGKYVCEADGFW
TSSKGEKSLPVCEPVCGLSARTTGGR

Sequence of entity 3 (B, bb), FASTA

>7PQN_3 Mannan-binding lectin serine protease 2 B chain (chains B, bb)
IYGGQKAKPGDFPWQVLILGGTTAAGALLYDNWVLTAAHAVYEQKHDASALDIRMGTLKR
LSPHYTQAWSEAVFIHEGYTHDAGFDNDIALIKLNNKVVINSNITPICLPRKEAESFMRT
DDIGTASGWGLTQRGFLARNLMYVDIPIVDHQKCTAAYEKPPYPRGSVTANMLCAGLESG
GKDSCRGDSGGALVFLDSETERWFVGGIVSWGSMNCGEAGQYGVYTKVINYIPWIENIIS
DF

Primary citation

Synergy of protease-binding sites within the ecotin homodimer is crucial for inhibition of MASP enzymes and for blocking lectin pathway activation. Nagy, Z.A., Heja, D., Bencze, D. et al. J Biol Chem (2022) 298:101985-101985. DOI 10.1016/j.jbc.2022.101985 · PubMed

Other PDB entries of the same protein (UniProt P23827 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1SLU 1.8 Å, Rat anionic N143H, E151H trypsin complexed to A86H ecotin
1IFG 2.0 Å, Crystal structure of a monomeric form of general protease inhibitor, ecotin in absence…
1N8O 2.0 Å, Crystal structure of a complex between bovine chymotrypsin and ecotin
1SLW 2.0 Å, Rat anionic N143H, E151H trypsin complexed to A86H ecotin; nickel-bound
1ECY 2.19 Å, Protease inhibitor ecotin
1FI8 2.2 Å, Rat granzyme B [N66Q] complexed to ecotin [81-84 iepd]
1SLX 2.2 Å, Rat anionic N143H, E151H trypsin complexed to A86H ecotin; zinc-bound
1XX9 2.2 Å, Crystal Structure of the FXIa Catalytic Domain in Complex with EcotinM84R
1AZZ 2.3 Å, Fiddler crab collagenase complexed to ecotin
1EZS 2.3 Å, Crystal structure of ecotin mutant M84R, W67A, G68A, Y69A, D70A bound to rat anionic…
1SLV 2.3 Å, Rat anionic N143H, E151H trypsin complexed to A86H ecotin; copper-bound
1EZU 2.4 Å, Ecotin Y69F, D70P bound to D102N trypsin

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