1MR1: Smad4-Ski Complex

Crystal Structure of a Smad4-Ski Complex. Determined by X-ray diffraction at 2.85 Å resolution. Released 21 Jan 2003.

Method: X-ray diffraction
Resolution: 2.85 Å
Organism: Homo sapiens
Chains: 4
Atoms: 4,684
Mol. weight: 74.45 kDa
Ligands: ZN
Released: 21 Jan 2003

Explore 1MR1 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1MR1 contains 23 α-helices and 36 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: 7 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	322-330	9	1
β-strand	333-334	2	1
α-helix	337-338	2
β-strand	339-342	4	1
β-strand	347-351	5	2
β-strand	361-363	3	2
α-helix	374-380	7
β-strand	387-392	6	2
β-strand	396-401	6	2
β-strand	407-410	4	1
α-helix	412-418	7
β-strand	426-429	4	1
α-helix	430	1
β-strand	434-438	5	2
α-helix	440-455	16
β-strand	500-504	5	1
α-helix	518-520	3
β-strand	524-529	6	1
α-helix	530-539	10

Chain B: 7 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	322-330	9	3
β-strand	333-334	2	3
β-strand	339-342	4	3
β-strand	347-351	5	4
β-strand	361-363	3	4
α-helix	364-366	3
α-helix	374-381	8
β-strand	387-392	6	4
β-strand	396-401	6	4
β-strand	407-410	4	3
α-helix	412-418	7
β-strand	426-429	4	3
β-strand	434-438	5	4
α-helix	440-448	9
α-helix	493-496	4
β-strand	500-504	5	3
α-helix	518-520	3
β-strand	524-529	6	3
α-helix	530-540	11

Chain C: 5 helices, 6 β-strands

Element	Residues	Length	Sheet
β-strand	219-222	4	5
β-strand	228-232	5	5
α-helix	234-236	3
β-strand	245-247	3	5
β-strand	253-254	2	5
α-helix	256-259	4
β-strand	271-274	4	3
α-helix	278-280	3
α-helix	281-284	4
β-strand	286-287	2	5
α-helix	296-310	15

Chain D: 4 helices, 6 β-strands

Element	Residues	Length	Sheet
β-strand	218-222	5	6
β-strand	228-232	5	6
α-helix	234-236	3
β-strand	245-247	3	6
β-strand	253-254	2	6
α-helix	256-259	4
β-strand	271-274	4	1
α-helix	278-283	6
β-strand	286-287	2	6
α-helix	297-308	12

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Mothers against decapentaplegic homolog 4	A, B	protein	235	Homo sapiens	Q13485 (AlphaFold model)
Ski oncogene	C, D	protein	99	Homo sapiens	P12755 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>1MR1_1 Mothers against decapentaplegic homolog 4 (chains A, B)
MAPEYWCSIAYFEMDVQVGETFKVPSSCPIVTVDGYVDPSGGDRFCLGQLSNVHRTEAIE
RARLHIGKGVQLECKGEGDVWVRCLSDHAVFVQSYYLDREAGRAPGDAVHKIYPSAYIKV
FDLRQCHRQMQQQAATAQAAAAAQAAAVAGNIPGPGSVGGIAPAISLSAAAGIGVDDLRR
LCILRMSFVKGWGPDYPRQSIKETPCWIEIHLHRALQLLDEVLHTMPIADPQPLD

Sequence of entity 2 (C, D), FASTA

>1MR1_2 Ski oncogene (chains C, D)
GSHMRVYHECFGKCKGLLVPELYSSPSAACIQCLDCRLMYPPHKFVVHSHKALENRTCHW
GFDSANWRAYILLSQDYTGKEEQARLGRCLDDVKEKFDY

Ligands and cofactors

ID	Name	Formula	Copies
ZN	Zinc ion	Zn	2

Primary citation

Structural Mechanism of Smad4 Recognition by the Nuclear Oncoprotein Ski: Insights on Ski-mediated Repression of TGF-beta Signaling. Wu, J.-W., Krawitz, A.R., Chai, J. et al. Cell (2002) 111:357-367. DOI 10.1016/S0092-8674(02)01006-1 · PubMed

Other PDB entries of the same protein (UniProt Q13485 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6YIC 1.6 Å, 14-3-3 sigma in complex with SMAD4 pS403 peptide
9HWE 1.7 Å, SMAD4 MH2, residues 314-552
9HZA 2.03 Å, SMAD4 MH2, residues 272-552
5MEY 2.05 Å, Crystal structure of Smad4-MH1 bound to the GGCGC site.
1YGS 2.1 Å, Crystal structure of the SMAD4 tumor suppressor C-terminal domain
9QE6 2.1 Å, SMAD4 MH2 domain (residues 314-552) bound by Nanobody A1 (NbA1)
5UWU 2.24 Å, Crystal Structure of SMAD4 NES Peptide in complex with CRM1-Ran-RanBP1
1U7F 2.6 Å, Crystal Structure of the phosphorylated Smad3/Smad4 heterotrimeric complex
5C4V 2.6 Å, Ski-like protein
1DD1 2.62 Å, Crystal structure analysis of the SMAD4 active fragment
1U7V 2.7 Å, Crystal Structure of the phosphorylated Smad2/Smad4 heterotrimeric complex
5MEZ 2.98 Å, Crystal structure of Smad4-MH1 bound to the GGCT site.

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