28QM: MBP

MBP bound to distal DARPin (AHIR dodecamer scaffold system). Determined by electron microscopy at 3.4 Å resolution. Released 25 Feb 2026.

Method: Electron microscopy
Resolution: 3.4 Å
Organisms: Homo sapiens, synthetic construct
Chains: 2
Atoms: 4,034
Mol. weight: 57.9 kDa
Ligands: EOH
Released: 25 Feb 2026

Explore 28QM in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

28QM contains 31 α-helices and 27 β-strands across 2 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: 20 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	8-11	4	1
α-helix	18-31	14
β-strand	36-39	4	1
α-helix	44-52	9
β-strand	60-64	5	1
α-helix	65-73	9
β-strand	77	1	2
α-helix	84-87	4
β-strand	90	1	3
α-helix	92-95	4
β-strand	99-100	2	4
β-strand	103-104	2	4
β-strand	106-112	7	1
β-strand	115-119	5	5
β-strand	129	1	6
α-helix	132-141	10
β-strand	146	1	7
α-helix	155-164	10
β-strand	168	1	8
β-strand	171	1	9
β-strand	178	1	9
β-strand	183	1	8
α-helix	187-201	15
α-helix	211-219	9
β-strand	223	1	7
β-strand	225-228	4	5
α-helix	230-232	3
α-helix	233-239	7
β-strand	243-246	4	5
α-helix	247-249	3
β-strand	250	1	6
β-strand	251	1	10
β-strand	254	1	10
β-strand	259-260	2	11
β-strand	261-267	7	1
β-strand	268	1	2
α-helix	274-279	6
α-helix	280-285	6
α-helix	288-297	10
β-strand	302-303	2	1
β-strand	305	1	3
α-helix	306-312	7
α-helix	316-327	12
β-strand	329-330	2	11
α-helix	331-332	2
α-helix	337-353	17
α-helix	358-369	12

Chain B: 11 helices, 0 β-strands

Element	Residues	Length
α-helix	14-24	11
α-helix	27-33	7
α-helix	50-57	8
α-helix	60-68	9
α-helix	83-90	8
α-helix	93-101	9
α-helix	116-123	8
α-helix	126-134	9
α-helix	149-155	7
α-helix	159-164	6
α-helix	165-169	5

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Maltose-binding periplasmic protein,PigG	A	protein	373	Homo sapiens	A0ACD6BAW2
DARPin	B	protein	159	synthetic construct

Sequence of entity 1 (A), FASTA

>28QM_1 Maltose-binding periplasmic protein,PigG (chains A)
KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEHPDKLEEKFPQVAATGDGPDII
FWAHDRFGGYAQSGLLAEITPAAAFQDKLYPFTWDAVRYNGKLIAYPIAVEALSLIYNKD
LLPNPPKTWEEIPALDKELKAKGKSALMFNLQEPYFTWPLIAADGGYAFKYENGKYDIKD
VGVDNAGAKAGLTFLVDLIKNKHMNADTDYSIAEAAFNKGETAMTINGPWAWSNIDTSAV
NYGVTVLPTFKGQPSKPFVGVLSAGINAASPNKELAKEFLENYLLTDEGLEAVNKDKPLG
AVALKSYEEELAKDPRIAATMENAQKGEIMPNIPQMSAFWYAVRTAVINAASGRQTVDAA
LAAAQTNGSHHAH

Sequence of entity 2 (B), FASTA

>28QM_2 DARPin (chains B)
DLGRKLLEAARAGQDDEVRILMANGADVNAADNTGTTPLHLAAYSGHLEIVEVLLKHGAD
VDASDVFGYTPLHLAAYWGHLEIVEVLLKNGADVNAMDSDGMTPLHLAAKWGYLEIVEVL
LKHGADVNAQDKFGKTPKDLARDNGNQWIYELLEAAGRA

Ligands and cofactors

ID	Name	Formula	Copies
EOH	Ethanol	C2 H6 O	1

Primary citation

An engineered symmetrical scaffold system enables high resolution imaging of small cargo proteins by cryo-electron microscopy. Ferreira, D.S.M., Noble, M., Rowland, R.J. et al. To be published.

Other PDB entries of the same protein (UniProt A0ACD6BAW2), best resolution first:

7KD5 1.55 Å, Structure of the C-terminal domain of the Menangle virus phosphoprotein (residues 329…
6ZIS 1.73 Å, Crystal structure of a CGRP receptor ectodomain heterodimer with bound high affinity…
8ZLW 2.2 Å, Crystal Structure of RDGC IQ motif/dCaM Complex
5GXT 2.25 Å, Crystal structure of PigG
8R3E 2.91 Å, Huntingtin, 1-17, MBP-N
8R2O 3.23 Å, Huntingtin-Q17, 1-66, N-MBP fusion

Browse structure collections

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