9KA2: Beta-ketoacyl-ACP synthase FabH from E. coli

Crystal structure of beta-ketoacyl-ACP synthase FabH from E. coli. Determined by X-ray diffraction at 1.5 Å resolution. Released 10 Sept 2025.

Method: X-ray diffraction
Resolution: 1.5 Å
Organism: Escherichia coli
Chains: 2
Atoms: 5,316
Mol. weight: 71.44 kDa
Released: 10 Sept 2025

Explore 9KA2 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9KA2 contains 36 α-helices and 38 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: 18 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	2-11	10	1
β-strand	15-18	4	2
α-helix	19-25	7
α-helix	30-37	8
β-strand	41-44	4	2
α-helix	51-66	16
α-helix	70-72	3
β-strand	75-79	5	1
β-strand	85-87	3	3
α-helix	90-98	9
β-strand	102	1	4
β-strand	105-109	5	1
α-helix	111-113	3
α-helix	114-127	14
β-strand	133-140	8	1
α-helix	142-145	4
α-helix	151-154	4
β-strand	157	1	5
β-strand	160-169	10	1
β-strand	174-181	8	6
α-helix	183-188	6
β-strand	189-190	2	7
β-strand	191-192	2	8
α-helix	193-194	2
β-strand	206-207	2	7
α-helix	209-230	22
α-helix	235-237	3
β-strand	240-243	4	6
α-helix	248-257	10
α-helix	262-264	3
β-strand	265	1	6
α-helix	269-272	4
β-strand	274	1	5
α-helix	276-278	3
α-helix	279-289	11
β-strand	298-305	8	6
β-strand	309-316	8	6

Chain B: 18 helices, 19 β-strands

Element	Residues	Length	Sheet
β-strand	2-11	10	1
β-strand	15-18	4	9
α-helix	19-25	7
α-helix	30-37	8
β-strand	41-44	4	9
α-helix	51-66	16
α-helix	70-72	3
β-strand	75-79	5	1
β-strand	85-87	3	8
α-helix	90-97	8
β-strand	102	1	6
β-strand	105-109	5	1
α-helix	111-113	3
α-helix	114-127	14
β-strand	133-141	9	1
α-helix	142-145	4
α-helix	151-154	4
β-strand	157	1	10
β-strand	159-169	11	1
β-strand	174-181	8	4
α-helix	183-188	6
β-strand	189-190	2	11
β-strand	191-192	2	3
α-helix	193-194	2
β-strand	206-207	2	11
α-helix	209-230	22
α-helix	235-237	3
β-strand	240-243	4	4
α-helix	248-258	11
α-helix	262-264	3
β-strand	265	1	4
α-helix	269-272	4
β-strand	274	1	10
α-helix	276-278	3
α-helix	279-289	11
β-strand	298-305	8	4
β-strand	309-316	8	4

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Beta-ketoacyl-[acyl-carrier-protein] synthase III	A, B	protein	337	Escherichia coli	P0A6R0 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>9KA2_1 Beta-ketoacyl-[acyl-carrier-protein] synthase III (chains A, B)
MGSSHHHHHHSSGLVPRGSHMYTKIIGTGSYLPEQVRTNADLEKMVDTSDEWIVTRTGIR
ERHIAAPNETVSTMGFEAATRAIEMAGIEKDQIGLIVVATTSATHAFPSAACQIQSMLGI
KGCPAFDVAAACAGFTYALSVADQYVKSGAVKYALVVGSDVLARTCDPTDRGTIIIFGDG
AGAAVLAASEEPGIISTHLHADGSYGELLTLPNADRVNPENSIHLTMAGNEVFKVAVTEL
AHIVDETLAANNLDRSQLDWLVPHQANLRIISATAKKLGMSMDNVVVTLDRHGNTSAASV
PCALDEAVRDGRIKPGQLVLLEAFGGGFTWGSALVRF

Primary citation

The Molecular Basis of the beta-Ketoacyl-ACP Synthase FabH in Catalyzing C-C Bond Formation of Acetoacetyl-ACP. Cai, C., Huang, Y., Zhang, L. et al. ACS Catal (2025) 15:5028-5038. DOI 10.1021/acscatal.5c01167

Other PDB entries of the same protein (UniProt P0A6R0 (AlphaFold model), which also has an AlphaFold model), best resolution first:

8D1U 1.3 Å, E. coli beta-ketoacyl-[acyl carrier protein] synthase III (FabH) with an acetylated…
6X7R 1.35 Å, E. coli beta-ketoacyl-[acyl carrier protein] synthase III (FabH) in complex with…
9KA5 1.42 Å, Crystal structure of beta-ketoacyl-ACP synthase FabH C112Q from E. coli
1HNJ 1.46 Å, Crystal structure of beta-ketoacyl-ACP synthase III + malonyl-CoA
9KA6 1.47 Å, Crystal structure of beta-ketoacyl-ACP synthase FabH C112Q in complex with acyl-ACP from…
1HND 1.6 Å, Crystal structure of beta-ketoacyl-ACP synthase III-CoA complex
5BNM 1.7 Å, E. coli FabH with Small Molecule Inhibitor 1
1EBL 1.8 Å, The 1.8 a crystal structure and active site architecture of beta-ketoacyl-[acyl carrier…
3IL9 1.85 Å, Structure of E. coli FabH
5BNR 1.89 Å, E. coli Fabh with small molecule inhibitor 2
1HNH 1.9 Å, Crystal structure of beta-ketoacyl-ACP synthase III + degraded form of acetyl-CoA
1HNK 1.9 Å, Crystal structure of beta-ketoacyl-ACP synthase III, apo tetragonal form

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