7SQI
Crosslinked Crystal Structure of Type II Fatty Acid Synthase Ketosynthase, FabB, and C14-crypto Acyl Carrier Protein, AcpP
Summary for 7SQI
| Entry DOI | 10.2210/pdb7sqi/pdb |
| Descriptor | Beta-ketoacyl-ACP synthase I, Acyl carrier protein, SODIUM ION, ... (5 entities in total) |
| Functional Keywords | ketosynthase, crosslink, fabb, acp, kasi, transferase |
| Biological source | Escherichia coli K-12 More |
| Total number of polymer chains | 4 |
| Total formula weight | 103587.30 |
| Authors | Chen, A.,Mindrebo, J.T.,Davis, T.D.,Noel, J.P.,Burkart, M.D. (deposition date: 2021-11-05, release date: 2022-08-03, Last modification date: 2024-11-13) |
| Primary citation | Chen, A.,Mindrebo, J.T.,Davis, T.D.,Kim, W.E.,Katsuyama, Y.,Jiang, Z.,Ohnishi, Y.,Noel, J.P.,Burkart, M.D. Mechanism-based cross-linking probes capture the Escherichia coli ketosynthase FabB in conformationally distinct catalytic states. Acta Crystallogr D Struct Biol, 78:1171-1179, 2022 Cited by PubMed Abstract: Ketosynthases (KSs) catalyse essential carbon-carbon bond-forming reactions in fatty-acid biosynthesis using a two-step, ping-pong reaction mechanism. In Escherichia coli, there are two homodimeric elongating KSs, FabB and FabF, which possess overlapping substrate selectivity. However, FabB is essential for the biosynthesis of the unsaturated fatty acids (UFAs) required for cell survival in the absence of exogenous UFAs. Additionally, FabB has reduced activity towards substrates longer than 12 C atoms, whereas FabF efficiently catalyses the elongation of saturated C14 and unsaturated C16:1 acyl-acyl carrier protein (ACP) complexes. In this study, two cross-linked crystal structures of FabB in complex with ACPs functionalized with long-chain fatty-acid cross-linking probes that approximate catalytic steps were solved. Both homodimeric structures possess asymmetric substrate-binding pockets suggestive of cooperative relationships between the two FabB monomers when engaged with C14 and C16 acyl chains. In addition, these structures capture an unusual rotamer of the active-site gating residue, Phe392, which is potentially representative of the catalytic state prior to substrate release. These structures demonstrate the utility of mechanism-based cross-linking methods to capture and elucidate conformational transitions accompanying KS-mediated catalysis at near-atomic resolution. PubMed: 36048156DOI: 10.1107/S2059798322007434 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.7 Å) |
Structure validation
Download full validation report
