PDBsum entry 2eft

Transferase

PDB id: 2eft

Contents

Protein chains

317 a.a. *

Ligands

SO4 ×2

COA

MEE ×2

Waters ×267

* Residue conservation analysis

PDB id:

2eft

Name:

Transferase

Title:

Methanethiol-cys 112 inhibition complex of e. Coli ketoacyl synthase iii (fabh) and coenzyme a (high concentration (1.7mm) soak)

Structure:

3-oxoacyl-[acyl-carrier-protein] synthase 3. Chain: a, b. Synonym: 3-oxoacyl- [acyl-carrier-protein] synthase iii, beta- ketoacyl-acp synthase iii, kas iii, ecfabh. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: fabh. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.00Å R-factor: 0.199 R-free: 0.246

Authors:

M.M.Alhamadsheh,F.Musayev,A.A.Komissarov,S.Sachdeva,H.T.Wright, N.Scarsdale,G.Florova,K.A.Reynolds

Key ref:

M.M.Alhamadsheh et al. (2007). Alkyl-CoA Disulfides as Inhibitors and Mechanistic Probes for FabH Enzymes. Chem Biol, 14, 513-524. PubMed id: 17524982 DOI: 10.1016/j.chembiol.2007.03.013

Date:

24-Feb-07 Release date: 12-Jun-07

Protein chains

P0A6R0  (FABH_ECOLI) -  Beta-ketoacyl-[acyl-carrier-protein] synthase III from Escherichia coli (strain K12)

Seq: 317 a.a.

Struc: 317 a.a.

Enzyme reactions

• Enzyme class: E.C.2.3.1.180 - beta-ketoacyl-[acyl-carrier-protein] synthase Iii.
• Reaction: malonyl-[ACP] + acetyl-CoA + H⁺ = 3-oxobutanoyl-[ACP] + CO2 + CoA

malonyl-[ACP] + acetyl-CoA + H(+) = 3-oxobutanoyl-[ACP] + CO2 + CoA (Bound ligand (Het Group name = COA) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1016/j.chembiol.2007.03.013

Chem Biol 14:513-524 (2007)

PubMed id: 17524982

Alkyl-CoA Disulfides as Inhibitors and Mechanistic Probes for FabH Enzymes.

M.M.Alhamadsheh, F.Musayev, A.A.Komissarov, S.Sachdeva, H.T.Wright, N.Scarsdale, G.Florova, K.A.Reynolds.

ABSTRACT

The first step of the reaction catalyzed by the homodimeric FabH from a dissociated fatty acid synthase is acyl transfer from acyl-CoA to an active site cysteine. We report that C(1) to C(10) alkyl-CoA disulfides irreversibly inhibit Escherichia coli FabH (ecFabH) and Mycobacterium tuberculosis FabH with relative efficiencies that reflect these enzymes' differential acyl-group specificity. Crystallographic and kinetic studies with MeSSCoA show rapid inhibition of one monomer of ecFabH through formation of a methyl disulfide conjugate with this cysteine. Reaction of the second subunit with either MeSSCoA or acetyl-CoA is much slower. In the presence of malonyl-ACP, the acylation rate of the second subunit is restored to that of the native ecFabH. These observations suggest a catalytic model in which a structurally disordered apo-ecFabH dimer orders on binding either the first substrate, acetyl-CoA, or the inhibitor MeSSCoA, and is restored to a disordered state on binding of malonyl-ACP.

Selected figure(s)

Figure 1.
Figure 1. FabH Inhibition by Alkyl-CoA Disulfides
(A) Chemical structures of alkyl-CoA disulfides 1–5.
(B) Proposed mechanism of ecFabH inactivation by MeSSCoA (1). Cys112 of ecFabH forms a methyl disulfide conjugate upon incubation with MeSSCoA (1). The released CoA in the CoA binding channel may be retained or dissociated.

Figure 5.
Figure 5. Crystal Structure of the ecFabH-MeSSCoA Soaked Complex
Stereo figure showing electron density for (A) the CoA and MeS-Cys112 in the A subunit of the ecFabH-MeSSCoA (1) complex (0.16 mM) contoured at a level of 0.9σ, and (B) electron density of the corresponding site in the B subunit. Electron density of nearby groups is omitted for clarity.

The above figures are reprinted by permission from Cell Press: Chem Biol (2007, 14, 513-524) copyright 2007.

Figures were selected by an automated process.