Crystal structure of the Helicobacter pylori enoyl-acyl carrier protein reductase in complex with hydroxydiphenyl ether compounds, triclosan and diclosan

2007 ◽  
Vol 69 (3) ◽  
pp. 691-694 ◽  
Author(s):  
Hyung Ho Lee ◽  
Jinho Moon ◽  
Se Won Suh
Keyword(s):  
Crystal Structure ◽  
Helicobacter Pylori ◽  
Acyl Carrier Protein ◽  
Carrier Protein

scholarly journals The 1.3-Angstrom-Resolution Crystal Structure of β-Ketoacyl-Acyl Carrier Protein Synthase II from Streptococcus pneumoniae

2003 ◽  
Vol 185 (14) ◽  
pp. 4136-4143 ◽  
Author(s):  
Allen C. Price ◽  
Charles O. Rock ◽  
Stephen W. White
Keyword(s):  
Crystal Structure ◽  
Streptococcus Pneumoniae ◽  
Active Site ◽  
Acyl Carrier Protein ◽  
Substrate Binding ◽  
Acid Synthesis ◽  
Imidazole Ring ◽  
Antibacterial Drug ◽  
Carrier Protein ◽  
Essential Components

ABSTRACT The β-ketoacyl-acyl carrier protein synthases are members of the thiolase superfamily and are key regulators of bacterial fatty acid synthesis. As essential components of the bacterial lipid metabolic pathway, they are an attractive target for antibacterial drug discovery. We have determined the 1.3 Å resolution crystal structure of the β-ketoacyl-acyl carrier protein synthase II (FabF) from the pathogenic organism Streptococcus pneumoniae. The protein adopts a duplicated βαβαβαββ fold, which is characteristic of the thiolase superfamily. The two-fold pseudosymmetry is broken by the presence of distinct insertions in the two halves of the protein. These insertions have evolved to bind the specific substrates of this particular member of the thiolase superfamily. Docking of the pantetheine moiety of the substrate identifies the loop regions involved in substrate binding and indicates roles for specific, conserved residues in the substrate binding tunnel. The active site triad of this superfamily is present in spFabF as His 303, His 337, and Cys 164. Near the active site is an ion pair, Glu 346 and Lys 332, that is conserved in the condensing enzymes but is unusual in our structure in being stabilized by an Mg2+ ion which interacts with Glu 346. The active site histidines interact asymmetrically with Lys 332, whose positive charge is closer to His 303, and we propose a specific role for the lysine in polarizing the imidazole ring of this histidine. This asymmetry suggests that the two histidines have unequal roles in catalysis and provides new insights into the catalytic mechanisms of these enzymes.

A covalent adduct of MbtN, an acyl-ACP dehydrogenase fromMycobacterium tuberculosis, reveals an unusual acyl-binding pocket

2015 ◽  
Vol 71 (4) ◽  
pp. 862-872 ◽  
Author(s):  
Ai-Fen Chai ◽  
Esther M. M. Bulloch ◽  
Genevieve L. Evans ◽  
J. Shaun Lott ◽  
Edward N. Baker ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Acyl Carrier Protein ◽  
Acyl Chain ◽  
Binding Pocket ◽  
Carrier Protein ◽  
Strongly Correlated ◽  
Steady State Kinetics ◽  
Expected Length ◽  
Acyl Chains

Mycobacterium tuberculosis(Mtb) is the causative agent of tuberculosis. Access to iron in host macrophages depends on iron-chelating siderophores called mycobactins and is strongly correlated withMtbvirulence. Here, the crystal structure of anMtbenzyme involved in mycobactin biosynthesis, MbtN, in complex with its FAD cofactor is presented at 2.30 Å resolution. The polypeptide fold of MbtN conforms to that of the acyl-CoA dehydrogenase (ACAD) family, consistent with its predicted role of introducing a double bond into the acyl chain of mycobactin. Structural comparisons and the presence of an acyl carrier protein, MbtL, in the same gene locus suggest that MbtN acts on an acyl-(acyl carrier protein) rather than an acyl-CoA. A notable feature of the crystal structure is the tubular density projecting from N(5) of FAD. This was interpreted as a covalently bound polyethylene glycol (PEG) fragment and resides in a hydrophobic pocket where the substrate acyl group is likely to bind. The pocket could accommodate an acyl chain of 14–21 C atoms, consistent with the expected length of the mycobactin acyl chain. Supporting this, steady-state kinetics show that MbtN has ACAD activity, preferring acyl chains of at least 16 C atoms. The acyl-binding pocket adopts a different orientation (relative to the FAD) to other structurally characterized ACADs. This difference may be correlated with the apparent ability of MbtN to catalyse the formation of an unusualcisdouble bond in the mycobactin acyl chain.

scholarly journals X-Ray Crystal Structure of Mycobacterium tuberculosis β-Ketoacyl Acyl Carrier Protein Synthase II (mtKasB)

2007 ◽  
Vol 366 (2) ◽  
pp. 469-480 ◽  
Author(s):  
Sudharsan Sridharan ◽  
Lei Wang ◽  
Alistair K. Brown ◽  
Lynn G. Dover ◽  
Laurent Kremer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mycobacterium Tuberculosis ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
X Ray

scholarly journals The X-ray crystal structure of β-ketoacyl [acyl carrier protein] synthase I

FEBS Letters ◽  
1999 ◽  
Vol 460 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Johan Gotthardt Olsen ◽  
Anders Kadziola ◽  
Penny von Wettstein-Knowles ◽  
Mads Siggaard-Andersen ◽  
Ylva Lindquist ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
X Ray

scholarly journals The genome of a Bacteroidetes inhabitant of the human gut encodes a structurally distinct enoyl-acyl carrier protein reductase (FabI)

2020 ◽  
Vol 295 (22) ◽  
pp. 7635-7652
Author(s):  
Christopher D. Radka ◽  
Matthew W. Frank ◽  
Jiangwei Yao ◽  
Jayaraman Seetharaman ◽  
Darcie J. Miller ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Conformational Change ◽  
Conformational Changes ◽  
Active Site ◽  
Acyl Carrier Protein ◽  
Acid Synthesis ◽  
Binding Pocket ◽  
Structural Features ◽  
Antibacterial Drug ◽  
Carrier Protein

Enoyl-acyl carrier protein reductase (FabI) catalyzes a rate-controlling step in bacterial fatty-acid synthesis and is a target for antibacterial drug development. A phylogenetic analysis shows that FabIs fall into four divergent clades. Members of clades 1–3 have been structurally and biochemically characterized, but the fourth clade, found in members of phylum Bacteroidetes, is uncharacterized. Here, we identified the unique structure and conformational changes that distinguish clade 4 FabIs. Alistipes finegoldii is a prototypical Bacteroidetes inhabitant of the gut microbiome. We found that A. finegoldii FabI (AfFabI) displays cooperative kinetics and uses NADH as a cofactor, and its crystal structure at 1.72 Å resolution showed that it adopts a Rossmann fold as do other characterized FabIs. It also disclosed a carboxyl-terminal extension that forms a helix–helix interaction that links the protomers as a unique feature of AfFabI. An AfFabI·NADH crystal structure at 1.86 Å resolution revealed that this feature undergoes a large conformational change to participate in covering the NADH-binding pocket and establishing the water channels that connect the active site to the central water well. Progressive deletion of these interactions led to catalytically compromised proteins that fail to bind NADH. This unique conformational change imparted a distinct shape to the AfFabI active site that renders it refractory to a FabI drug that targets clade 1 and 3 pathogens. We conclude that the clade 4 FabI, found in the Bacteroidetes inhabitants of the gut, have several structural features and conformational transitions that distinguish them from other bacterial FabIs.

scholarly journals Kinetic, inhibition and structural studies on 3-oxoacyl-ACP reductase from Plasmodium falciparum, a key enzyme in fatty acid biosynthesis

2005 ◽  
Vol 393 (2) ◽  
pp. 447-457 ◽  
Author(s):  
Sasala R. Wickramasinghe ◽  
Kirstine A. Inglis ◽  
Jonathan E. Urch ◽  
Sylke Müller ◽  
Daan M. F. van Aalten ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Plasmodium Falciparum ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Competitive Inhibition ◽  
Acyl Carrier Protein ◽  
Antimalarial Activity ◽  
Kinetic Properties ◽  
Carrier Protein ◽  
Acid Biosynthesis

Type II fatty acid biosynthesis represents an attractive target for the discovery of new antimalarial drugs. Previous studies have identified malarial ENR (enoyl acyl-carrier-protein reductase, or FabI) as the target for the antiseptic triclosan. In the present paper, we report the biochemical properties and 1.5 Å (1 Å=0.1 nm) crystal structure of OAR (3-oxoacyl acyl-carrier-protein reductase, or FabG), the second reductive step in fatty acid biosynthesis and its inhibition by hexachlorophene. Under optimal conditions of pH and ionic strength, Plasmodium falciparum OAR displays kinetic properties similar to those of OAR from bacteria or plants. Activity with NADH is <3% of that with NADPH. Fluorescence enhancement studies indicate that NADPH can bind to the free enzyme, consistent with kinetic and product inhibition studies suggesting a steady-state ordered mechanism. The crystal structure reveals a tetramer with a sulphate ion bound in the cofactor-binding site such that the side chains of the catalytic triad of serine, tyrosine and lysine are aligned in an active conformation, as previously observed in the Escherichia coli OAR–NADP+ complex. A cluster of positively charged residues is positioned at the entrance to the active site, consistent with the proposed recognition site for the physiological substrate (3-oxoacyl-acyl-carrier protein) in E. coli OAR. The antibacterial and anthelminthic agent hexachlorophene is a potent inhibitor of OAR (IC50 2.05 μM) displaying non-linear competitive inhibition with respect to NADPH. Hexachlorophene (EC50 6.2 μM) and analogues such as bithionol also have antimalarial activity in vitro, suggesting they might be useful leads for further development.

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