Structure and catalytic mechanisms of leukotriene A4 hydrolase

doi:10.1016/j.prostaglandins.2007.01.006

Prostaglandins & Other Lipid Mediators

Volume 83, Issue 3, May 2007, Pages 198-202

https://doi.org/10.1016/j.prostaglandins.2007.01.006 Get rights and content

Abstract

Leukotriene A4 hydrolase catalyzes the final and committed step in the biosynthesis of leukotriene B4, a potent chemotactic agent for neutrophils, eosinophils, monocytes, and T-cells that play key roles in the innate immune response. Recent data strongly implicates leukotriene B4 in the pathogenesis of cardiovascular diseases, in particular arteriosclerosis, myocardial infarction and stroke. Here, we highlight the most salient features of leukotriene A4 hydrolase with emphasis on its biochemistry and structure biology.

Section snippets

Leukotriene A₄ hydrolase—a zinc-dependent epoxide hydrolase with aminopeptidase activity

LTA4H is a widely distributed soluble enzyme, which has been purified from several mammalian sources [11]. The cDNAs encoding the human, mouse, rat, and guinea-pig enzymes have been cloned and sequenced. Human LTA4H exists as a single copy gene with a size of >35 kbp on chromosome 12q22 [12]. The coding sequence is divided into 19 exons and the 5′ upstream region (approximately 4 kbp) contains a phorbol-ester response element (AP-2) and two xenobiotic response elements, the functional

The zinc-binding ligands and identification of catalytic amino acid residues

The three zinc-binding ligands in LTA4H correspond to His-295, His-299, and Glu-318 and point mutations of any of these residues lead to a concomitant loss of the metal and both catalytic activities [23]. The conserved residue Glu-296 in the motif HEXXH was identified as the general base of the peptidase reaction without any role in the epoxide hydrolase reaction [24], [25]. Sequence comparisons with aminopeptidase N suggested that Tyr-383 might act as a proton donor in peptide hydrolysis and

Crystal structure and proposed reaction mechanisms of LTA₄ hydrolase

The structure of LTA4H in complex with the competitive inhibitor bestatin has been determined [31]. The protein molecule is folded into three domains: N-terminal, catalytic, and C-terminal, that are packed in a flat triangular arrangement creating a deep cleft in between. The zinc site is located at the bottom of the interdomain cleft and, as predicted, the metal is bound to His-295, His-299, and Glu-318. In the vicinity of the zinc, the catalytic residues Glu-271, Glu-296 and Tyr-383 are

Acknowledgments

This work was financially supported by the Swedish Medical Research Council (O3X-10350), the European Union (LSHM-CT-2004-005033), AFA Health Foundation, and Konung Gustav V:s 80-Årsfond.

References (33)

V.R. Jala et al.
Leukotrienes and atherosclerosis: new roles for old mediators
Trends Immunol
(2004)
N. Ohishi et al.
Leukotriene A₄ hydrolase in the human lung. Inactivation of the enzyme with leukotriene A₄ isomers
J Biol Chem
(1987)
J.Z. Haeggström et al.
Leukotriene A₄ hydrolase: a zinc metalloenzyme
Biochem Biophys Res Commun
(1990)
J.Z. Haeggström et al.
Leukotriene A₄ hydrolase: an epoxide hydrolase with peptidase activity
Biochem Biophys Res Commun
(1990)
M. Minami et al.
Leukotriene A₄ hydrolase is a zinc-containing aminopeptidase
Biochem Biophys Res Commun
(1990)
A. Wetterholm et al.
Leukotriene A₄ hydrolase: an anion activated peptidase
Biochim Biophys Acta
(1992)
L. Orning et al.
The bifunctional enzyme leukotriene A₄ hydrolase is an arginine aminopeptidase of high efficiency and specificity
J Biol Chem
(1994)
M. Minami et al.
Leukotriene A₄ hydrolase, a bifunctional enzyme. Distinction of leukotriene A₄ hydrolase and aminopeptidase activities by site-directed mutagenesis at Glu-297
FEBS Lett
(1992)
P.C. Rudberg et al.
Leukotriene A₄ hydrolase/aminopeptidase: glutamate 271 is a catalytic residue with specific roles in two distinct enzyme mechanisms
J Biol Chem
(2002)
P.C. Rudberg et al.
Leukotriene A₄ hydrolase: identification of a common carboxylate recognition site for the epoxide hydrolase and aminopeptidase substrates
J Biol Chem
(2004)

A.L. Maycock et al.

Leukotriene A₄: preparation and enzymatic conversion in a cell-free system to leukotriene B₄

J Biol Chem

(1982)

B. Samuelsson

Leukotrienes: mediators of immediate hypersensitivity reactions and inflammation

Science

(1983)

C.D. Funk

Prostaglandins and leukotrienes: advances in eicosanoid biology

Science

(2001)

K. Goodarzi et al.

Leukotriene B₄ and BLT₁ control cytotoxic effector T Cell recruitment to inflamed tissues

Nat Immunol

(2003)

V.L. Ott et al.

Mast cell-dependent migration of effector Cd8+ T cells through production of leukotriene B₄

Nat Immunol

(2003)

A.M. Tager et al.

Leukotriene B₄ receptor BLT₁ mediates early effector T cell recruitment

Nat Immunol

(2003)

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We demonstrated that this degradation was critical to limit inflammation [10] and to prevent pathological epithelial remodelling [9]. LTA4H classically functions intracellularly to catalyse the generation of pro-inflammatory lipid mediator leukotriene B4 (LTB4) [11,12]. LTB4 can drive the recruitment and activation of an array of cells including neutrophils and is implicated in protection against micro-organisms but also in the pathology of multiple diseases [13].
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Moreover, LTA4 may degrade non-enzymatically to trans (tr)-LTB4 isomers, and the intermediate 5-HPETE can be reduced to 5-HETE (Haeggstrom and Funk, 2011; Radmark et al., 2015). LTA4H is a ubiquitously expressed, soluble Zn2+ metalloenzyme that harbors two distinct enzymatic activities with overlapping active sites: (1) an epoxide hydrolase activity that converts LTA4 to the pro-inflammatory chemoattractant LTB4 and (2) an aminopeptidase activity that, for instance, hydrolyses the pro-inflammatory tripeptide Pro-Gly-Pro (PGP) (Haeggstrom et al., 2007; Snelgrove et al., 2010; Stsiapanava et al., 2017). Recently, host-derived LTB4 was shown to be critical for neutrophil recruitment and resistance to pulmonary A. fumigatus challenge in mice (Caffrey-Carr et al., 2017).
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Structure and catalytic mechanisms of leukotriene A4 hydrolase

Abstract

Section snippets

Leukotriene A4 hydrolase—a zinc-dependent epoxide hydrolase with aminopeptidase activity

The zinc-binding ligands and identification of catalytic amino acid residues

Crystal structure and proposed reaction mechanisms of LTA4 hydrolase

Acknowledgments

Trends Immunol

J Biol Chem

Biochem Biophys Res Commun

Biochem Biophys Res Commun

Biochem Biophys Res Commun

Biochim Biophys Acta

J Biol Chem

FEBS Lett

J Biol Chem

J Biol Chem

J Biol Chem

Leukotrienes: mediators of immediate hypersensitivity reactions and inflammation

Science

Prostaglandins and leukotrienes: advances in eicosanoid biology

Science

Leukotriene B4 and BLT1 control cytotoxic effector T Cell recruitment to inflamed tissues

Nat Immunol

Mast cell-dependent migration of effector Cd8+ T cells through production of leukotriene B4

Nat Immunol

Leukotriene B4 receptor BLT1 mediates early effector T cell recruitment

Nat Immunol

Structure and catalytic mechanisms of leukotriene A₄ hydrolase

Leukotriene A₄ hydrolase—a zinc-dependent epoxide hydrolase with aminopeptidase activity

Crystal structure and proposed reaction mechanisms of LTA₄ hydrolase

Leukotriene B₄ and BLT₁ control cytotoxic effector T Cell recruitment to inflamed tissues

Mast cell-dependent migration of effector Cd8+ T cells through production of leukotriene B₄

Leukotriene B₄ receptor BLT₁ mediates early effector T cell recruitment