Peter C Rudberg

Lund University, Lund, Skåne, Sweden

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Publications (6)23.57 Total impact

  • No preview · Conference Paper · Mar 2006
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    ABSTRACT: Leukotriene (LT) A4 hydrolase is a bifunctional zinc metalloenzyme, which converts LTA4 into the neutrophil chemoattractant LTB4 and also exhibits an anion-dependent aminopeptidase activity. In the x-ray crystal structure of LTA4 hydrolase, Arg563 and Lys565 are found at the entrance of the active center. Here we report that replacement of Arg563, but not Lys565, leads to complete abrogation of the epoxide hydrolase activity. However, mutations of Arg563 do not seem to affect substrate binding strength, because values of Ki for LTA4 are almost identical for wild type and (R563K)LTA4 hydrolase. These results are supported by the 2.3-Å crystal structure of (R563A)LTA4 hydrolase, which does not reveal structural changes that can explain the complete loss of enzyme function. For the aminopeptidase reaction, mutations of Arg563 reduce the catalytic activity (Vmax = 0.3–20%), whereas mutations of Lys565 have limited effect on catalysis (Vmax = 58–108%). However, in (K565A)- and (K565M)LTA4 hydrolase, i.e. mutants lacking a positive charge, values of the Michaelis constant for alanine-p-nitroanilide increase significantly (Km = 480–640%). Together, our data indicate that Arg563 plays an unexpected, critical role in the epoxide hydrolase reaction, presumably in the positioning of the carboxylate tail to ensure perfect substrate alignment along the catalytic elements of the active site. In the aminopeptidase reaction, Arg563 and Lys565 seem to cooperate to provide sufficient binding strength and productive alignment of the substrate. In conclusion, Arg563 and Lys565 possess distinct roles as carboxylate recognition sites for two chemically different substrates, each of which is turned over in separate enzymatic reactions catalyzed by LTA4 hydrolase.
    Preview · Article · Jul 2004 · Journal of Biological Chemistry
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    ABSTRACT: The leukotrienes (LTs) are a family of lipid mediators involved in inflammation and allergy. Leukotriene B4 is a classical chemoattractant, which triggers adherence and aggregation of leukocytes to the endothelium at only nanomolar concentrations. In addition, leukotriene B4 modulates immune responses, participates in the host-defense against infections, and is a key mediator of PAF-induced lethal shock. Because of these powerful biological effects, leukotriene B4 is implicated in a variety of acute and chronic inflammatory diseases, e.g. nephritis, arthritis, dermatitis, and chronic obstructive pulmonary disease. The final step in the biosynthesis of leukotriene B4 is catalyzed by leukotriene A4 hydrolase, a unique bi-functional zinc metalloenzyme with an anion-dependent aminopeptidase activity. Here we describe the most recent developments regarding our understanding of the structure, function, and catalytic mechanisms of leukotriene A4 hydrolase.
    No preview · Article · Sep 2002 · Prostaglandins & other lipid mediators
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    ABSTRACT: Leukotriene A4 (LTA4, 5S-trans-5,6-oxido-7,9-trans-11,14-cis-eicosatetraenoic acid) hydrolase (LTA4H)/aminopeptidase is a bifunctional zinc metalloenzyme that catalyzes the final and rate-limiting step in the biosynthesis of leukotriene B4 (LTB4, 5S,12R-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid), a classical chemoattractant and immune modulating lipid mediator. Two chemical features are key to the bioactivity of LTB4, namely, the chirality of the 12R-hydroxyl group and the cis-trans-trans geometry of the conjugated triene structure. From the crystal structure of LTA4H, a hydrophilic patch composed of Gln-134, Tyr-267, and Asp-375 was identified in a narrow and otherwise hydrophobic pocket, believed to bind LTA4. In addition, Asp-375 belongs to peptide K21, a previously characterized 21-residue active site-peptide to which LTA4 binds during suicide inactivation. In the present report we used site-directed mutagenesis and x-ray crystallography to show that Asp-375, but none of the other candidate residues, is specifically required for the epoxide hydrolase activity of LTA4H. Thus, mutation of Asp-375 leads to a selective loss of the enzyme's ability to generate LTB4 whereas the aminopeptidase activity is preserved. We propose that Asp-375, possibly assisted by Gln-134, acts as a critical determinant for the stereoselective introduction of the 12R-hydroxyl group and thus the biological activity of LTB4.
    Full-text · Article · May 2002 · Proceedings of the National Academy of Sciences
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    ABSTRACT: Leukotriene A(4) hydrolase/aminopeptidase is a bifunctional zinc metalloenzyme that converts the fatty acid epoxide leukotriene A(4) into leukotriene B(4), a potent chemoattractant and immune-modulating lipid mediator. Recently, the structure of leukotriene A(4) hydrolase revealed that Glu-271, which belongs to a conserved GXMEN motif in the M1 family of zinc peptidases, and Gln-136 are located at the active site. Here we report that mutagenetic replacements of Glu-271, but not Gln-136, abrogate both catalytic activities of leukotriene A(4) hydrolase. Furthermore, the 2.1 A crystal structure of [E271Q]leukotriene A(4) hydrolase revealed minimal conformational changes that could not explain the loss of enzyme function. We propose that the carboxylate of Glu-271 participates in an acid-induced opening of the epoxide moiety of leukotriene A(4) and formation of a carbocation intermediate. Moreover, Glu-271 appears to act as an N-terminal recognition site and may potentially stabilize the transition-state during turnover of peptides, a property that most likely pertains to all members of the M1 family of zinc aminopeptidases. Hence, Glu-271 is a unique example of an amino acid, which has dual and separate functions in two different catalytic reactions, involving lipid and peptide substrates, respectively.
    No preview · Article · Feb 2002 · Journal of Biological Chemistry

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Publication Stats

149 Citations
23.57 Total Impact Points


  • 2004
    • Lund University
      Lund, Skåne, Sweden
  • 2002
    • Karolinska Institutet
      • Department of Medical Biochemistry and Biophysics
      Solna, Stockholm, Sweden
    • Stockholm University
      • Department of Biochemistry and Biophysics
      Tukholma, Stockholm, Sweden