| Structural highlights
1sqm is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , |
| Related: | 1gw6, 1h19, 1hs6 |
| Gene: | LTA4H, LTA4 (HUMAN) |
| Activity: | Leukotriene-A(4) hydrolase, with EC number 3.3.2.6 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum |
Function
[LKHA4_HUMAN] Epoxide hydrolase that catalyzes the final step in the biosynthesis of the proinflammatory mediator leukotriene B4. Has also aminopeptidase activity.[1] [2] [3] [4] [5] [6] [7]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Leukotriene (LT) A(4) hydrolase is a bifunctional zinc metalloenzyme, which converts LTA(4) into the neutrophil chemoattractant LTB(4) and also exhibits an anion-dependent aminopeptidase activity. In the x-ray crystal structure of LTA(4) hydrolase, Arg(563) and Lys(565) are found at the entrance of the active center. Here we report that replacement of Arg(563), but not Lys(565), leads to complete abrogation of the epoxide hydrolase activity. However, mutations of Arg(563) do not seem to affect substrate binding strength, because values of K(i) for LTA(4) are almost identical for wild type and (R563K)LTA(4) hydrolase. These results are supported by the 2.3-A crystal structure of (R563A)LTA(4) hydrolase, which does not reveal structural changes that can explain the complete loss of enzyme function. For the aminopeptidase reaction, mutations of Arg(563) reduce the catalytic activity (V(max) = 0.3-20%), whereas mutations of Lys(565) have limited effect on catalysis (V(max) = 58-108%). However, in (K565A)- and (K565M)LTA(4) hydrolase, i.e. mutants lacking a positive charge, values of the Michaelis constant for alanine-p-nitroanilide increase significantly (K(m) = 480-640%). Together, our data indicate that Arg(563) 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, Arg(563) and Lys(565) seem to cooperate to provide sufficient binding strength and productive alignment of the substrate. In conclusion, Arg(563) and Lys(565) possess distinct roles as carboxylate recognition sites for two chemically different substrates, each of which is turned over in separate enzymatic reactions catalyzed by LTA(4) hydrolase.
Leukotriene A4 hydrolase: identification of a common carboxylate recognition site for the epoxide hydrolase and aminopeptidase substrates.,Rudberg PC, Tholander F, Andberg M, Thunnissen MM, Haeggstrom JZ J Biol Chem. 2004 Jun 25;279(26):27376-82. Epub 2004 Apr 12. PMID:15078870[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Odlander B, Claesson HE, Bergman T, Radmark O, Jornvall H, Haeggstrom JZ. Leukotriene A4 hydrolase in the human B-lymphocytic cell line Raji: indications of catalytically divergent forms of the enzyme. Arch Biochem Biophys. 1991 May 15;287(1):167-74. PMID:1897988
- ↑ Toh H, Minami M, Shimizu T. Molecular evolution and zinc ion binding motif of leukotriene A4 hydrolase. Biochem Biophys Res Commun. 1990 Aug 31;171(1):216-21. PMID:1975494
- ↑ Haeggstrom JZ, Wetterholm A, Shapiro R, Vallee BL, Samuelsson B. Leukotriene A4 hydrolase: a zinc metalloenzyme. Biochem Biophys Res Commun. 1990 Nov 15;172(3):965-70. PMID:2244921
- ↑ Thunnissen MM, Andersson B, Samuelsson B, Wong CH, Haeggstrom JZ. Crystal structures of leukotriene A4 hydrolase in complex with captopril and two competitive tight-binding inhibitors. FASEB J. 2002 Oct;16(12):1648-50. Epub 2002 Aug 7. PMID:12207002 doi:10.1096/fj.01-1017fje
- ↑ Rudberg PC, Tholander F, Thunnissen MM, Samuelsson B, Haeggstrom JZ. Leukotriene A4 hydrolase: selective abrogation of leukotriene B4 formation by mutation of aspartic acid 375. Proc Natl Acad Sci U S A. 2002 Apr 2;99(7):4215-20. Epub 2002 Mar 26. PMID:11917124 doi:10.1073/pnas.072090099
- ↑ Rudberg PC, Tholander F, Andberg M, Thunnissen MM, Haeggstrom JZ. Leukotriene A4 hydrolase: identification of a common carboxylate recognition site for the epoxide hydrolase and aminopeptidase substrates. J Biol Chem. 2004 Jun 25;279(26):27376-82. Epub 2004 Apr 12. PMID:15078870 doi:10.1074/jbc.M401031200
- ↑ Tholander F, Muroya A, Roques BP, Fournie-Zaluski MC, Thunnissen MM, Haeggstrom JZ. Structure-based dissection of the active site chemistry of leukotriene A4 hydrolase: implications for M1 aminopeptidases and inhibitor design. Chem Biol. 2008 Sep 22;15(9):920-9. PMID:18804029 doi:10.1016/j.chembiol.2008.07.018
- ↑ Rudberg PC, Tholander F, Andberg M, Thunnissen MM, Haeggstrom JZ. Leukotriene A4 hydrolase: identification of a common carboxylate recognition site for the epoxide hydrolase and aminopeptidase substrates. J Biol Chem. 2004 Jun 25;279(26):27376-82. Epub 2004 Apr 12. PMID:15078870 doi:10.1074/jbc.M401031200
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