3f9c

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Crystal structure of human plasma platelet activating factor acetylhydrolase covalently inhibited by diisopropylfluorophosphateCrystal structure of human plasma platelet activating factor acetylhydrolase covalently inhibited by diisopropylfluorophosphate

Structural highlights

3f9c is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Gene:PLA2G7, PAFAH (HUMAN)
Activity:1-alkyl-2-acetylglycerophosphocholine esterase, with EC number 3.1.1.47
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

[PAFA_HUMAN] Defects in PLA2G7 are the cause of platelet-activating factor acetylhydrolase deficiency (PAFAD) [MIM:614278]. An enzymatic deficiency that results in exacerbated bodily response to inflammatory agents. Asthmatic individuals affected by this condition may manifest severe respiratory symptoms.[1] [2] [3] [4] [5] Defects in PLA2G7 are a cause of susceptibility to asthma (ASTHMA) [MIM:600807]. The most common chronic disease affecting children and young adults. It is a complex genetic disorder with a heterogeneous phenotype, largely attributed to the interactions among many genes and between these genes and the environment. It is characterized by recurrent attacks of paroxysmal dyspnea, with weezing due to spasmodic contraction of the bronchi. Note=PLA2G7 variants can be a risk factor for the development of asthma and PLA2G7 may act as a modifier gene that modulates the severity of this disease.[6] Defects in PLA2G7 are a cause of susceptibility to atopic hypersensitivity (ATOPY) [MIM:147050]. A condition characterized by predisposition to develop hypersensitivity reactions. Atopic individuals can develop eczema, allergic rhinitis and allergic asthma.[7]

Function

[PAFA_HUMAN] Modulates the action of platelet-activating factor (PAF) by hydrolyzing the sn-2 ester bond to yield the biologically inactive lyso-PAF. Has a specificity for substrates with a short residue at the sn-2 position. It is inactive against long-chain phospholipids.

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

The enzyme group-VIIA phospholipase A2 (gVIIA-PLA2) is bound to lipoproteins in human blood and hydrolyzes the ester bond at the sn-2 position of phospholipid substrates with a short sn-2 chain. The enzyme belongs to a serine hydrolase superfamily of enzymes, which react with organophosphorus (OP) nerve agents. OPs ultimately exert their toxicity by inhibiting human acetycholinesterase at nerve synapses, but may additionally have detrimental effects through inhibition of other serine hydrolases. We have solved the crystal structures of gVIIA-PLA2 following inhibition with the OPs diisopropylfluorophosphate, sarin, soman and tabun. The sarin and soman complexes displayed a racemic mix of P(R) and P(S) stereoisomers at the P-chiral center. The tabun complex displayed only the P(R) stereoisomer in the crystal. In all cases, the crystal structures contained intact OP adducts that had not aged. Aging refers to a secondary process OP complexes can go through, which dealkylates the nerve agent adduct and results in a form that is highly resistant to either spontaneous or oxime-mediated reactivation. Non-aged OP complexes of the enzyme were corroborated by trypsin digest and matrix-assisted laser desorption ionization mass spectrometry of OP-enzyme complexes. The lack of stereoselectivity of sarin reaction was confirmed by gas chromatography/mass spectrometry using a chiral column to separate and quantitate the unbound stereoisomers of sarin following incubation with enzyme. The structural details and characterization of nascent reactivity of several toxic nerve agents is discussed with a long-term goal of developing gVIIA-PLA2 as a catalytic bioscavenger of OP nerve agents.

Crystal structures of human group-VIIA phospholipase A2 inhibited by organophosphorus nerve agents exhibit non-aged complexes.,Samanta U, Kirby SD, Srinivasan P, Cerasoli DM, Bahnson BJ Biochem Pharmacol. 2009 Aug 15;78(4):420-9. Epub 2009 Apr 24. PMID:19394314[8]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. ↑ Stafforini DM, Satoh K, Atkinson DL, Tjoelker LW, Eberhardt C, Yoshida H, Imaizumi T, Takamatsu S, Zimmerman GA, McIntyre TM, Gray PW, Prescott SM. Platelet-activating factor acetylhydrolase deficiency. A missense mutation near the active site of an anti-inflammatory phospholipase. J Clin Invest. 1996 Jun 15;97(12):2784-91. PMID:8675689 doi:10.1172/JCI118733
  2. ↑ Yamada Y, Yokota M. Loss of activity of plasma platelet-activating factor acetylhydrolase due to a novel Gln281-->Arg mutation. Biochem Biophys Res Commun. 1997 Jul 30;236(3):772-5. PMID:9245731 doi:S0006-291X(97)97047-9
  3. ↑ Hiramoto M, Yoshida H, Imaizumi T, Yoshimizu N, Satoh K. A mutation in plasma platelet-activating factor acetylhydrolase (Val279-->Phe) is a genetic risk factor for stroke. Stroke. 1997 Dec;28(12):2417-20. PMID:9412624
  4. ↑ Yamada Y, Ichihara S, Fujimura T, Yokota M. Identification of the G994--> T missense in exon 9 of the plasma platelet-activating factor acetylhydrolase gene as an independent risk factor for coronary artery disease in Japanese men. Metabolism. 1998 Feb;47(2):177-81. PMID:9472966
  5. ↑ Yoshida H, Imaizumi T, Fujimoto K, Itaya H, Hiramoto M, Yoshimizu N, Fukushi K, Satoh K. A mutation in plasma platelet-activating factor acetylhydrolase (Val279Phe) is a genetic risk factor for cerebral hemorrhage but not for hypertension. Thromb Haemost. 1998 Sep;80(3):372-5. PMID:9759612
  6. ↑ Kruse S, Mao XQ, Heinzmann A, Blattmann S, Roberts MH, Braun S, Gao PS, Forster J, Kuehr J, Hopkin JM, Shirakawa T, Deichmann KA. The Ile198Thr and Ala379Val variants of plasmatic PAF-acetylhydrolase impair catalytical activities and are associated with atopy and asthma. Am J Hum Genet. 2000 May;66(5):1522-30. Epub 2000 Mar 24. PMID:10733466 doi:S0002-9297(07)62982-6
  7. ↑ Kruse S, Mao XQ, Heinzmann A, Blattmann S, Roberts MH, Braun S, Gao PS, Forster J, Kuehr J, Hopkin JM, Shirakawa T, Deichmann KA. The Ile198Thr and Ala379Val variants of plasmatic PAF-acetylhydrolase impair catalytical activities and are associated with atopy and asthma. Am J Hum Genet. 2000 May;66(5):1522-30. Epub 2000 Mar 24. PMID:10733466 doi:S0002-9297(07)62982-6
  8. ↑ Samanta U, Kirby SD, Srinivasan P, Cerasoli DM, Bahnson BJ. Crystal structures of human group-VIIA phospholipase A2 inhibited by organophosphorus nerve agents exhibit non-aged complexes. Biochem Pharmacol. 2009 Aug 15;78(4):420-9. Epub 2009 Apr 24. PMID:19394314 doi:10.1016/j.bcp.2009.04.018

3f9c, resolution 2.30Å

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