The crystal structure of triacylglycerol lipase from <i>Pseudomonas glumae</i> reveals a partially redundant catalytic aspartate

Noble, M.E.M.; Cleasby, Anne; Johnson, L.N.; Egmond, Maarten R.; Frenken, Leon

doi:10.1016/0014-5793(93)80310-q

Cited by 276 publications

(168 citation statements)

References 21 publications

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“…An extensive search of the PDB shows that this motif is not characteristic for magnesium binding, but rather for calcium binding. Similar loops bind Ca 2+ cations in different bacterial lipases, such as lipases from Pseudomonas glumae (formerly Chromobacterium viscosum) (Noble et al 1993;Lang et al 1996) and Burkholderia cepacia (formerly Pseudomonas cepacia) (Shrag et al 1997;Luić et al 2001). The lipases are not the only enzymes that contain such a metal binding motif; it is also observed in human DNA polymerase b (Pelletier and Sawaya 1996).…”

Section: Metal Bindingmentioning

confidence: 99%

Crystal structures of TM0549 and NE1324—two orthologs of E. coli AHAS isozyme III small regulatory subunit

et al. 2007

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Crystal structures of two orthologs of the regulatory subunit of acetohydroxyacid synthase III (AHAS, EC 2.2.1.6) from Thermotoga maritima (TM0549) and Nitrosomonas europea (NE1324) were determined by single-wavelength anomalous diffraction methods with the use of selenomethionine derivatives at 2.3 Å and 2.5 Å , respectively. TM0549 and NE1324 share the same fold, and in both proteins the polypeptide chain contains two separate domains of a similar size. Each protein contains a C-terminal domain with ferredoxin-type fold and an N-terminal ACT domain, of which the latter is characteristic for several proteins involved in amino acid metabolism. The ferredoxin domain is stabilized by a calcium ion in the crystal structure of NE1324 and by a Mg(H 2 O) 6 2+ ion in TM0549. Both TM0549 and NE1324 form dimeric assemblies in the crystal lattice.Keywords: acetohydroxyacid synthase; actolactate synthase; regulatory subunit; ACT domain; AHAS; protein refolding Acetohydroxyacid synthase (AHAS, EC 2.2.1.6) catalyzes two physiologically significant reactions in the synthesis of isoleucine, valine, and leucine. In the first reaction, which is an initial step in the synthesis of isoleucine, 2-aceto-2-hydroxy butyrate is produced by condensation of 2-ketobutyrate with pyruvate. In the second reaction, 2-acetolactate is synthesized from two pyruvate molecules, and this provides substrates for synthesis of valine and leucine (Umbarger 1978(Umbarger , 1987Chipman et al. 1998). This pathway of branched-chain amino acid biosynthesis is characteristic for bacteria, fungi, algae, and higher plants, but not for animals. Accordingly, AHAS inhibitors have been developed as herbicides which have found broad application (Short and Colborn 1999). The inhibitors of branched-chain amino acids synthesis are also being tested as potential antituberculosis agents (Grandoni et al. 1998;Zohar et al. 2003;Choi et al. 2005).Three different FAD-dependent AHAS isozymes (I, II, and III) are found in enterobacteria (e.g., Escherichia ), but most other organisms from the bacteria encode only a single AHAS enzyme, similar to isozyme III from E. coli. The acetohydroxyacid synthases are multimeric proteins, and most frequently their biological unit is composed of two catalytic subunits (CSU) and two small regulatory subunits (SSU). In the absence of the SSU subunit, the CSU dimer is unstable (Vyazmensky et al. 1996), suggesting that in the holoenzyme the AHAS dimer is stabilized by a SSU dimer. The large catalytic subunits also show very weak activity without their associated regulatory subunits (Weinstock et al. 1992;Pang and Duggleby 1999). The E. coli AHAS enzyme can be reconstituted with SSU subunits from other organisms (Porat et al. 2004), and the reconstituted enzymes form stable heterotetramers. The properly associated holoenzymes show full catalytic activity, and are also susceptible to valine inhibition.Previous mutagenesis studies (Mendel et al. 2001;Kaplun et al. 2006) revealed that the valine binding sites are located at the dimerizatio...

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Section: Metal Bindingmentioning

confidence: 99%

Crystal structures of TM0549 and NE1324—two orthologs of E. coli AHAS isozyme III small regulatory subunit

et al. 2007

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“…In the lipases, lid opening uncovering the catalytic site is a key feature of interfacial activation; however, the lid domain may be formed by one or more helices or surface loops that differ not only in length and sequence, but also in location relative to the ␣/␤-hydrolase core and the active site (44 -49). In several ␣/␤-hydrolase proteins, the domain located between strands ␤ 6 and ␤ 7 is quite independent of the ␣/␤-hydrolase core and can accommodate large insertions such as a regulatory module (50), a putative helical lid (45), or a capping domain for the active site (51), without perturbing the core structure. The flexible short ⍀ loop Cys 257 -Cys 272 , which is also located between strands ␤ 6 and ␤ 7 of mAChE and protrudes to the surface of the molecule not far from the gorge entrance (Fig.…”

Section: Significance Of the Structurementioning

confidence: 99%

Crystal Structure of Mouse Acetylcholinesterase

Bourne¹,

Taylor²,

Bougis³

et al. 1999

Journal of Biological Chemistry

129

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The crystal structure of mouse acetylcholinesterase at 2.9-Å resolution reveals a tetrameric assembly of subunits with an antiparallel alignment of two canonical homodimers assembled through four-helix bundles. In the tetramer, a short ⍀ loop, composed of a cluster of hydrophobic residues conserved in mammalian acetylcholinesterases along with flanking ␣-helices, associates with the peripheral anionic site of the facing subunit and sterically occludes the entrance of the gorge leading to the active center. The inverse loop-peripheral site interaction occurs within the second pair of subunits, but the peripheral sites on the two loop-donor subunits remain freely accessible to the solvent. The position and complementarity of the peripheral site-occluding loop mimic the characteristics of the central loop of the peptidic inhibitor fasciculin bound to mouse acetylcholinesterase. Tetrameric forms of cholinesterases are widely distributed in nature and predominate in mammalian brain. This structure reveals a likely mode of subunit arrangement and suggests that the peripheral site, located near the rim of the gorge, is a site for association of neighboring subunits or heterologous proteins with interactive surface loops.

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“…A proton is then 56 transferred from the triad residues to the substrate hydroxyl group resulting in the cleavage of 57 the ester bond between the fatty acid and glycerol backbone. The intermediate fatty ester is 58 then attacked by water to regenerate the catalytic triad and fatty acid (Reis et al, 2009 (Arpigny & Jaeger, 1999;Bourne et al, 1994;Derewenda 62 et al, 1992;Jaeger & Reetz, 1998;Noble et al, 1993;Roussel et al, 1999;Schrag & Cygler, 63 1997;van Pouderoyen et al, 2001). Since lipase enzymes catalyze reactions at the interface 64 of water and neutral water-insoluble ester substrates, the catalytic triad that is buried in the 65 structure must surface in order to access the substrate (Cherukuvada et al, 2005;Reis et al, 66 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 5 played a role in the breakdown of triacylglycerol molecules in palm oil, and this breakdown of 93 oil provided diacylglyerol, monoacylglycerol, and free fatty acids for emulsification of palm 94 oil remaining in the culture (Brigham et al, 2010).…”

mentioning

confidence: 99%

Characterization of an extracellular lipase and its chaperone from Ralstonia eutropha H16

Brigham

Rha

et al. 2012

Appl Microbiol Biotechnol

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The crystal structure of triacylglycerol lipase from Pseudomonas glumae reveals a partially redundant catalytic aspartate

Cited by 276 publications

References 21 publications

Crystal structures of TM0549 and NE1324—two orthologs of E. coli AHAS isozyme III small regulatory subunit

Crystal structures of TM0549 and NE1324—two orthologs of E. coli AHAS isozyme III small regulatory subunit

Crystal Structure of Mouse Acetylcholinesterase

Characterization of an extracellular lipase and its chaperone from Ralstonia eutropha H16

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