1t6p: Difference between revisions
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[[Image: | ==Crystal Structure of Phenylalanine Ammonia Lyase from Rhodosporidium toruloides== | ||
<StructureSection load='1t6p' size='340' side='right' caption='[[1t6p]], [[Resolution|resolution]] 2.70Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1t6p]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Rhodosporidium_toruloides Rhodosporidium toruloides]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1T6P OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1T6P FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=175:3,5-DIHYDRO-5-METHYLIDENE-4H-IMIDAZOL-4-ON'>175</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1t6j|1t6j]]</td></tr> | |||
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">PAL ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=5286 Rhodosporidium toruloides])</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Lyase Lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.3.1.23, 4.3.1.24 and 4.3.1.25 4.3.1.23, 4.3.1.24 and 4.3.1.25] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1t6p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1t6p OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1t6p RCSB], [http://www.ebi.ac.uk/pdbsum/1t6p PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/t6/1t6p_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The first three-dimensional structure of phenylalanine ammonia lyase (PAL) has been determined at 2.1 A resolution for PAL from Rhodosporidium toruloides. The enzyme is structurally similar to the mechanistically related histidine ammonia lyase (HAL), with PAL having an additional approximately 160 residues extending from the common fold. We propose that catalysis (including lowering the pK(a) of nonacidic C3 of l-phenylalanine for an E1cb mechanism) is potentially governed by dipole moments of seven alpha helices associated with the PAL active site (six positive poles and one negative pole). Cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) resides atop the positive poles of three helices, for increasing its electrophilicity. The helix dipoles appear fully compatible with a model of phenylalanine docked in the active site of PAL having the first covalent bond formed between the amino group of substrate and the methylidene group of MIO: 12 highly conserved residues (near the N termini of helices for enhancing function) are poised to serve roles in substrate recognition, MIO activation, product separation, proton donation, or polarizing electrons from the phenyl ring of substrate for activation of C3; and a highly conserved His residue (near the C terminus of the one helix that directs its negative pole toward the active site to increase the residue's basicity) is positioned to act as a general base, abstracting the pro-S hydrogen from C3 of substrate. A similar mechanism is proposed for HAL, which has a similar disposition of seven alpha helices and similar active-site residues. The helix dipoles appear incompatible with a proposed mechanism that invokes a carbocation intermediate. | |||
Crystal structure of phenylalanine ammonia lyase: multiple helix dipoles implicated in catalysis.,Calabrese JC, Jordan DB, Boodhoo A, Sariaslani S, Vannelli T Biochemistry. 2004 Sep 14;43(36):11403-16. PMID:15350127<ref>PMID:15350127</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Lyase]] | [[Category: Lyase]] | ||
[[Category: Rhodosporidium toruloides]] | [[Category: Rhodosporidium toruloides]] | ||
Revision as of 21:39, 29 September 2014
Crystal Structure of Phenylalanine Ammonia Lyase from Rhodosporidium toruloidesCrystal Structure of Phenylalanine Ammonia Lyase from Rhodosporidium toruloides
Structural highlights
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 PubMedThe first three-dimensional structure of phenylalanine ammonia lyase (PAL) has been determined at 2.1 A resolution for PAL from Rhodosporidium toruloides. The enzyme is structurally similar to the mechanistically related histidine ammonia lyase (HAL), with PAL having an additional approximately 160 residues extending from the common fold. We propose that catalysis (including lowering the pK(a) of nonacidic C3 of l-phenylalanine for an E1cb mechanism) is potentially governed by dipole moments of seven alpha helices associated with the PAL active site (six positive poles and one negative pole). Cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) resides atop the positive poles of three helices, for increasing its electrophilicity. The helix dipoles appear fully compatible with a model of phenylalanine docked in the active site of PAL having the first covalent bond formed between the amino group of substrate and the methylidene group of MIO: 12 highly conserved residues (near the N termini of helices for enhancing function) are poised to serve roles in substrate recognition, MIO activation, product separation, proton donation, or polarizing electrons from the phenyl ring of substrate for activation of C3; and a highly conserved His residue (near the C terminus of the one helix that directs its negative pole toward the active site to increase the residue's basicity) is positioned to act as a general base, abstracting the pro-S hydrogen from C3 of substrate. A similar mechanism is proposed for HAL, which has a similar disposition of seven alpha helices and similar active-site residues. The helix dipoles appear incompatible with a proposed mechanism that invokes a carbocation intermediate. Crystal structure of phenylalanine ammonia lyase: multiple helix dipoles implicated in catalysis.,Calabrese JC, Jordan DB, Boodhoo A, Sariaslani S, Vannelli T Biochemistry. 2004 Sep 14;43(36):11403-16. PMID:15350127[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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