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| | ==RebH with bound L-Trp== | | ==RebH with bound L-Trp== |
| - | <StructureSection load='2e4g' size='340' side='right' caption='[[2e4g]], [[Resolution|resolution]] 2.08Å' scene=''> | + | <StructureSection load='2e4g' size='340' side='right'caption='[[2e4g]], [[Resolution|resolution]] 2.08Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2e4g]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"nocardia_aerocolonigenes"_(shinobu_and_kawato_1960)_pridham_1970 "nocardia aerocolonigenes" (shinobu and kawato 1960) pridham 1970]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2E4G OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2E4G FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2e4g]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/"nocardia_aerocolonigenes"_(shinobu_and_kawato_1960)_pridham_1970 "nocardia aerocolonigenes" (shinobu and kawato 1960) pridham 1970]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2E4G OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2E4G FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=TRP:TRYPTOPHAN'>TRP</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=TRP:TRYPTOPHAN'>TRP</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">rebH ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=68170 "Nocardia aerocolonigenes" (Shinobu and Kawato 1960) Pridham 1970])</td></tr> | + | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">rebH ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=68170 "Nocardia aerocolonigenes" (Shinobu and Kawato 1960) Pridham 1970])</td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2e4g FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2e4g OCA], [http://pdbe.org/2e4g PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2e4g RCSB], [http://www.ebi.ac.uk/pdbsum/2e4g PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2e4g ProSAT]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2e4g FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2e4g OCA], [https://pdbe.org/2e4g PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2e4g RCSB], [https://www.ebi.ac.uk/pdbsum/2e4g PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2e4g ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/REBH_NOCAE REBH_NOCAE]] Involved in the biosynthesis of the indolocarbazole antitumor agent rebeccamycin. Catalyze the chlorination of tryptophan (Trp) at C7 position to yield 7-chlorotryptophan. The reaction between FADH2, Cl-, and O2 generates the powerful oxidant HOCl, which is presumed to carry out the chlorination reaction. The reaction of HOCl with the active site Lys-79 generates a lysine chloramine, which plays a key role in directing regiospecific chlorination of substrate in this important class of biosynthetic enzymes. It is also able to use bromide ions to generate monobrominated Trp.<ref>PMID:11983340</ref> <ref>PMID:15743914</ref> <ref>PMID:17260957</ref> | + | [[https://www.uniprot.org/uniprot/REBH_NOCAE REBH_NOCAE]] Involved in the biosynthesis of the indolocarbazole antitumor agent rebeccamycin. Catalyze the chlorination of tryptophan (Trp) at C7 position to yield 7-chlorotryptophan. The reaction between FADH2, Cl-, and O2 generates the powerful oxidant HOCl, which is presumed to carry out the chlorination reaction. The reaction of HOCl with the active site Lys-79 generates a lysine chloramine, which plays a key role in directing regiospecific chlorination of substrate in this important class of biosynthetic enzymes. It is also able to use bromide ions to generate monobrominated Trp.<ref>PMID:11983340</ref> <ref>PMID:15743914</ref> <ref>PMID:17260957</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
| | Check<jmol> | | Check<jmol> |
| | <jmolCheckbox> | | <jmolCheckbox> |
| - | <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/e4/2e4g_consurf.spt"</scriptWhenChecked> | + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/e4/2e4g_consurf.spt"</scriptWhenChecked> |
| | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> |
| | <text>to colour the structure by Evolutionary Conservation</text> | | <text>to colour the structure by Evolutionary Conservation</text> |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| | + | [[Category: Large Structures]] |
| | [[Category: Blasiak, L C]] | | [[Category: Blasiak, L C]] |
| | [[Category: Drennan, C L]] | | [[Category: Drennan, C L]] |
| Structural highlights
Function
[REBH_NOCAE] Involved in the biosynthesis of the indolocarbazole antitumor agent rebeccamycin. Catalyze the chlorination of tryptophan (Trp) at C7 position to yield 7-chlorotryptophan. The reaction between FADH2, Cl-, and O2 generates the powerful oxidant HOCl, which is presumed to carry out the chlorination reaction. The reaction of HOCl with the active site Lys-79 generates a lysine chloramine, which plays a key role in directing regiospecific chlorination of substrate in this important class of biosynthetic enzymes. It is also able to use bromide ions to generate monobrominated Trp.[1] [2] [3]
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 flavin-dependent halogenase RebH catalyzes the formation of 7-chlorotryptophan as the initial step in the biosynthesis of antitumor agent rebeccamycin. The reaction of FADH2, Cl-, and O2 in the active site generates the powerful oxidant HOCl, which was presumed to carry out the chlorination reaction. Herein, we demonstrate the formation of a long-lived chlorinating intermediate (t1/2 = 63 h at 4 degrees C) when RebH, FADH2, Cl-, and O2 react in the absence of substrate tryptophan. This intermediate remained on the enzyme after removal of FAD and transferred chlorine to tryptophan with kinetically competent rates. The identity of this intermediate is suggested by the X-ray crystal structure of RebH, which revealed an active site Lys79 located in a central position between flavin and tryptophan binding sites and just 4.1 A above C7 of tryptophan. The chlorinating species is proposed to be a Lys-epsilonNH-Cl (lysine chloramine) from reaction of enzyme-generated HOCl with the active site Lys79. This covalent enzyme chloramine likely plays a key role in directing regiospecific chlorination of substrate in this important class of biosynthetic enzymes.
Chlorination by a long-lived intermediate in the mechanism of flavin-dependent halogenases.,Yeh E, Blasiak LC, Koglin A, Drennan CL, Walsh CT Biochemistry. 2007 Feb 6;46(5):1284-92. PMID:17260957[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Sanchez C, Butovich IA, Brana AF, Rohr J, Mendez C, Salas JA. The biosynthetic gene cluster for the antitumor rebeccamycin: characterization and generation of indolocarbazole derivatives. Chem Biol. 2002 Apr;9(4):519-31. PMID:11983340
- ↑ Yeh E, Garneau S, Walsh CT. Robust in vitro activity of RebF and RebH, a two-component reductase/halogenase, generating 7-chlorotryptophan during rebeccamycin biosynthesis. Proc Natl Acad Sci U S A. 2005 Mar 15;102(11):3960-5. Epub 2005 Mar 2. PMID:15743914 doi:http://dx.doi.org/10.1073/pnas.0500755102
- ↑ Yeh E, Blasiak LC, Koglin A, Drennan CL, Walsh CT. Chlorination by a long-lived intermediate in the mechanism of flavin-dependent halogenases. Biochemistry. 2007 Feb 6;46(5):1284-92. PMID:17260957 doi:10.1021/bi0621213
- ↑ Yeh E, Blasiak LC, Koglin A, Drennan CL, Walsh CT. Chlorination by a long-lived intermediate in the mechanism of flavin-dependent halogenases. Biochemistry. 2007 Feb 6;46(5):1284-92. PMID:17260957 doi:10.1021/bi0621213
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