1hde

<table><tr><td colspan='2'>[[1hde]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/"corynebacterium_autotrophicum"_baumgarten_et_al._1974 "corynebacterium autotrophicum" baumgarten et al. 1974]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HDE OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1HDE FirstGlance]. <br>

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Haloalkane_dehalogenase Haloalkane dehalogenase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.8.1.5 3.8.1.5] </span></td></tr>

[[https://www.uniprot.org/uniprot/DHLA_XANAU DHLA_XANAU]] Catalyzes hydrolytic cleavage of carbon-halogen bonds in halogenated aliphatic compounds, leading to the formation of the corresponding primary alcohols, halide ions and protons. Has a broad substrate specificity, which includes terminally mono- and di- chlorinated and brominated alkanes (up to C4 only). The highest activity was found with 1,2-dichloroethane, 1,3-dichloropropane, and 1,2-dibromoethane.

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== Publication Abstract from PubMed ==

Conversion of halogenated aliphatics by haloalkane dehalogenase proceeds via the formation of a covalent alkyl-enzyme intermediate which is subsequently hydrolyzed by water. In the wild type enzyme, the slowest step for both 1,2-dichloroethane and 1,2-dibromoethane conversion is a unimolecular enzyme isomerization preceding rapid halide dissociation. Phenylalanine 172 is located in a helix-loop-helix structure that covers the active site cavity of the enzyme, interacts with the C1 beta of 1,2-dichloroethane during catalysis, and could be involved in stabilization of this helix-loop-helix region of the cap domain of the enzyme. To obtain more information about the role of this residue in dehalogenase function, we performed a mutational analysis of position 172 and studied the kinetics and X-ray structure of the Phe172Trp enzyme. The Phe172Trp mutant had a 10-fold higher Kcat/Km for 1-chlorohexane and a 2-fold higher Kcat for 1,2-dibromoethane than the wild-type enzyme. The X-ray structure of the Phe172Trp enzyme showed a local conformational change in the helix-loop-helix region that covers the active site. This could explain the elevated activity for 1-chlorohexane of the Phe172Trp enzyme, since it allows this large substrate to bind more easily in the active site cavity. Pre-steady-state kinetic analysis showed that the increase in Kcat found for 1,2-dibromoethane conversion could be attributed to an increase in the rate of an enzyme isomerization step that preceeds halide release. The observed conformational difference between the helix-loop-helix structures of the wild-type enzyme and the faster mutant suggests that the isomerization required for halide release could be a conformational change that takes place in this region of the cap domain of the dehalogenase. It is proposed that Phe172 is involved in stabilization of the helix-loop-helix structure that covers the active site of the enzyme and creates a rigid hydrophobic cavity for small apolar halogenated alkanes.

Kinetic characterization and X-ray structure of a mutant of haloalkane dehalogenase with higher catalytic activity and modified substrate range.,Schanstra JP, Ridder IS, Heimeriks GJ, Rink R, Poelarends GJ, Kalk KH, Dijkstra BW, Janssen DB Biochemistry. 1996 Oct 8;35(40):13186-95. PMID:8855957<ref>PMID:8855957</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Corynebacterium autotrophicum baumgarten et al. 1974]]

[[Category: Haloalkane dehalogenase]]

[[Category: Dijkstra, B W]]

[[Category: Kalk, K H]]

[[Category: Ridder, I S]]

[[Category: Dehalogenase]]

[[Category: Hydrolase]]