title: Novel metal-binding site of Pseudomonas reinekei MT1 trans-dienelactone hydrolase.
abstract: Pseudomonasreinekei MT1 is capable of growing on 4- and 5-chlorosalicylate as the sole carbon source involving a pathway with trans-dienelactone hydrolase as the key enzyme. This enzyme transforms 4-chloromuconolactone to maleylacetate and thereby avoids the spontaneous formation of toxic protoanemonin. trans-Dienelactone hydrolase is a Zn(2+)-dependent hydrolase where activity can be modulated by the exchange of Zn(2+) by Mn(2+) in at least two of the three metal-binding sites. Site directed variants of conserved residues of the Q(101)XXXQ(105)XD(107)XXXH(111) motif and of H281 and E294 exhibit a two order of magnitude decrease in activity and a strong decrease in metal-binding capability. As none of the variants exhibited a change in secondary structure, the analyzed amino acid residues can be assumed to be involved in metal binding, forming a novel trinuclear metal-binding motif.
authors.affiliation: Division of Microbial Pathogenesis, HZI - Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
authors.forename: Macarena
authors.initials: M
authors.lastname: Marín
authors.forename: Dietmar H
authors.initials: DH
authors.lastname: Pieper
mesh_terms: D001665:Binding Sites; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002396:Catechols / Q000378:metabolism; D002413:Cations, Divalent; D008345:Manganese / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011549:Pseudomonas / Q000201:enzymology*; D015032:Zinc / Q000378:metabolism*
chemical_list: D002396:Catechols; D002413:Cations, Divalent; D008345:Manganese; D002265:Carboxylic Ester Hydrolases; C046130:carboxymethylenebutenolidase; C038861:4-chlorocatechol; D015032:Zinc