title: Distinct structural and redox properties of the heme active site in bacterial dye decolorizing peroxidase-type peroxidases from two subfamilies: resonance Raman and electrochemical study.
abstract: Spectroscopic data of dye decolorizing peroxidases (DyPs) from Bacillus subtilis (BsDyP), an A subfamily member, and Pseudomonas putida (PpDyP), a B subfamily enzyme, reveal distinct heme coordination patterns of the respective active sites. In solution, both enzymes show a heterogeneous spin population, with the six-coordinated low-spin state being the most populated in the former and the five-coordinated quantum mechanically mixed-spin state in the latter. We ascribe the poor catalytic activity of BsDyP to the presence of a catalytically incompetent six-coordinated low-spin population. The spin populations of the two DyPs are sensitively dependent on the pH, temperature, and physical, i.e., solution versus crystal versus immobilized, state of the enzymes. We observe a redox potential for the Fe(2+)/Fe(3+) couple in BsDyP (-40 mV) at pH 7.6 substantially more positive than those reported for the majority of other peroxidases, including PpDyP (-260 mV). Furthermore, we evaluate the potential of the studied enzymes for biotechnological applications on the basis of electrochemical and spectroelectrochemical data.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da Republica, 2780-157 Oeiras, Portugal.
authors.forename: Murat
authors.initials: M
authors.lastname: Sezer
authors.forename: Ana
authors.initials: A
authors.lastname: Santos
authors.forename: Patrycja
authors.initials: P
authors.lastname: Kielb
authors.forename: Tiago
authors.initials: T
authors.lastname: Pinto
authors.forename: Ligia O
authors.initials: LO
authors.lastname: Martins
authors.forename: Smilja
authors.initials: S
authors.lastname: Todorovic
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000378:metabolism*; D002384:Catalysis; D020134:Catalytic Domain; D003116:Color; D055664:Electrochemical Techniques; D006418:Heme / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism*; D013059:Spectrum Analysis, Raman; D013696:Temperature
chemical_list: D006418:Heme; D010544:Peroxidases