Photothermal studies of CO photodissociation from mixed valence Escherichia coli cytochrome bo3 Article

Mikšovská, J, Gennis, RB, Larsen, RW. (2005). Photothermal studies of CO photodissociation from mixed valence Escherichia coli cytochrome bo3 . FEBS LETTERS, 579(14), 3014-3018. 10.1016/j.febslet.2005.04.055

cited authors

  • Mikšovská, J; Gennis, RB; Larsen, RW

authors

abstract

  • Here, we report the volume and enthalpy changes accompanying CO photodissociation from the mixed valence form of cytochrome bo3 oxidase from Escherichia coli. The results of photoacoustic calorimetry indicate two kinetic phases with distinct volume and enthalpy changes accompanying CO photodissociation from heme o3 and its transfer to CuB. The first phase occurring on a timescale of <50 ns is characterized by a volume decrease of -1.3 ± 0.3 mL mol-1 and enthalpy change of 32 ± 1.6 kcal mol-1. Subsequently, a volume increase of 2.9 mL mol-1 with an enthalpy change of -5.3 ± 2.5 kcal mol -1 is observed with the lifetime of ∼250 ns (this phase has not been detected in previous optical studies). These volume and enthalpy changes differ from the volume and enthalpy changes observed for CO dissociation from fully reduced cytochrome bo3 oxidase indicating that the heme o 3/CuB active site dynamics are affected by the redox state of heme b. © 2005 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

publication date

  • June 6, 2005

published in

Digital Object Identifier (DOI)

start page

  • 3014

end page

  • 3018

volume

  • 579

issue

  • 14