Reverse Spin-Crossover and High-Pressure Kinetics of the HemeIron Center Relevant for the Operation of HemeProteins under Deep-Sea Conditions

By design of a heme model complex with a binding pocket of appropriate size and flexibility, and by elucidating its kinetics and thermodynamics under elevated pressures, some of the pressure effects are demonstrated relevant for operation of heme-proteins under deep-sea conditions. Opposite from cla...

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Bibliographic Details
Published in:Angewandte Chemie 2014-10, Vol.126 (43), p.11636-11641
Main Authors: Troeppner, Oliver, Lippert, Rainer, Shubina, Tatyana E, Zahl, Achim, Jux, Norbert, Ivanovic-Burmazovic, Ivana
Format: Article
Language:eng ; ger
Subjects:
Binding
Chemistry
Criteria
Deceleration
Elevated
Flexibility
Holes
Pocket
Reaction kinetics
Transformations
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Summary:By design of a heme model complex with a binding pocket of appropriate size and flexibility, and by elucidating its kinetics and thermodynamics under elevated pressures, some of the pressure effects are demonstrated relevant for operation of heme-proteins under deep-sea conditions. Opposite from classical paradigms of the spin-crossover and reaction kinetics, a pressure increase can cause deceleration of the small-molecule binding to the vacant coordination site of the heme-center in a confined space and stabilize a high-spin state of its Fecenter. This reverse high-pressure behavior can be achieved only if the volume changes related to the conformational transformation of the cavity can offset the volume changes caused by the substrate binding. It is speculated that based on these criteria nature could make a selection of structures of hemepockets that assist in reducing metabolic activity and enzymatic side reactions under extreme pressure conditions.Original Abstract: Hochdruckchemie: Der Einfluss einer raeumlich beschraenkten Umgebung auf ein Haem-Eisenzentrum wurde untersucht (siehe Bild). Dieser Effekt spielt eine wichtige Rolle fuer die Adaption von Mikroorganismen an extreme Hochdruckbedingungen und fuer die Entwicklung von invers operierenden Spinschaltern.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201406954