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dc.contributor.authorPinakoulaki, Eftychiaen
dc.contributor.authorKoutsoupakis, Constantinosen
dc.contributor.authorSawai, H.en
dc.contributor.authorPavlou, A.en
dc.contributor.authorKato, Y.en
dc.contributor.authorAsano, Y.en
dc.contributor.authorAono, S.en
dc.creatorPinakoulaki, Eftychiaen
dc.creatorKoutsoupakis, Constantinosen
dc.creatorSawai, H.en
dc.creatorPavlou, A.en
dc.creatorKato, Y.en
dc.creatorAsano, Y.en
dc.creatorAono, S.en
dc.description.abstractFourier transform infrared (FTIR) spectra, "light" minus "dark" difference FTIR spectra, and time-resolved step-scan (TRS 2) FTIR spectra are reported for carbonmonoxy aldoxime dehydratase. Two C-O modes of heme at 1945 and 1964 cm-1 have been identified and remained unchanged in H2O/D2O exchange and in the pH 5.6-8.5 range, suggesting the presence of two conformations at the active site. The observed C-O frequencies are 5 and 16 cm-1 lower and higher, respectively, than that obtained previously (Oinuma, K.-I.en
dc.description.abstractet al. FEBS Lett.2004, 568, 44-48). We suggest that the strength of the Fe-His bond and the neutralization of the negatively charged propionate groups modulate the ν(Fe-CO)/ν(CO) back-bonding correlation. The "light" minus "dark" difference FTIR spectra indicate that the heme propionates are in both the protonated and deprotonated forms, and the photolyzed CO becomes trapped within a ligand docking site (ν(CO) = 2138 cm-1). The TRS2-FTIR spectra show that the rate of recombination of CO to the heme is k1945 cm-1 = 126 ± 20 s -1 and k1964 cm-1 = 122 ± 20 s -1 at pH 5.6, and k1945 cm-1 = 148 ± 30 s-1 and k1964 cm-1 = 158 ± 32 s -1 at pH 8.5. The rate of decay of the heme propionate vibrations is on a time scale coincident with the rate of rebinding, suggesting that there is a coupling between ligation dynamics in the distal heme environment and the environment sensed by the heme propionates. The implications of these results with respect to the proximal His-Fe heme environment including the propionates and the positively charged or proton-donating residues in the distal pocket which are crucial for the synthesis of nitriles are discussed. © 2011 American Chemical Society.en
dc.sourceJournal of Physical Chemistry Ben
dc.subjectVibrations (mechanical)en
dc.subjectVolatile fatty acidsen
dc.subjectFT-IR spectrumen
dc.subjectFourier transformsen
dc.subjectActive siteen
dc.subjectFourier transform infrareden
dc.subjectAldoxime dehydrataseen
dc.subjectDeprotonated formen
dc.subjectDistal pocketen
dc.subjectHeme propionatesen
dc.subjectLigand dockingen
dc.subjectPositively chargeden
dc.subjectRate of recombinationen
dc.subjectTriple bondsen
dc.titleAldoxime dehydratase: Probing the heme environment involved in the synthesis of the carbon-nitrogen triple bonden
dc.description.endingpage13018 Σχολή Θετικών και Εφαρμοσμένων Επιστημών / Faculty of Pure and Applied SciencesΤμήμα Χημείας / Department of Chemistry
dc.description.notes<p>Cited By :7</p>en
dc.source.abbreviationJ Phys Chem Ben
dc.contributor.orcidPinakoulaki, Eftychia [0000-0003-3320-6112]

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