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Title (Primary) Investigation of active site amino acid influence on carbon and chlorine isotope fractionation during reductive dechlorination
Author Phillips, E.; Bulka, O.; Picott, K.; Kümmel, S.; Edwards, E.; Nijenhuis, I.; Gehre, M.; Dworatzek, S.; Webb, J.; Sherwood Lollar, B.
Journal FEMS Microbiology Ecology
Year 2022
Department ISOBIO
Volume 98
Issue 8
Page From fiac072
Language englisch
Topic T7 Bioeconomy
Supplements https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/femsec/98/8/10.1093_femsec_fiac072/1/fiac072_supplemental_file.docx?Expires=1662724670&Signature=JtjJSeuCiQwKXAoHaCCpL9LZwYzHbT43G8goCNmoJxiAbYEnLzM16W-M91gNvun9n8EHNEFaUKNhAZs6zPDrOcN7SV3CC-el2kImnmqoMinbq~zzujxYQkRyrxvmBdETB96tqDSjsyOkA2GxYY2N6J7F6M1Pbw4Kj-hYNXC6noO569vSv8u0kCW8TlnWiKFjqEiJPW6V3qbOgqnI7-CB~ts9QsZlM8cQJhXfnHPqVdHJRfqixYstsVHPwy3OlH4TR1wTSM8FIL7cDxOltiPscwn9WbcL~H3omFSmWANKFECyguaNlxyIWRjKicQCSURh~xd0bxzS8NYm4GyBpKW2pA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA
Keywords Compound-specific isotope analysis; amino acid identity; reductive dehalogenases; biotransformation; chlorinated alkanes; reductive dechlorination
UFZ wide themes ProVIS;
Abstract Reductive dehalogenases (RDases) are corrinoid-dependent enzymes that reductively dehalogenate organohalides in respiratory processes. By comparing isotope effects in biotically-catalyzed reactions to reference experiments with abiotic corrinoid-catalysts, compound-specific isotope analysis (CSIA) has been shown to yield valuable insights into enzyme mechanisms and kinetics, including RDases. Here, we report isotopic fractionation (ε) during biotransformation of chloroform (CF) for carbon (εC = -1.52 ± 0.34‰) and chlorine (εCl = -1.84 ± 0.19‰), corresponding to a ΛC/Cl value of 1.13 ± 0.35. These results are highly suppressed compared to isotope effects observed both during CF biotransformation by another organism with a highly similar RDase (> 95% sequence identity) at the amino acid level, and to those observed during abiotic dehalogenation of CF. Amino acid differences occur at four locations within the two different RDases’ active sites, and this study examines whether these differences potentially affect the observed εC, εCl, and ΛC/Cl. Structural protein models approximating the locations of the residues elucidate possible controls on reaction mechanisms and/or substrate binding efficiency. These four locations are not conserved among other chloroalkane reducing RDases with high amino acid similarity (> 90%), suggesting that these locations may be important in determining isotope fractionation within this homologous group of RDases.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=26285
Phillips, E., Bulka, O., Picott, K., Kümmel, S., Edwards, E., Nijenhuis, I., Gehre, M., Dworatzek, S., Webb, J., Sherwood Lollar, B. (2022):
Investigation of active site amino acid influence on carbon and chlorine isotope fractionation during reductive dechlorination
FEMS Microbiol. Ecol. 98 (8), fiac072