PuSH - Publication Server of Helmholtz Zentrum München

Meyer, A.H. ; Penning, H. ; Elsner, M.

C and N isotope fractionation suggests similar mechanisms of microbial atrazine transformation despite involvement of different enzymes (AtzA and TrzN).

Environ. Sci. Technol. 43, 8079-8085 (2009)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Transformation of atrazine to hydroxyatrazine in the environment may be underestimated by current assessment schemes since immobilization and further transformation of the metabolite can render parent-to-daughter compound ratios unreliable. This study reports significant C and N isotope fractionation of atrazine in transformation to hydroxyatrazine by Chelatobacter heintzii, Pseudomonas sp. ADP, and Arthrobacter aurescens M highlighting an alternative approach to detecting this natural transformation pathway. Indistinguishable dual isotope slopes Delta (= delta N-15/delta C-13 approximate to epsilon(N)/epsilon(C)) for Chelatobacter heintzii (-0.65 +/- 0.08) and Arthrobacter aurescens TC1 (-0.61 +/- 0.02) suggest the same biochemical transformation mechanism despite different hydrolyzing enzymes (AtzA versus TrzN). With Pseudomonas sp. ADP (also AtzA) significantly smaller fractionation indicates masking effects by steps prior to enzyme catalysis, while a distinguishable Delta = -0.32 +/- 0.06 suggests that some of these steps showed slight isotope fractionation. Abiotic reference experiments reproduced the pattern of biotic transformation at pH 3 (enrichment of C-13, depletion of N-15 in atrazine), but showed enrichment of both C-13 and N-15 at pH 12. This indicates that the organisms activated atrazine by a similar Lewis acid complexation (e.g., with H+) prior to nucleophilic aromatic substitution, giving the first detailed mechanistic insight into this important enzymatic reaction.
Altmetric
Additional Metrics?
[➜Log in]
Edit extra informations Login
Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords arthrobacter-aurescens tc1; catabolism genes; pseudomonas sp; s-triazines; carbon; hydroxyatrazine; biodegradation; degradation; pathways; soil
ISSN (print) / ISBN 0013-936X
e-ISSN 1520-5851
Journal Environmental Science & Technology
Quellenangaben Volume: 43, Issue: 21, Pages: 8079-8085 Article Number: , Supplement: ,
Publisher ACS
Publishing Place Washington, DC
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Groundwater Ecology (IGOE)