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Title: Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol

Abstract

In this paper, we report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. Finally, in the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

Authors:
 [1];  [1];  [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Horsholm (Denmark)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); Defense Advanced Research Projects Agency (DARPA) (United States)
OSTI Identifier:
1393096
DOE Contract Number:  
AC02-05CH11231; HR001134783
Resource Type:
Journal Article
Journal Name:
ACS Synthetic Biology
Additional Journal Information:
Journal Volume: 5; Journal Issue: 12; Journal ID: ISSN 2161-5063
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; acetone carboxylase; biodegradation; bioengineering; carbon catabolism pathway; sarin; synthetic biology

Citation Formats

Brown, Margaret E., Mukhopadhyay, Aindrila, and Keasling, Jay D. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol. United States: N. p., 2016. Web. doi:10.1021/acssynbio.6b00115.
Brown, Margaret E., Mukhopadhyay, Aindrila, & Keasling, Jay D. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol. United States. doi:10.1021/acssynbio.6b00115.
Brown, Margaret E., Mukhopadhyay, Aindrila, and Keasling, Jay D. Tue . "Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol". United States. doi:10.1021/acssynbio.6b00115.
@article{osti_1393096,
title = {Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol},
author = {Brown, Margaret E. and Mukhopadhyay, Aindrila and Keasling, Jay D.},
abstractNote = {In this paper, we report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. Finally, in the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.},
doi = {10.1021/acssynbio.6b00115},
journal = {ACS Synthetic Biology},
issn = {2161-5063},
number = 12,
volume = 5,
place = {United States},
year = {2016},
month = {7}
}