Open Access

Erratum to: Production of hydroxycinnamoyl anthranilates from glucose in Escherichia coli

  • Aymerick Eudes1, 2,
  • Darmawi Juminaga1, 3,
  • Edward EK Baidoo1,
  • F William Collins4,
  • Jay D Keasling1, 2, 3, 5 and
  • Dominique Loqué1, 2Email author
Contributed equally
Microbial Cell Factories201413:8

https://doi.org/10.1186/1475-2859-13-8

Received: 10 January 2014

Accepted: 10 January 2014

Published: 15 January 2014

The original article was published in Microbial Cell Factories 2013 12:62

Following publication of this work [1] we noticed that an outdated protocol for metabolite separation has been accidentally described in “LC-MS analysis of cinnamoyl anthranilates and precursors” paragraph of the materials and methods section. The correct protocol is shown below.

LC-MS analysis of cinnamoyl anthranilates and precursors

All metabolites were quantified using HPLC–electrospray ionization (ESI)–time-of-flight (TOF) MS. An aliquot of the culture medium was cleared by centrifugation (21,000 × g, 5 min, 4°C), mixed with an equal volume of cold methanol–water (1:1, v/v), and filtered using Amicon Ultra centrifugal filters (3,000 Da MW cutoff regenerated cellulose membrane; Millipore, Billerica, MA) prior to analysis. For the quantification of intracellular Avn, a cell pellet from 5 ml of culture was washed three times with water, suspended in cold methanol–water (1:1, v/v), sonicated twice for 30 s and centrifuged (21,000 × g, 5 min, 4°C). The supernatant was collected and filtered before analysis. The separation of metabolites was conducted on the Eclipse Plus Phenyl-hexyl column (250-mm length, 4.6-mm inside diameter, and 5-μm particle size; Agilent Technologies, Santa Clara, CA, USA) using an Agilent Technologies 1200 Series HPLC system. A sample injection volume of 5 μL was used throughout. The sample tray and column compartment were set to 4 and 50°C, respectively. The mobile phase was composed of 10 mM ammonium acetate (Sigma-Aldrich, St. Louis, MO, USA) in water (solvent A) and 10 mM ammonium acetate in 90% acetonitrile and 10% water (solvent B). The mobile phases were made up from a stock solution of 100 mM ammonium acetate and 0.7% formic acid (Sigma-Aldrich, St. Louis, MO, USA) in water. A flow rate of 0.5 ml/min was used, unless stated otherwise. Metabolites were separated via gradient elution under the following mobile phase compositions: 30% B (0 min), 80% B (12 min), 30% B (12.1 min), 30% B (12.5 min), 30% B (15.4 min). The flow rate was increased from 0.5 mL/min at 12.1 min to 1 mL/min at 12.5 min, and held at 1 mL/min for the remaining 2.9 min of the HPLC run. The HPLC system was coupled to an Agilent Technologies 6210 series time-of-flight mass spectrometer (for LC-TOF MS) via a MassHunter workstation (Agilent Technologies, CA, USA). Drying and nebulizing gases were set to 11 L/min and 30 lb/in2, respectively, and a drying-gas temperature of 330°C was used throughout. ESI was conducted in the negative ion mode and a capillary voltage of -3,500 V was utilized. All other MS conditions were described previously [2]. Metabolites were quantified via seven-point calibration curves of authentic standard compounds for which the R 2 coefficients were ≥ 0.99.

Notes

Authors’ Affiliations

(1)
Joint BioEnergy Institute
(2)
Physical Biosciences Division, Lawrence Berkeley National Laboratory
(3)
California Institute for Quantitative Biosciences and the Synthetic Biology Institute at UC Berkeley
(4)
Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food
(5)
Department of Bioengineering, Department of Chemical & Biomolecular Engineering, University of California

References

  1. Eudes A, Juminaga D, Baidoo E, Collins FW, Keasling JD, Loqué D: Production of hydroxycinnamoyl anthranilates from glucose in Escherichia coli. Microb Cell Fact. 2013, 12: 62-10.1186/1475-2859-12-62.View ArticleGoogle Scholar
  2. Eudes A, Baidoo EE, Yang F, Burd H, Hadi MZ, Collins FW, Keasling JD, Loqué D: Production of tranilast [N-(3′,4′-dimethoxycinnamoyl)-anthranilic acid] and its analogs in yeast Saccharomyces cerevisiae. Appl Microbiol Biotechnol. 2011, 89: 989-1000. 10.1007/s00253-010-2939-y.View ArticleGoogle Scholar

Copyright

© Eudes et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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