This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kwak, Y. H. Articles by Kim, H. B. Search for Related Content PubMed PubMed Citation Articles by Kwak, Y. H. Articles by Kim, H. B. Agricola Articles by Kwak, Y. H. Articles by Kim, H. B.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2003, p. 4390-4395, Vol. 69, No. 8
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.8.4390-4395.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

Young Hak Kwak,¹ Dong Seok Lee,² and Han Bok Kim^1*

Department of Life Science, Hoseo University, Asan-Si, ChungNam 336-795,¹ Department of Medical Laboratory Science, Inje University, Kimhae 621-749, Korea²

Received 1 October 2002/ Accepted 14 May 2003

The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5 and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5 NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5 NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared for their overproduction and easy purification. GST-EcNfsA, GST-EcNFsB, and GST-VhNFsA efficiently reduced nitrofurazone and 2,4,6-trinitrotoluene (TNT) as their nitro substrates. The K_m values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 11.8, 23.5, and 5.4 µM, respectively. The V_max values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA were 3.8, 3.9, and 10.7 nmol/min/mg of protein, respectively. GST-VhNfsA was the most effective of the three chromate reductases, as determined by each V_max/K_m value. The optimal temperatures of GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 55, 30, and 30°C, respectively. Thus, it is confirmed that nitroreductase can also act as a chromate reductase. Nitroreductases may be used in chromate remediation. GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA have a molecular mass of 50 kDa and exist as a monomer in solution. Thin-layer chromatography showed that GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA contain FMN as a cofactor. GST-VhNfsA reduced Cr(VI) to Cr(III). Cr(III) was much less toxic to E. coli than Cr(VI).

---

* Corresponding author. Mailing address: Department of Life Science, Hoseo University, Asan-Si, ChungNam 336-795, Korea. Phone: (82) 41-540-5624. Fax: (82) 41-548-6231. E-mail: hbkim{at}office.hoseo.ac.kr.

---

Applied and Environmental Microbiology, August 2003, p. 4390-4395, Vol. 69, No. 8
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.8.4390-4395.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Opperman, D. J., Piater, L. A., van Heerden, E. (2008). A Novel Chromate Reductase from Thermus scotoductus SA-01 Related to Old Yellow Enzyme. J. Bacteriol. 190: 3076-3082 [Abstract] [Full Text]  
• Brown, S. D., Thompson, M. R., VerBerkmoes, N. C., Chourey, K., Shah, M., Zhou, J., Hettich, R. L., Thompson, D. K. (2006). Molecular Dynamics of the Shewanella oneidensis Response to Chromate Stress. Mol. Cell. Proteomics 5: 1054-1071 [Abstract] [Full Text]