, Volume 23, Issue 6, pp 1129–1138 | Cite as

Proteogenomic and functional analysis of chromate reduction in Acidiphilium cryptum JF-5, an Fe(III)-respiring acidophile

  • Timothy S. MagnusonEmail author
  • Michael W. Swenson
  • Andrzej J. Paszczynski
  • Lee A. Deobald
  • David Kerk
  • David E. Cummings


Acidiphilium cryptum JF-5, an acidophilic iron-respiring Alphaproteobacterium, has the ability to reduce chromate under aerobic and anaerobic conditions, making it an intriguing and useful model organism for the study of extremophilic bacteria in bioremediation applications. Genome sequence annotation suggested two potential mechanisms of Cr(VI) reduction, namely, a number of c-type cytochromes, and a predicted NADPH-dependent Cr(VI) reductase. In laboratory studies using pure cultures of JF-5, an NADPH-dependent chromate reductase activity was detected primarily in soluble protein fractions, and a periplasmic c-type cytochrome (ApcA) was also present, representing two potential means of Cr(VI) reduction. Upon further examination, it was determined that the NADPH-dependent activity was not specific for Cr(VI), and the predicted proteins were not detected in Cr(VI)-grown cultures. Proteomic data did show measureable amounts of ApcA in cells grown with Cr(VI). Purified ApcA is reducible by menadiol, and in turn can reduce Cr(VI), suggesting a means to obtain electrons from the respiratory chain and divert them to Cr(VI). Electrochemical measurements confirm that Cr reduction by ApcA is pH dependent, with low pH being favored. Homology modeling of ApcA and comparison to a known Cr(VI)-reducing c-type cytochrome structure revealed basic amino acids which could interact with chromate ion. From these studies, it can be concluded that A. cryptum has the physiologic and genomic capability to reduce Cr(VI) to the less toxic Cr(III). However, the expected chromate reductase mechanism may not be the primary means of Cr(VI) reduction in this organism.


Acidophile Chromium reduction Cytochrome c Proteomics 



The authors are grateful for support from the U.S. Department of Energy Environmental Remediation Science Program through Grant Number DE-FG-063626 (To TSM and DEC), and National Science Foundation Grant Number 0434023 (To TSM). We thank undergraduates Julienne Pharis and Andrew Fielding for laboratory assistance.


  1. Assfalg M, Bertini I, Bruschi M, Michel C, Turano P (2002) The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7). Proc Natl Acad Sci USA 99:9750–9754CrossRefPubMedGoogle Scholar
  2. Bansal R, Deobald LA, Crawford RL, Paszczynski AJ (2009) Proteomic detection of proteins involved in perchlorate and chlorate metabolism. Biodegradation 20:603–620CrossRefPubMedGoogle Scholar
  3. Barton LL, Goulhen F, Bruschi M, Woodards NA, Plunkett RM, Rietmeijer FJM (2007) The bacterial metallome: composition and stability with specific reference to the anaerobic bacterium Desulfovibrio desulfuricans. Biometals 20:291–302CrossRefPubMedGoogle Scholar
  4. Bordoli L, Kiefer F, Arnold K, Benkert P, Battey J, Schwede T (2009) Protein structure homology modeling using SWISS-MODEL workspace. Nat Protoc 4:1–13CrossRefPubMedGoogle Scholar
  5. Cervantes C, Campos-Garcia J, Devars S, Gutierrez-Corona F, Loza-Tavera H, Torres-Guzman JC, Moreno-Sanchez R (2001) Interactions of chromium with microorganisms and plants. FEMS Microbiol Rev 25:335–347CrossRefPubMedGoogle Scholar
  6. Chakraborty AR, Mishra RK (1992) Speciation and Determination of Chromium in Waters. Chem Speciation Bioavail 4:131–134Google Scholar
  7. Chardin B, Giudici-Orticoni MT, De Luca G, Guigliarelli B, Bruschi M (2003) Hydrogenases in sulfate-reducing bacteria function as chromium reductase. Appl Microbiol Biotechnol 63:315–321CrossRefPubMedGoogle Scholar
  8. Cummings DE, Fendorf S, Singh N, Sani RK, Peyton BM, Magnuson TS (2007) Reduction of Cr(VI) under acidic conditions by the facultative Fe(III)-reducing bacterium Acidiphilium cryptum. Environ Sci Technol 41:146–152CrossRefPubMedGoogle Scholar
  9. Desai C, Jain K, Madamwar D (2008a) Evaluation of In vitro Cr(VI) reduction potential in cytosolic extracts of three indigenous Bacillus sp isolated from Cr(VI) polluted industrial landfill. Bioresour Technol 99:6059–6069CrossRefPubMedGoogle Scholar
  10. Desai C, Jain K, Madamwar D (2008b) Hexavalent chromate reductase activity in cytosolic fractions of Pseudomonas sp G1DM21 isolated from Cr(VI) contaminated industrial landfill. Process Biochem 43:713–721CrossRefGoogle Scholar
  11. Francis CA, Obraztsova AY, Tebo BM (2000) Dissimilatory metal reduction by the facultative anaerobe Pantoea agglomerans SP1. Appl Environ Microbiol 66:543–548CrossRefPubMedGoogle Scholar
  12. Francisco R, Alpoim MC, Morais PV (2002) Diversity of chromium-resistant and -reducing bacteria in a chromium-contaminated activated sludge. J Appl Microbiol 92:837–843CrossRefPubMedGoogle Scholar
  13. Ginder-Vogel M, Borch T, Mayes MA, Jardine PM, Fendorf S (2005) Chromate reduction and retention processes within arid subsurface environments. Environ Sci Technol 39:7833–7839CrossRefPubMedGoogle Scholar
  14. Gonzalez CF, Ackerley DF, Lynch SV, Matin A (2005) ChrR, a soluble quinone reductase of Pseudomonas putida that defends against H2O2. J Biol Chem 280:22590–22595CrossRefPubMedGoogle Scholar
  15. He YT, Bigham JM, Traina SJ (2005) Biotite dissolution and Cr(VI) reduction at elevated pH and ionic strength. Geochim Cosmochim Acta 69:3791–3800CrossRefGoogle Scholar
  16. Horton RN, Apel WA, Thompson VS, Sheridan PP (2006) Low temperature reduction of hexavalent chromium by a microbial enrichment consortium and a novel strain of Arthrobacter aurescens. BMC Microbiology 6:5–12CrossRefPubMedGoogle Scholar
  17. Humphrey W, Dalke A, Schulten K (1996) VMD-Visual Molecular Dynamics. J Molec Graphics 14:33–38CrossRefGoogle Scholar
  18. Kelley LA, Sternberg MJ (2009) Protein structure prediction on the Web: a case study using the Phyre server. Nat Protoc 4:363–371CrossRefPubMedGoogle Scholar
  19. Kieft TL, Fredrickson JK, Onstott TC, Gorby YA, Kostandarithes HM, Bailey TJ, Kennedy DW, Li SW, Plymale AE, Spadoni CM, Gray MS (1999) Dissimilatory reduction of Fe(III) and other electron acceptors by a Thermus isolate. Appl Environ Microbiol 65:1214–1221PubMedGoogle Scholar
  20. Mazoch J, Tesarik R, Sedlacek V, Kucera I, Turanek J (2004) Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans. Eur J Biochem 271:553–562CrossRefPubMedGoogle Scholar
  21. Opperman DJ, van Heerden E (2008) A membrane-associated protein with Cr(VI)-reducing activity from Thermus scotoductus SA-01. FEMS Microbiol Lett 280:210–218CrossRefPubMedGoogle Scholar
  22. Opperman DJ, Piater LA, van Heerden E (2008) A novel chromate reductase from Thermus scotoductus SA-01 related to old yellow enzyme. J Bacteriol 190:3076–3082CrossRefPubMedGoogle Scholar
  23. Park CH, Keyhan M, Wielinga B, Fendorf S, Matin A (2000) Purification to homogeneity and characterization of a novel Pseudomonas putida chromate reductase. Appl Environ Microbiol 66:1788–1795CrossRefPubMedGoogle Scholar
  24. Schagger H, von Jagow G (1987) Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the separation of proteins in the range from 1 to 100 kDa. Anal Biochem 166:368–379CrossRefPubMedGoogle Scholar
  25. Sedlacek V, van Spanning RJM, Kucera I (2009) Characterization of the quinone reductase activity of the ferric reductase B protein from Paracoccus denitrificans. Arch Biochem Biophys 483:29–36CrossRefPubMedGoogle Scholar
  26. Tebo BM, Obraztsova AY (1998) Sulfate-reducing bacterium grows with Cr(VI), U(VI), Mn(IV), and Fe(III) as electron acceptors. FEMS Microbiol Lett 162:193–198CrossRefGoogle Scholar
  27. Viti C, Pace A, Giovannetti L (2003) Characterization of Cr(VI)-resistant bacteria isolated from chromium-contaminated soil by tannery activity. Curr Microbiol 46:1–5CrossRefPubMedGoogle Scholar
  28. Wolin EA, Wolin MJ, Wolfe RS (1963) Formation Of Methane By Bacterial Extracts. J Biol Chem 238:2882PubMedGoogle Scholar
  29. Zayed AM, Terry N (2003) Chromium in the environment: factors affecting biological remediation. Plant Soil 249:139–156CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  • Timothy S. Magnuson
    • 1
    Email author
  • Michael W. Swenson
    • 1
  • Andrzej J. Paszczynski
    • 2
  • Lee A. Deobald
    • 2
  • David Kerk
    • 3
  • David E. Cummings
    • 3
  1. 1.Department of Biological SciencesIdaho State UniversityPocatelloUSA
  2. 2.Environmental Biotechnology InstituteUniversity of IdahoMoscowUSA
  3. 3.Department of BiologyPoint Loma Nazarene UniversitySan DiegoUSA

Personalised recommendations