HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jung, Y.-S. Articles by Burgess, B. K. Search for Related Content PubMed PubMed Citation Articles by Jung, Y.-S. Articles by Burgess, B. K. Social Bookmarking                      What's this?

J Biol Chem, Vol. 274, Issue 5, 2978-2987, January 29, 1999

Complex Formation between Azotobacter vinelandii Ferredoxin I and Its Physiological Electron Donor NADPH-Ferredoxin Reductase

Yean-Sung Jung, Victoria A. Roberts^§, C. David Stout^§, and Barbara K. Burgess

From the  Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697 and the ^§ Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037

In Azotobacter vinelandii, deletion of the fdxA gene, which encodes ferredoxin I (FdI), leads to activation of the expression of the fpr gene, which encodes NADPH-ferredoxin reductase (FPR). In order to investigate the relationship of these two proteins further, the interactions of the two purified proteins have been examined. AvFdI forms a specific 1:1 cross-linked complex with AvFPR through ionic interactions formed between the Lys residues of FPR and Asp/Glu residues of FdI. The Lys in FPR has been identified as Lys²⁵⁸, a residue that forms a salt bridge with one of the phosphate oxygens of FAD in the absence of FdI. UV-Vis and circular dichroism data show that on binding FdI, the spectrum of the FPR flavin is hyperchromatic and red-shifted, confirming the interaction region close to the FAD. Cytochrome c reductase assays and electron paramagnetic resonance data show that electron transfer between the two proteins is pH-dependent and that the [3Fe-4S]⁺ cluster of FdI is specifically reduced by NADPH via FPR, suggesting that the [3Fe-4S] cluster is near FAD in the complex. To further investigate the FPR:FdI interaction, the electrostatic potentials for each protein were calculated. Strongly negative regions around the [3Fe-4S] cluster of FdI are electrostatically complementary with a strongly positive region overlaying the FAD of FPR, centered on Lys²⁵⁸. These proposed interactions of FdI with FPR are consistent with cross-linking, peptide mapping, spectroscopic, and electron transfer data and strongly support the suggestion that the two proteins are physiological redox partners.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				J. Yeom, C. O. Jeon, E. L. Madsen, and W. Park In Vitro and In Vivo Interactions of Ferredoxin-NADP+ Reductases in Pseudomonas putida J. Biochem., April 1, 2009; 145(4): 481 - 491. [Abstract] [Full Text] [PDF]

				S. S. Mansy, G. Wu, K. K. Surerus, and J. A. Cowan Iron-Sulfur Cluster Biosynthesis. THERMATOGA MARITIMA IscU IS A STRUCTURED IRON-SULFUR CLUSTER ASSEMBLY PROTEIN J. Biol. Chem., June 7, 2002; 277(24): 21397 - 21404. [Abstract] [Full Text] [PDF]

				K.-S. Yoon, C. Bobst, C. F. Hemann, R. Hille, and F. R. Tabita Spectroscopic and Functional Properties of Novel 2[4Fe-4S] Cluster-containing Ferredoxins from the Green Sulfur Bacterium Chlorobium tepidum J. Biol. Chem., November 16, 2001; 276(47): 44027 - 44036. [Abstract] [Full Text] [PDF]

				Y.-S. Jung, H. S. Gao-Sheridan, J. Christiansen, D. R. Dean, and B. K. Burgess Purification and Biophysical Characterization of a New [2Fe-2S] Ferredoxin from Azotobacter vinelandii, a Putative [Fe-S] Cluster Assembly/Repair Protein J. Biol. Chem., November 5, 1999; 274(45): 32402 - 32410. [Abstract] [Full Text] [PDF]

				K. Regnstrom, S. Sauge-Merle, K. Chen, and B. K. Burgess In Azotobacter vinelandii, the E1 subunit of the pyruvate dehydrogenase complex binds fpr promoter region DNA and ferredoxin I PNAS, October 26, 1999; 96(22): 12389 - 12393. [Abstract] [Full Text] [PDF]

				Y.-S. Jung, C. A. Bonagura, G. J. Tilley, H. S. Gao-Sheridan, F. A. Armstrong, C. D. Stout, and B. K. Burgess Structure of C42D Azotobacter vinelandii FdI. A Cys-X-X-Asp-X-X-Cys MOTIF LIGATES AN AIR-STABLE [4Fe-4S]2+/+ CLUSTER J. Biol. Chem., November 17, 2000; 275(47): 36974 - 36983. [Abstract] [Full Text] [PDF]