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

J. Biol. Chem., Vol. 281, Issue 19, 13652-13662, May 12, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/19/13652    most recent M600824200v1 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 Lansky, I. B. Articles by Wilks, A. Search for Related Content PubMed PubMed Citation Articles by Lansky, I. B. Articles by Wilks, A. Social Bookmarking                      What's this?

The Cytoplasmic Heme-binding Protein (PhuS) from the Heme Uptake System of Pseudomonas aeruginosa Is an Intracellular Heme-trafficking Protein to the -Regioselective Heme Oxygenase^*

Ila B. Lansky, Gudrun S. Lukat-Rodgers, Darci Block, Kenton R. Rodgers, Melanie Ratliff¹, and Angela Wilks²

From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201 and the Department of Chemistry, Biochemistry and Molecular Biology, North Dakota State University, Fargo, North Dakota 58105-5516

The uptake and utilization of heme as an iron source is a receptor-mediated process in bacterial pathogens and involves a number of proteins required for internalization and degradation of heme. In the following report we provide the first in-depth spectroscopic and functional characterization of a cytoplasmic heme-binding protein PhuS from the opportunistic pathogen Pseudomonas aeruginosa. Spectroscopic characterization of the heme-PhuS complex at neutral pH indicates that the heme is predominantly six-coordinate low spin. However, the resonance Raman spectra and global fit analysis of the UV-visible spectra show that at all pH values between 6 and 10 three distinct species are present to varying degrees. The distribution of the heme across multiple spin states and coordination number highlights the flexibility of the heme environment. We provide further evidence that the cytoplasmic heme-binding proteins, contrary to previous reports, are not heme oxygenases. The degradation of the heme-PhuS complex in the presence of a reducing agent is a result of H₂O₂ formed by direct reduction of molecular oxygen and does not yield biliverdin. In contrast, the heme-PhuS complex is an intracellular heme trafficking protein that specifically transfers heme to the previously characterized iron-regulated heme oxygenase pa-HO. Surface plasmon resonance experiments confirm that the transfer of heme is driven by a specific protein-protein interaction. This data taken together with the spectroscopic characterization is consistent with a protein that functions to shuttle heme within the cell.

Received for publication, January 26, 2006 , and in revised form, March 3, 2006.

^* This work was supported by National Institutes of Health Grant AI-48551 (to A. W.) and by National Center for Research Resources Grant P20 RR15556 and United States Department of Agriculture Grant ND05299 (to K. R. R.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ Current address: Dept. of Microbiology and Immunology, Emory School of Medicine, Atlanta, GA 30322.

² To whom correspondence should be addressed: 20 Penn St., University of Maryland, Baltimore, MD 21201. Tel.: 410-706-2537; Fax: 410-706-5017; E-mail: awilks{at}rx.umaryland.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				A. P. Kaur, I. B. Lansky, and A. Wilks The Role of the Cytoplasmic Heme-binding Protein (PhuS) of Pseudomonas aeruginosa in Intracellular Heme Trafficking and Iron Homeostasis J. Biol. Chem., January 2, 2009; 284(1): 56 - 66. [Abstract] [Full Text] [PDF]

				K. A. Burkhard and A. Wilks Characterization of the Outer Membrane Receptor ShuA from the Heme Uptake System of Shigella dysenteriae: SUBSTRATE SPECIFICITY AND IDENTIFICATION OF THE HEME PROTEIN LIGANDS J. Biol. Chem., May 18, 2007; 282(20): 15126 - 15136. [Abstract] [Full Text] [PDF]

				M. D. L. Suits, N. Jaffer, and Z. Jia Structure of the Escherichia coli O157:H7 Heme Oxygenase ChuS in Complex with Heme and Enzymatic Inactivation by Mutation of the Heme Coordinating Residue His-193 J. Biol. Chem., December 1, 2006; 281(48): 36776 - 36782. [Abstract] [Full Text] [PDF]

				S. Schneider, K. H. Sharp, P. D. Barker, and M. Paoli An Induced Fit Conformational Change Underlies the Binding Mechanism of the Heme Transport Proteobacteria-Protein HemS J. Biol. Chem., October 27, 2006; 281(43): 32606 - 32610. [Abstract] [Full Text] [PDF]

				N. Izadi-Pruneyre, F. Huche, G. S. Lukat-Rodgers, A. Lecroisey, R. Gilli, K. R. Rodgers, C. Wandersman, and P. Delepelaire The Heme Transfer from the Soluble HasA Hemophore to Its Membrane-bound Receptor HasR Is Driven by Protein-Protein Interaction from a High to a Lower Affinity Binding Site J. Biol. Chem., September 1, 2006; 281(35): 25541 - 25550. [Abstract] [Full Text] [PDF]