1
|
Keith AD, Sawyer EB, Choy DCY, Xie Y, Biggs GS, Klein OJ, Brear PD, Wales DJ, Barker PD. Combining experiment and energy landscapes to explore anaerobic heme breakdown in multifunctional hemoproteins. Phys Chem Chem Phys 2024; 26:695-712. [PMID: 38053511 DOI: 10.1039/d3cp03897a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
To survive, many pathogens extract heme from their host organism and break down the porphyrin scaffold to sequester the Fe2+ ion via a heme oxygenase. Recent studies have revealed that certain pathogens can anaerobically degrade heme. Our own research has shown that one such pathway proceeds via NADH-dependent heme degradation, which has been identified in a family of hemoproteins from a range of bacteria. HemS, from Yersinia enterocolitica, is the main focus of this work, along with HmuS (Yersinia pestis), ChuS (Escherichia coli) and ShuS (Shigella dysenteriae). We combine experiments, Energy Landscape Theory, and a bioinformatic investigation to place these homologues within a wider phylogenetic context. A subset of these hemoproteins are known to bind certain DNA promoter regions, suggesting not only that they can catalytically degrade heme, but that they are also involved in transcriptional modulation responding to heme flux. Many of the bacterial species responsible for these hemoproteins (including those that produce HemS, ChuS and ShuS) are known to specifically target oxygen-depleted regions of the gastrointestinal tract. A deeper understanding of anaerobic heme breakdown processes exploited by these pathogens could therefore prove useful in the development of future strategies for disease prevention.
Collapse
Affiliation(s)
- Alasdair D Keith
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Elizabeth B Sawyer
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Desmond C Y Choy
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Yuhang Xie
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - George S Biggs
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Oskar James Klein
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Paul D Brear
- Department of Biochemistry, University of Cambridge, Sanger Building, Cambridge CB2 1GA, UK
| | - David J Wales
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| | - Paul D Barker
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
| |
Collapse
|
2
|
Rivera M. Mobilization of iron stored in bacterioferritin, a new target for perturbing iron homeostasis and developing antibacterial and antibiofilm molecules. J Inorg Biochem 2023; 247:112306. [PMID: 37451083 DOI: 10.1016/j.jinorgbio.2023.112306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/08/2023] [Accepted: 06/24/2023] [Indexed: 07/18/2023]
Abstract
Antibiotic resistance is a global public health threat. The care of chronic infections is complicated by bacterial biofilms. Biofilm embedded cells can be up to 1000-fold more tolerant to antibiotic treatment than planktonic cells. Antibiotic tolerance is a condition which does not involve mutation and enables bacteria to survive in the presence of antibiotics. The antibiotic tolerance of biofilm-cells often renders antibiotics ineffective, even against strains that do not carry resistance-impairing mutations. This review discusses bacterial iron homeostasis and the strategies being developed to target this bacterial vulnerability, with emphasis on a recently proposed approach which aims at targeting the iron storage protein bacterioferritin (Bfr) and its physiological partner, the ferredoxin Bfd. Bfr regulates cytosolic iron concentrations by oxidizing Fe2+ and storing Fe3+ in its internal cavity, and by forming a complex with Bfd to reduce Fe3+ in the internal cavity and release Fe2+ to the cytosol. Blocking the Bfr-Bfd complex in P. aeruginosa cells causes an irreversible accumulation of Fe3+ in BfrB and simultaneous cytosolic iron depletion, which leads to impaired biofilm maintenance and biofilm cell death. Recently discovered small molecule inhibitors of the Bfr-Bfd complex, which bind Bfr at the Bfd binding site, inhibit iron mobilization, and elicit biofilm cell death.
Collapse
Affiliation(s)
- Mario Rivera
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, USA.
| |
Collapse
|
3
|
Fu J, Nisbett LM, Guo Y, Boon EM. NosP Detection of Heme Modulates Burkholderia thailandensis Biofilm Formation. Biochemistry 2023; 62:2426-2441. [PMID: 37498555 PMCID: PMC10478957 DOI: 10.1021/acs.biochem.3c00187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Aggregated bacteria embedded within self-secreted extracellular polymeric substances, or biofilms, are resistant to antibiotics and cause chronic infections. As such, they are a significant public health threat. Heme is an abundant iron source for pathogenic bacteria during infection; many bacteria have systems to detect heme assimilated from host cells, which is correlated with the transition between acute and chronic infection states. Here, we investigate the heme-sensing function of a newly discovered multifactorial sensory hemoprotein called NosP and its role in biofilm regulation in the soil-dwelling bacterium Burkholderia thailandensis, the close surrogate of Bio-Safety-Level-3 pathogen Burkholderia pseudomallei. The NosP family protein has previously been shown to exhibit both nitric oxide (NO)- and heme-sensing functions and to regulate biofilms through NosP-associated histidine kinases and two-component systems. Our in vitro studies suggest that BtNosP exhibits heme-binding kinetics and thermodynamics consistent with a labile heme-responsive protein and that the holo-form of BtNosP acts as an inhibitor of its associated histidine kinase BtNahK. Furthermore, our in vivo studies suggest that increasing the concentration of extracellular heme decreases B. thailandensis biofilm formation, and deletion of nosP and nahK abolishes this phenotype, consistent with a model that BtNosP detects heme and exerts an inhibitory effect on BtNahK to decrease the biofilm.
Collapse
Affiliation(s)
- Jiayuan Fu
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Lisa-Marie Nisbett
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Yulong Guo
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Elizabeth M Boon
- Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York 11794-3400, United States
| |
Collapse
|
4
|
High-Level Expression of Cell-Surface Signaling System Hxu Enhances Pseudomonas aeruginosa Bloodstream Infection. Infect Immun 2022; 90:e0032922. [PMID: 36169312 PMCID: PMC9584290 DOI: 10.1128/iai.00329-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bloodstream infections (BSIs) caused by Pseudomonas aeruginosa are associated with a high mortality rate in the clinic. However, the fitness mechanisms responsible for the evolution of virulence factors that facilitate the dissemination of P. aeruginosa to the bloodstream are poorly understood. In this study, a transcriptomic analysis of the BSI-associated P. aeruginosa clinical isolates showed a high-level expression of cell-surface signaling (CSS) system Hxu. Whole-genome sequencing and comparative genomics of these isolates showed that a mutation in rnfE gene was responsible for the elevated expression of the Hxu-CSS pathway. Most importantly, deletion of the hxuIRA gene cluster in a laboratory strain PAO1 reduced its BSI capability while overexpression of the HxuIRA pathway promoted BSI in a murine sepsis model. We further demonstrated that multiple components in the blood plasma, including heme, hemoglobin, the heme-scavenging proteins haptoglobin, and hemopexin, as well as the iron-delivery protein transferrin, could activate the Hxu system. Together, these studies suggested that the Hxu-CSS system was an important signal transduction pathway contributing to the adaptive pathogenesis of P. aeruginosa in BSI.
Collapse
|
5
|
Huo H, Zong L, Liu Y, Chen W, Chen J, Wei G. Rhizobial HmuS pSym as a heme-binding factor is required for optimal symbiosis between Mesorhizobium amorphae CCNWGS0123 and Robinia pseudoacacia. PLANT, CELL & ENVIRONMENT 2022; 45:2191-2210. [PMID: 35419804 DOI: 10.1111/pce.14335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 01/15/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Nitrogen-fixing root nodules are formed by symbiotic association of legume hosts with rhizobia in nitrogen-deprived soils. Successful symbiosis is regulated by signals from both legume hosts and their rhizobial partners. HmuS is a heme degrading factor widely distributed in bacteria, but little is known about the role of rhizobial hmuS in symbiosis with legumes. Here, we found that inactivation of hmuSpSym in the symbiotic plasmid of Mesorhizobium amorphae CCNWGS0123 disrupted rhizobial infection, primordium formation, and nitrogen fixation in symbiosis with Robinia pseudoacacia. Although there was no difference in bacteroids differentiation, infected plant cells were shrunken and bacteroids were disintegrated in nodules of plants infected by the ΔhmuSpSym mutant strain. The balance of defence reaction was also impaired in ΔhmuSpSym strain-infected root nodules. hmuSpSym was strongly expressed in the nitrogen-fixation zone of mature nodules. Furthermore, the HmuSpSym protein could bind to heme but not degrade it. Inactivation of hmuSpSym led to significantly decreased expression levels of oxygen-sensing related genes in nodules. In summary, hmuSpSym of M. amorphae CCNWGS0123 plays an essential role in nodule development and maintenance of bacteroid survival within R. pseudoacacia cells, possibly through heme-binding in symbiosis.
Collapse
Affiliation(s)
- Haibo Huo
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Le Zong
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Yao Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Wenfeng Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences and Rhizobium Research Center, Ministry of Agriculture Key Laboratory of Soil Microbiology, China Agricultural University, Beijing, China
| | - Juan Chen
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, China
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| |
Collapse
|
6
|
Iron Homeostasis in Pseudomonas aeruginosa: Targeting Iron Acquisition and Storage as an Antimicrobial Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:29-68. [DOI: 10.1007/978-3-031-08491-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
7
|
Robinson EA, Frankenberg-Dinkel N, Xue F, Wilks A. Recombinant Production of Biliverdin IXβ and δ Isomers in the T7 Promoter Compatible Escherichia coli Nissle. Front Microbiol 2021; 12:787609. [PMID: 34956154 PMCID: PMC8692735 DOI: 10.3389/fmicb.2021.787609] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
The ability to obtain purified biliverdin IX (BVIX) isomers other than the commercially available BVIXα is limited due to the low yields obtained by the chemical coupled oxidation of heme. Chemical oxidation requires toxic chemicals, has very poor BVIX yields (<0.05%), and is not conducive to scalable production. Alternative approaches utilizing recombinant E. coli BL21 expressing a cyanobacterial heme oxygenase have been employed for the production BVIXα, but yields are limited by the rate of endogenous heme biosynthesis. Furthermore, the emerging roles of BVIXβ and BVIXδ in biology and their lack of commercial availability has led to a need for an efficient and scalable method with the flexibility to produce all three physiologically relevant BVIX isomers. Herein, we have taken advantage of an optimized non-pathogenic E. coli Nissle (EcN(T7)) strain that encodes an endogenous heme transporter and an integrated T7 polymerase gene. Protein production of the Pseudomonas aeruginosa BVIXβ and BVIXδ selective heme oxygenase (HemO) or its BVIXα producing mutant (HemOα) in the EcN(T7) strain provides a scalable method to obtain all three isomers, that is not limited by the rate of endogenous heme biosynthesis, due to the natural ability of EcN(T7) to transport extracellular heme. Additionally, we have optimized our previous LC-MS/MS protocol for semi-preparative separation and validation of the BVIX isomers. Utilizing this new methodology for scalable production and separation we have increased the yields of the BVIXβ and -δ isomers >300-fold when compared to the chemical oxidation of heme.
Collapse
Affiliation(s)
- Elizabeth A. Robinson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States
| | - Nicole Frankenberg-Dinkel
- Fachbereich Biologie, Abt. Mikrobiologie, Technische Universität Kaiserlautern, Kaiserslautern, Germany
| | - Fengtian Xue
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States
| | - Angela Wilks
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, United States
| |
Collapse
|
8
|
Kihn KC, Wilson T, Smith AK, Bradshaw RT, Wintrode PL, Forrest LR, Wilks A, Deredge DJ. Modeling the native ensemble of PhuS using enhanced sampling MD and HDX-ensemble reweighting. Biophys J 2021; 120:5141-5157. [PMID: 34767787 PMCID: PMC8715216 DOI: 10.1016/j.bpj.2021.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/13/2021] [Accepted: 11/04/2021] [Indexed: 11/25/2022] Open
Abstract
The cytoplasmic heme binding protein from Pseudomonas aeruginosa, PhuS, plays two essential roles in regulating heme uptake and iron homeostasis. First, PhuS shuttles exogenous heme to heme oxygenase (HemO) for degradation and iron release. Second, PhuS binds DNA and modulates the transcription of the prrF/H small RNAs (sRNAs) involved in the iron-sparing response. Heme binding to PhuS regulates this dual function, as the unliganded form binds DNA, whereas the heme-bound form binds HemO. Crystallographic studies revealed nearly identical structures for apo- and holo-PhuS, and yet numerous solution-based measurements indicate that heme binding is accompanied by large conformational rearrangements. In particular, hydrogen-deuterium exchange mass spectrometry (HDX-MS) of apo- versus holo-PhuS revealed large differences in deuterium uptake, notably in α-helices 6, 7, and 8 (α6,7,8), which contribute to the heme binding pocket. These helices were mostly labile in apo-PhuS but largely protected in holo-PhuS. In contrast, in silico-predicted deuterium uptake levels of α6,7,8 from molecular dynamics (MD) simulations of the apo- and holo-PhuS structures are highly similar, consistent only with the holo-PhuS HDX-MS data. To rationalize this discrepancy between crystal structures, simulations, and observed HDX-MS, we exploit a recently developed computational approach (HDXer) that fits the relative weights of conformational populations within an ensemble of structures to conform to a target set of HDX-MS data. Here, a combination of enhanced sampling MD, HDXer, and dimensionality reduction analysis reveals an apo-PhuS conformational landscape in which α6, 7, and 8 are significantly rearranged compared to the crystal structure, including a loss of secondary structure in α6 and the displacement of α7 toward the HemO binding interface. Circular dichroism analysis confirms the loss of secondary structure, and the extracted ensembles of apo-PhuS and of heme-transfer-impaired H212R mutant, are consistent with known heme binding and transfer properties. The proposed conformational landscape provides structural insights into the modulation by heme of the dual function of PhuS.
Collapse
Affiliation(s)
- Kyle C Kihn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Tyree Wilson
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Ally K Smith
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | | | - Patrick L Wintrode
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland
| | - Daniel J Deredge
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland.
| |
Collapse
|
9
|
Extracellular haem utilization by the opportunistic pathogen Pseudomonas aeruginosa and its role in virulence and pathogenesis. Adv Microb Physiol 2021; 79:89-132. [PMID: 34836613 DOI: 10.1016/bs.ampbs.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Iron is an essential micronutrient for all bacteria but presents a significant challenge given its limited bioavailability. Furthermore, iron's toxicity combined with the need to maintain iron levels within a narrow physiological range requires integrated systems to sense, regulate and transport a variety of iron complexes. Most bacteria encode systems to chelate and transport ferric iron (Fe3+) via siderophore receptor mediated uptake or via cytoplasmic energy dependent transport systems. Pathogenic bacteria have further lowered the barrier to iron acquisition by employing systems to utilize haem as a source of iron. Haem, a lipophilic and toxic molecule, presents a significant challenge for transport into the cell. As such pathogenic bacteria have evolved sophisticated cell surface signaling (CSS) and transport systems to sense and obtain haem from the host. Once internalized haem is cleaved by both oxidative and non-oxidative mechanisms to release iron. Herein we summarize our current understanding of the mechanism of haem sensing, uptake and utilization in Pseudomonas aeruginosa, its role in pathogenesis and virulence, and the potential of these systems as antimicrobial targets.
Collapse
|
10
|
White AM, Zhang Y, Shamul JG, Xu J, Kwizera EA, Jiang B, He X. Deep Learning-Enabled Label-Free On-Chip Detection and Selective Extraction of Cell Aggregate-Laden Hydrogel Microcapsules. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100491. [PMID: 33899299 PMCID: PMC8203426 DOI: 10.1002/smll.202100491] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/27/2021] [Indexed: 05/05/2023]
Abstract
Microfluidic encapsulation of cells/tissues in hydrogel microcapsules has attracted tremendous attention in the burgeoning field of cell-based medicine. However, when encapsulating rare cells and tissues (e.g., pancreatic islets and ovarian follicles), the majority of the resultant hydrogel microcapsules are empty and should be excluded from the sample. Furthermore, the cell-laden hydrogel microcapsules are usually suspended in an oil phase after microfluidic generation, while the microencapsulated cells require an aqueous phase for further culture/transplantation and long-term suspension in oil may compromise the cells/tissues. Thus, real-time on-chip selective extraction of cell-laden hydrogel microcapsules from oil into aqueous phase is crucial to the further use of the microencapsulated cells/tissues. Contemporary extraction methods either require labeling of cells for their identification along with an expensive detection system or have a low extraction purity (<≈30%). Here, a deep learning-enabled approach for label-free detection and selective extraction of cell-laden microcapsules with high efficiency of detection (≈100%) and extraction (≈97%), high purity of extraction (≈90%), and high cell viability (>95%) is reported. The utilization of deep learning to dynamically analyze images in real time for label-free detection and on-chip selective extraction of cell-laden hydrogel microcapsules is unique and may be valuable to advance the emerging cell-based medicine.
Collapse
Affiliation(s)
- Alisa M White
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - Yuntian Zhang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - James G Shamul
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - Jiangsheng Xu
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - Elyahb A Kwizera
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - Bin Jiang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
| | - Xiaoming He
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 20742, USA
- Robert E. Fischell Institute for Biomedical Devices, University of Maryland, College Park, MD, 20742, USA
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland, Baltimore, MD, 21201, USA
| |
Collapse
|
11
|
Traore ES, Li J, Chiura T, Geng J, Sachla AJ, Yoshimoto F, Eichenbaum Z, Davis I, Mak PJ, Liu A. Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus. Molecules 2021; 26:549. [PMID: 33494451 PMCID: PMC7865249 DOI: 10.3390/molecules26030549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/23/2022] Open
Abstract
HupZ is an expected heme degrading enzyme in the heme acquisition and utilization pathway in Group A Streptococcus. The isolated HupZ protein containing a C-terminal V5-His6 tag exhibits a weak heme degradation activity. Here, we revisited and characterized the HupZ-V5-His6 protein via biochemical, mutagenesis, protein quaternary structure, UV-vis, EPR, and resonance Raman spectroscopies. The results show that the ferric heme-protein complex did not display an expected ferric EPR signal and that heme binding to HupZ triggered the formation of higher oligomeric states. We found that heme binding to HupZ was an O2-dependent process. The single histidine residue in the HupZ sequence, His111, did not bind to the ferric heme, nor was it involved with the weak heme-degradation activity. Our results do not favor the heme oxygenase assignment because of the slow binding of heme and the newly discovered association of the weak heme degradation activity with the His6-tag. Altogether, the data suggest that the protein binds heme by its His6-tag, resulting in a heme-induced higher-order oligomeric structure and heme stacking. This work emphasizes the importance of considering exogenous tags when interpreting experimental observations during the study of heme utilization proteins.
Collapse
Affiliation(s)
- Ephrahime S. Traore
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Jiasong Li
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Tapiwa Chiura
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Jiafeng Geng
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Ankita J. Sachla
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Francis Yoshimoto
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; (A.J.S.); (Z.E.)
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| | - Piotr J. Mak
- Department of Chemistry, Saint Louis University, St. Louis, MO 63103, USA;
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (E.S.T.); (J.L.); (F.Y.); (I.D.)
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA;
| |
Collapse
|
12
|
Wilson T, Mouriño S, Wilks A. The heme-binding protein PhuS transcriptionally regulates the Pseudomonas aeruginosa tandem sRNA prrF1,F2 locus. J Biol Chem 2021; 296:100275. [PMID: 33428928 PMCID: PMC7948967 DOI: 10.1016/j.jbc.2021.100275] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen requiring iron for its survival and virulence. P. aeruginosa can acquire iron from heme via the nonredundant heme assimilation system and Pseudomonas heme uptake (Phu) systems. Heme transported by either the heme assimilation system or Phu system is sequestered by the cytoplasmic protein PhuS. Furthermore, PhuS has been shown to specifically transfer heme to the iron-regulated heme oxygenase HemO. As the PhuS homolog ShuS from Shigella dysenteriae was observed to bind DNA as a function of its heme status, we sought to further determine if PhuS, in addition to its role in regulating heme flux through HemO, functions as a DNA-binding protein. Herein, through a combination of chromatin immunoprecipitation–PCR, EMSA, and fluorescence anisotropy, we show that apo-PhuS but not holo-PhuS binds upstream of the tandem iron-responsive sRNAs prrF1,F2. Previous studies have shown the PrrF sRNAs are required for sparing iron for essential proteins during iron starvation. Furthermore, under certain conditions, a heme-dependent read through of the prrF1 terminator yields the longer PrrH transcript. Quantitative PCR analysis of P. aeruginosa WT and ΔphuS strains shows that loss of PhuS abrogates the heme-dependent regulation of PrrF and PrrH levels. Taken together, our data show that PhuS, in addition to its role in extracellular heme metabolism, also functions as a transcriptional regulator by modulating PrrF and PrrH levels in response to heme. This dual function of PhuS is central to integrating extracellular heme utilization into the PrrF/PrrH sRNA regulatory network that is critical for P. aeruginosa adaptation and virulence within the host.
Collapse
Affiliation(s)
- Tyree Wilson
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Susana Mouriño
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA.
| |
Collapse
|
13
|
Quantitative proteomic reveals gallium maltolate induces an iron-limited stress response and reduced quorum-sensing in Pseudomonas aeruginosa. J Biol Inorg Chem 2020; 25:1153-1165. [DOI: 10.1007/s00775-020-01831-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/21/2020] [Indexed: 01/12/2023]
|
14
|
Ganley JG, D'Ambrosio HK, Shieh M, Derbyshire ER. Coculturing of Mosquito-Microbiome Bacteria Promotes Heme Degradation in Elizabethkingia anophelis. Chembiochem 2020; 21:1279-1284. [PMID: 31845464 DOI: 10.1002/cbic.201900675] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Indexed: 12/31/2022]
Abstract
Anopheles mosquito microbiomes are intriguing ecological niches. Within the gut, microbes adapt to oxidative stress due to heme and iron after blood meals. Although metagenomic sequencing has illuminated spatial and temporal fluxes of microbiome populations, limited data exist on microbial growth dynamics. Here, we analyze growth interactions between a dominant microbiome species, Elizabethkingia anophelis, and other Anopheles-associated bacteria. We find E. anophelis inhibits a Pseudomonas sp. via an antimicrobial-independent mechanism and observe biliverdins, heme degradation products, upregulated in cocultures. Purification and characterization of E. anophelis HemS demonstrates heme degradation, and we observe hemS expression is upregulated when cocultured with Pseudomonas sp. This study reveals a competitive microbial interaction between mosquito-associated bacteria and characterizes the stimulation of heme degradation in E. anophelis when grown with Pseudomonas sp.
Collapse
Affiliation(s)
- Jack G Ganley
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Hannah K D'Ambrosio
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Meg Shieh
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Emily R Derbyshire
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC, 27708, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, 213 Research Drive, Durham, NC, 27710, USA
| |
Collapse
|
15
|
Otero-Asman JR, García-García AI, Civantos C, Quesada JM, Llamas MA. Pseudomonas aeruginosa possesses three distinct systems for sensing and using the host molecule haem. Environ Microbiol 2019; 21:4629-4647. [PMID: 31390127 DOI: 10.1111/1462-2920.14773] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022]
Abstract
Pathogens have developed several strategies to obtain iron during infection, including the use of iron-containing molecules from the host. Haem accounts for the vast majority of the iron pool in vertebrates and thus represents an important source of iron for pathogens. Using a proteomic approach, we have identified in this work a previously uncharacterized system, which we name Hxu, that together with the known Has and Phu systems, is used by the human pathogen Pseudomonas aeruginosa to respond to haem. We show that the Has and Hxu systems are functional signal transduction pathways of the cell-surface signalling class and report the mechanism triggering the activation of these signalling systems. Both signalling cascades involve an outer membrane receptor (HasR and HxuA respectively) that upon sensing haem in the extracellular medium produces the activation of an σECF factor in the cytosol. HxuA has a major role in signalling and a minor role in haem acquisition in conditions in which the HasR and PhuR receptors or other sources of iron are present. Remarkably, P. aeruginosa compensates the lack of the HasR receptor by increasing the production of HxuA, which underscores the importance of haem signalling for this pathogen.
Collapse
Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Ana I García-García
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Cristina Civantos
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - José M Quesada
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| |
Collapse
|
16
|
Verstraete MM, Morales LD, Kobylarz MJ, Loutet SA, Laakso HA, Pinter TB, Stillman MJ, Heinrichs DE, Murphy MEP. The heme-sensitive regulator SbnI has a bifunctional role in staphyloferrin B production by Staphylococcus aureus. J Biol Chem 2019; 294:11622-11636. [PMID: 31197035 DOI: 10.1074/jbc.ra119.007757] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/12/2019] [Indexed: 01/30/2023] Open
Abstract
Staphylococcus aureus infection relies on iron acquisition from its host. S. aureus takes up iron through heme uptake by the iron-responsive surface determinant (Isd) system and by the production of iron-scavenging siderophores. Staphyloferrin B (SB) is a siderophore produced by the 9-gene sbn gene cluster for SB biosynthesis and efflux. Recently, the ninth gene product, SbnI, was determined to be a free l-serine kinase that produces O-phospho-l-serine (OPS), a substrate for SB biosynthesis. Previous studies have also characterized SbnI as a DNA-binding regulatory protein that senses heme to control sbn gene expression for SB synthesis. Here, we present crystal structures at 1.9-2.1 Å resolution of a SbnI homolog from Staphylococcus pseudintermedius (SpSbnI) in both apo form and in complex with ADP, a product of the kinase reaction; the latter confirmed the active-site location. The structures revealed that SpSbnI forms a dimer through C-terminal domain swapping and a dimer of dimers through intermolecular disulfide formation. Heme binding had only a modest effect on SbnI enzymatic activity, suggesting that its two functions are independent and structurally distinct. We identified a heme-binding site and observed catalytic heme transfer between a heme-degrading protein of the Isd system, IsdI, and SbnI. These findings support the notion that SbnI has a bifunctional role contributing precursor OPS to SB synthesis and directly sensing heme to control expression of the sbn locus. We propose that heme transfer from IsdI to SbnI enables S. aureus to control iron source preference according to the sources available in the environment.
Collapse
Affiliation(s)
- Meghan M Verstraete
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - L Daniela Morales
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Marek J Kobylarz
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Slade A Loutet
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Holly A Laakso
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Tyler B Pinter
- Department of Chemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Martin J Stillman
- Department of Chemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Michael E P Murphy
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
17
|
The effects of novel heme oxygenase inhibitors on the growth of Pseudomonas aeruginosa. Microb Pathog 2019; 129:64-67. [DOI: 10.1016/j.micpath.2019.01.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/19/2018] [Accepted: 01/30/2019] [Indexed: 11/24/2022]
|
18
|
Richard KL, Kelley BR, Johnson JG. Heme Uptake and Utilization by Gram-Negative Bacterial Pathogens. Front Cell Infect Microbiol 2019; 9:81. [PMID: 30984629 PMCID: PMC6449446 DOI: 10.3389/fcimb.2019.00081] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/08/2019] [Indexed: 02/06/2023] Open
Abstract
Iron is a transition metal utilized by nearly all forms of life for essential cellular processes, such as DNA synthesis and cellular respiration. During infection by bacterial pathogens, the host utilizes various strategies to sequester iron in a process termed, nutritional immunity. To circumvent these defenses, Gram-negative pathogens have evolved numerous mechanisms to obtain iron from heme. In this review we outline the systems that exist in several Gram-negative pathogens that are associated with heme transport and utilization, beginning with hemolysis and concluding with heme degradation. In addition, Gram-negative pathogens must also closely regulate the intracellular concentrations of iron and heme, since high levels of iron can lead to the generation of toxic reactive oxygen species. As such, we also provide several examples of regulatory pathways that control heme utilization, showing that co-regulation with other cellular processes is complex and often not completely understood.
Collapse
Affiliation(s)
- Kaylie L Richard
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Brittni R Kelley
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Jeremiah G Johnson
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| |
Collapse
|
19
|
Tanaka KJ, Pinkett HW. Oligopeptide-binding protein from nontypeable Haemophilus influenzae has ligand-specific sites to accommodate peptides and heme in the binding pocket. J Biol Chem 2018; 294:1070-1082. [PMID: 30455346 DOI: 10.1074/jbc.ra118.004479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/14/2018] [Indexed: 11/06/2022] Open
Abstract
In nontypeable Haemophilus influenzae (NTHi), the oligopeptide-binding protein (OppA) serves as the substrate-binding protein (SBP) of the oligopeptide transport system responsible for the import of peptides. We solved the crystal structure of nthiOppA in complex with hydrophobic peptides of various sizes. Our novel hexapeptide complex demonstrates the flexibility of the nthiOppA-binding cavity to expand and accommodate the longer peptide while maintaining similar protein-peptide interactions of smaller peptide complexes. In addition to acquiring peptides from the host environment, as a heme auxotroph NTHi utilizes host hemoproteins as a source of essential iron. OppA is a member of the Cluster C SBP family, and unlike other SBP families, some members recognize two distinctly different substrates. DppA (dipeptide), MppA (murein tripeptide), and SapA (antimicrobial peptides) are Cluster C proteins known to also transport heme. We observed nthiOppA shares this heme-binding characteristic and established heme specificity and affinity by surface plasmon resonance (SPR) of the four Cluster C proteins in NTHi. Ligand-docking studies predicted a distinct heme-specific cleft in the binding pocket, and using SPR competition assays, we observed that heme does not directly compete with peptide in the substrate-binding pocket. Additionally, we identified that the individual nthiOppA domains differentially contribute to substrate binding, with one domain playing a dominant role in heme binding and the other in peptide binding. Our results demonstrate the multisubstrate specificity of nthiOppA and the role of NTHi Cluster C proteins in the heme-uptake pathway for this pathogen.
Collapse
Affiliation(s)
- Kari J Tanaka
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | - Heather W Pinkett
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| |
Collapse
|
20
|
Lyles KV, Eichenbaum Z. From Host Heme To Iron: The Expanding Spectrum of Heme Degrading Enzymes Used by Pathogenic Bacteria. Front Cell Infect Microbiol 2018; 8:198. [PMID: 29971218 PMCID: PMC6018153 DOI: 10.3389/fcimb.2018.00198] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/28/2018] [Indexed: 01/02/2023] Open
Abstract
Iron is an essential nutrient for many bacteria. Since the metal is highly sequestered in host tissues, bound predominantly to heme, pathogenic bacteria often take advantage of heme uptake and degradation mechanisms to acquire iron during infection. The most common mechanism of releasing iron from heme is through oxidative degradation by heme oxygenases (HOs). In addition, an increasing number of proteins that belong to two distinct structural families have been implicated in aerobic heme catabolism. Finally, an enzyme that degrades heme anaerobically was recently uncovered, further expanding the mechanisms for bacterial heme degradation. In this analysis, we cover the spectrum and recent advances in heme degradation by infectious bacteria. We briefly explain heme oxidation by the two groups of recognized HOs to ground readers before focusing on two new types of proteins that are reported to be involved in utilization of heme iron. We discuss the structure and enzymatic function of proteins representing these groups, their biological context, and how they are regulated to provide a more complete look at their cellular role.
Collapse
Affiliation(s)
- Kristin V Lyles
- Biology, Georgia State University, Atlanta, GA, United States
| | | |
Collapse
|
21
|
Liang D, Robinson E, Hom K, Yu W, Nguyen N, Li Y, Zong Q, Wilks A, Xue F. Structure-based design and biological evaluation of inhibitors of the pseudomonas aeruginosa heme oxygenase (pa-HemO). Bioorg Med Chem Lett 2018; 28:1024-1029. [PMID: 29459206 DOI: 10.1016/j.bmcl.2018.02.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/03/2018] [Accepted: 02/13/2018] [Indexed: 02/03/2023]
Affiliation(s)
- Dongdong Liang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Elizabeth Robinson
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Kellie Hom
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Wenbo Yu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Nam Nguyen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
| | - Yue Li
- Department of Chemistry and Biochemistry, University of Maryland College Park, College Park 20740, United States
| | - Qianshou Zong
- College of Biological and Chemical Sciences and Engineering, Jiaxing University, Jiaxing City, Zhejiang 314001, People's Republic of China
| | - Angela Wilks
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States.
| | - Fengtian Xue
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States.
| |
Collapse
|
22
|
Onzuka M, Sekine Y, Uchida T, Ishimori K, Ozaki SI. HmuS from Yersinia pseudotuberculosis is a non-canonical heme-degrading enzyme to acquire iron from heme. Biochim Biophys Acta Gen Subj 2017; 1861:1870-1878. [PMID: 28385652 DOI: 10.1016/j.bbagen.2017.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/22/2017] [Accepted: 04/02/2017] [Indexed: 01/28/2023]
Abstract
Some Gram-negative pathogens import host heme into the cytoplasm and utilize it as an iron source for their survival. We report here that HmuS, encoded by the heme utilizing system (hmu) locus, cleaves the protoporphyrin ring to release iron from heme. A liquid chromatography/mass spectrometry analysis revealed that the degradation products of this reaction are two biliverdin isomers that result from transformation of a verdoheme intermediate. This oxidative heme degradation by HmuS required molecular oxygen and electrons supplied by either ascorbate or NADPH. Electrons could not be directly transferred from NADPH to heme; instead, ferredoxin-NADP+ reductase (FNR) functioned as a mediator. Although HmuS does not share amino acid sequence homology with heme oxygenase (HO), a well-known heme-degrading enzyme, absorption and resonance Raman spectral analyses suggest that the heme iron is coordinated with an axial histidine residue and a water molecule in both enzymes. The substitution of axial His196 or distal Arg102 with an alanine residue in HmuS almost completely eliminated heme-degradation activity, suggesting that Fe-His coordination and interaction of a distal residue with water molecules in the heme pocket are important for this activity.
Collapse
Affiliation(s)
- Masato Onzuka
- Department of Biological Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
| | - Yukari Sekine
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Takeshi Uchida
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Koichiro Ishimori
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shin-Ichi Ozaki
- Department of Biological Chemistry, Graduate School of Science and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
| |
Collapse
|
23
|
Ligand-induced allostery in the interaction of the Pseudomonas aeruginosa heme binding protein with heme oxygenase. Proc Natl Acad Sci U S A 2017; 114:3421-3426. [PMID: 28289188 DOI: 10.1073/pnas.1606931114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A heme-dependent conformational rearrangement of the C-terminal domain of heme binding protein (PhuS) is required for interaction with the iron-regulated heme oxygenase (HemO). Herein, we further investigate the underlying mechanism of this conformational rearrangement and its implications for heme transfer via site-directed mutagenesis, resonance Raman (RR), hydrogen-deuterium exchange MS (HDX-MS) methods, and molecular dynamics (MD). HDX-MS revealed that the apo-PhuS C-terminal α6/α7/α8-helices are largely unstructured, whereas the apo-PhuS H212R variant showed an increase in structure within these regions. The increased rate of heme association with apo-PhuS H212R compared with the WT and lack of a detectable five-coordinate high-spin (5cHS) heme intermediate are consistent with a more folded and less dynamic C-terminal domain. HDX-MS and MD of holo-PhuS indicate an overall reduction in molecular flexibility throughout the protein, with significant structural rearrangement and protection of the heme binding pocket. We observed slow cooperative unfolding/folding events within the C-terminal helices of holo-PhuS and the N-terminal α1/α2-helices that are dampened or eliminated in the holo-PhuS H212R variant. Chemical cross-linking and MALDI-TOF MS mapped these same regions to the PhuS:HemO protein-protein interface. We previously proposed that the protein-protein interaction induces conformational rearrangement, promoting a ligand switch from His-209 to His-212 and triggering heme release to HemO. The reduced conformational freedom of holo-PhuS H212R combined with the increase in entropy and decrease in heme transfer on interaction with HemO further support this model. This study provides significant insight into the role of protein dynamics in heme binding and release in bacterial heme transport proteins.
Collapse
|
24
|
Brewitz HH, Hagelueken G, Imhof D. Structural and functional diversity of transient heme binding to bacterial proteins. Biochim Biophys Acta Gen Subj 2017; 1861:683-697. [DOI: 10.1016/j.bbagen.2016.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/15/2016] [Accepted: 12/20/2016] [Indexed: 11/27/2022]
|
25
|
Vandermarliere E, Stes E, Gevaert K, Martens L. Resolution of protein structure by mass spectrometry. MASS SPECTROMETRY REVIEWS 2016; 35:653-665. [PMID: 25536908 DOI: 10.1002/mas.21450] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
Typically, mass spectrometry is used to identify the peptides present in a complex peptide mixture and subsequently the precursor proteins. As such, mass spectrometry focuses mainly on the primary structure, the (modified) amino acid sequence of peptides and proteins. In contrast, the three-dimensional structure of a protein is typically determined with protein X-ray crystallography or NMR. Despite the close relationship between these two aspects of protein studies (sequence and structure), mass spectrometry and structure determination are not frequently combined. Nevertheless, this combination of approaches, dubbed conformational proteomics, can offer insight into the function, working mechanism, and conformational status of a protein. In this review, we will discuss the developments at the intersection of mass spectrometry-based proteomics and protein structure determination and start from a brief overview of the classic approaches to identify protein structure along with their advantages and disadvantages. We will subsequently discuss the ability of mass spectrometry to overcome some of the hurdles of these classic methods. Finally, we will provide an outlook on the interplay of mass spectrometry and protein structure determination, and highlight several recent experiments in which mass spectrometry was successfully used to either aid or complement structure elucidation. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 35:653-665, 2016.
Collapse
Affiliation(s)
- Elien Vandermarliere
- Department of Medical Protein Research, VIB, B-9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, B- 9000, Ghent, Belgium
| | - Elisabeth Stes
- Department of Medical Protein Research, VIB, B-9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, B- 9000, Ghent, Belgium
| | - Kris Gevaert
- Department of Medical Protein Research, VIB, B-9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, B- 9000, Ghent, Belgium
| | - Lennart Martens
- Department of Medical Protein Research, VIB, B-9000, Ghent, Belgium.
- Department of Biochemistry, Ghent University, B- 9000, Ghent, Belgium.
| |
Collapse
|
26
|
Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
Collapse
Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
| |
Collapse
|
27
|
Mouriño S, Giardina BJ, Reyes-Caballero H, Wilks A. Metabolite-driven Regulation of Heme Uptake by the Biliverdin IXβ/δ-Selective Heme Oxygenase (HemO) of Pseudomonas aeruginosa. J Biol Chem 2016; 291:20503-15. [PMID: 27493207 DOI: 10.1074/jbc.m116.728527] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Indexed: 11/06/2022] Open
Abstract
Pseudomonas aeruginosa acquires extracellular heme via the Phu (Pseudomonas heme uptake) and Has (heme assimilation system) systems. We have previously shown the catalytic actions of heme oxygenase (HemO) along with the cytoplasmic heme transport protein PhuS control heme flux into the cell. To further investigate the role of the PhuS-HemO couple in modulating heme uptake, we have characterized two HemO variants, one that is catalytically inactive (HemO H26A/K34A/K132A or HemOin) and one that has altered regioselectivity (HemO N19K/K34A/F117Y/K132A or HemOα), producing biliverdin IXα (BVIXα). HemOα similar to wild type was able to interact and acquire heme from holo-PhuS. In contrast, the HemOin variant did not interact with holo-PhuS and showed no enzymatic activity. Complementation of a hemO deletion strain with the hemOin or hemOα variants in combination with [(13)C]heme isotopic labeling experiments revealed that the absence of BVIXβ and BVIXδ leads to a decrease in extracellular levels of hemophore HasA. We propose BVIXβ and/or BVIXδ transcriptionally or post-transcriptionally regulates HasA. Thus, coupling the PhuS-dependent flux of heme through HemO to feedback regulation of the cell surface signaling system through HasA allows P. aeruginosa to rapidly respond to fluctuating extracellular heme levels independent of the iron status of the cell.
Collapse
Affiliation(s)
- Susana Mouriño
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Bennett J Giardina
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Hermes Reyes-Caballero
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Angela Wilks
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| |
Collapse
|
28
|
Sachla AJ, Ouattara M, Romero E, Agniswamy J, Weber IT, Gadda G, Eichenbaum Z. In vitro heme biotransformation by the HupZ enzyme from Group A streptococcus. Biometals 2016; 29:593-609. [PMID: 27154580 DOI: 10.1007/s10534-016-9937-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/01/2016] [Indexed: 01/14/2023]
Abstract
In Group A streptococcus (GAS), the metallorepressor MtsR regulates iron homeostasis. Here we describe a new MtsR-repressed gene, which we named hupZ (heme utilization protein). A recombinant HupZ protein was purified bound to heme from Escherichia coli grown in the presence of 5-aminolevulinic acid and iron. HupZ specifically binds heme with stoichiometry of 1:1. The addition of NADPH to heme-bound HupZ (in the presence of cytochrome P450 reductase, NADPH-regeneration system and catalase) triggered progressive decrease of the HupZ Soret band and the appearance of an absorption peak at 660 nm that was resistance to hydrolytic conditions. No spectral changes were observed when ferredoxin and ferredoxin reductase were used as redox partners. Differential spectroscopy with myoglobin or with the ferrous chelator, ferrozine, confirmed that carbon monoxide and free iron are produced during the reaction. ApoHupZ was crystallized as a homodimer with a split β-barrel conformation in each monomer comprising six β strands and three α helices. This structure resembles the split β-barrel domain shared by the members of a recently described family of heme degrading enzymes. However, HupZ is smaller and lacks key residues found in the proteins of the latter group. Phylogenetic analysis places HupZ on a clade separated from those for previously described heme oxygenases. In summary, we have identified a new GAS enzyme-containing split β-barrel and capable of heme biotransformation in vitro; to the best of our knowledge, this is the first enzyme among Streptococcus species with such activity.
Collapse
Affiliation(s)
- Ankita J Sachla
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Mahamoudou Ouattara
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Elvira Romero
- Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA
| | - Johnson Agniswamy
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA
| | - Irene T Weber
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA
| | - Giovanni Gadda
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.,Department of Chemistry, College of Arts and Sciences, Georgia State University, Atlanta, GA, 30302-3965, USA.,Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30303, USA.,Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303, USA
| | - Zehava Eichenbaum
- Department of Biology, College of Arts and Sciences, Georgia State University, P.O. Box 4010, Atlanta, GA, 30302-4010, USA.
| |
Collapse
|
29
|
Smith AD, Wilks A. Differential contributions of the outer membrane receptors PhuR and HasR to heme acquisition in Pseudomonas aeruginosa. J Biol Chem 2015; 290:7756-66. [PMID: 25616666 DOI: 10.1074/jbc.m114.633495] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR and PhuR receptors have distinct heme coordinating ligands and substrate specificities. HasR is encoded in an operon with a secreted hemophore, HasAp. In contrast the non-hemophore-dependent PhuR is encoded within an operon along with proteins required for heme translocation into the cytoplasm. Herein we report on the contributions of the HasR and PhuR receptors to heme uptake and utilization. Employing bacterial genetics and isotopic [(13)C]heme labeling studies we have shown both PhuR and HasR are required for optimal heme utilization. However, the unique His-Tyr-ligated PhuR plays a major role in the acquisition of heme. In contrast the HasR receptor plays a primary role in the sensing of extracellular heme and a supplementary role in heme uptake. We propose PhuR and HasR represent non-redundant heme receptors, capable of accessing heme across a wide range of physiological conditions on colonization of the host.
Collapse
Affiliation(s)
- Aaron D Smith
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Angela Wilks
- From the Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| |
Collapse
|
30
|
Hogle SL, Barbeau KA, Gledhill M. Heme in the marine environment: from cells to the iron cycle. Metallomics 2015; 6:1107-20. [PMID: 24811388 DOI: 10.1039/c4mt00031e] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Hemes are iron containing heterocyclic molecules important in many cellular processes. In the marine environment, hemes participate as enzymatic cofactors in biogeochemically significant processes like photosynthesis, respiration, and nitrate assimilation. Further, hemoproteins, hemes, and their analogs appear to be iron sources for some marine bacterioplankton under certain conditions. Current oceanographic analytical methodologies allow for the extraction and measurement of heme b from marine material, and a handful of studies have begun to examine the distribution of heme b in ocean basins. The study of heme in the marine environment is still in its infancy, but some trends can be gleaned from the work that has been published so far. In this review, we summarize what is known or might be inferred about the roles of heme in marine microbes as well as the few studies on heme in the marine environment that have been conducted to date. We conclude by presenting some future questions and challenges for the field.
Collapse
Affiliation(s)
- Shane L Hogle
- Geoscience Research Division, Scripps Institution of Oceanography, La Jolla, California, USA.
| | | | | |
Collapse
|
31
|
Lee MJ, Schep D, McLaughlin B, Kaufmann M, Jia Z. Structural Analysis and Identification of PhuS as a Heme-Degrading Enzyme from Pseudomonas aeruginosa. J Mol Biol 2014; 426:1936-46. [DOI: 10.1016/j.jmb.2014.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
|
32
|
Contreras H, Chim N, Credali A, Goulding CW. Heme uptake in bacterial pathogens. Curr Opin Chem Biol 2014; 19:34-41. [PMID: 24780277 DOI: 10.1016/j.cbpa.2013.12.014] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 11/30/2022]
Abstract
Iron is an essential nutrient for the survival of organisms. Bacterial pathogens possess specialized pathways to acquire heme from their human hosts. In this review, we present recent structural and biochemical data that provide mechanistic insights into several bacterial heme uptake pathways, encompassing the sequestration of heme from human hemoproteins to secreted or membrane-associated bacterial proteins, the transport of heme across bacterial membranes, and the degradation of heme within the bacterial cytosol to liberate iron. The pathways for heme transport into the bacterial cytosol are divergent, harboring non-homologous protein sequences, novel structures, varying numbers of proteins, and different mechanisms. Congruously, the breakdown of heme within the bacterial cytosol by sequence-divergent proteins releases iron and distinct degradation products.
Collapse
Affiliation(s)
- Heidi Contreras
- Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA
| | - Nicholas Chim
- Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA
| | - Alfredo Credali
- Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA
| | - Celia W Goulding
- Department of Molecular Biology and Biochemistry, UCI, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, UCI, Irvine, CA 92697, USA.
| |
Collapse
|
33
|
Caza M, Kronstad JW. Shared and distinct mechanisms of iron acquisition by bacterial and fungal pathogens of humans. Front Cell Infect Microbiol 2013; 3:80. [PMID: 24312900 PMCID: PMC3832793 DOI: 10.3389/fcimb.2013.00080] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/30/2013] [Indexed: 12/12/2022] Open
Abstract
Iron is the most abundant transition metal in the human body and its bioavailability is stringently controlled. In particular, iron is tightly bound to host proteins such as transferrin to maintain homeostasis, to limit potential damage caused by iron toxicity under physiological conditions and to restrict access by pathogens. Therefore, iron acquisition during infection of a human host is a challenge that must be surmounted by every successful pathogenic microorganism. Iron is essential for bacterial and fungal physiological processes such as DNA replication, transcription, metabolism, and energy generation via respiration. Hence, pathogenic bacteria and fungi have developed sophisticated strategies to gain access to iron from host sources. Indeed, siderophore production and transport, iron acquisition from heme and host iron-containing proteins such as hemoglobin and transferrin, and reduction of ferric to ferrous iron with subsequent transport are all strategies found in bacterial and fungal pathogens of humans. This review focuses on a comparison of these strategies between bacterial and fungal pathogens in the context of virulence and the iron limitation that occurs in the human body as a mechanism of innate nutritional defense.
Collapse
Affiliation(s)
| | - James W. Kronstad
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada
| |
Collapse
|
34
|
Cornelis P, Dingemans J. Pseudomonas aeruginosa adapts its iron uptake strategies in function of the type of infections. Front Cell Infect Microbiol 2013; 3:75. [PMID: 24294593 PMCID: PMC3827675 DOI: 10.3389/fcimb.2013.00075] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/22/2013] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy). It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review.
Collapse
Affiliation(s)
- Pierre Cornelis
- Research Group Microbiology, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrussels, Belgium
- Department Structural Biology, VIB, Vrije Universiteit BrusselBrussels, Belgium
| | - Jozef Dingemans
- Research Group Microbiology, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrussels, Belgium
- Department Structural Biology, VIB, Vrije Universiteit BrusselBrussels, Belgium
| |
Collapse
|
35
|
Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS. J Inorg Biochem 2013; 128:131-6. [PMID: 23973453 PMCID: PMC3843485 DOI: 10.1016/j.jinorgbio.2013.07.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/19/2013] [Accepted: 07/21/2013] [Indexed: 01/07/2023]
Abstract
Iron is an essential element to all living organisms and is an important determinant of bacterial virulence. Bacteria have evolved specialized systems to sequester and transport iron from the environment or host. Pseudomonas aeruginosa, an opportunistic pathogen, uses two outer membrane receptor mediated systems (Phu and Has) to utilize host heme as a source of iron. PhuS is a 39 kDa soluble cytoplasmic heme binding protein which interacts and transports heme from the inner membrane heme transporter to the cytoplasm where it is degraded by heme oxygenase thus releasing iron. PhuS is unique among other cytoplasmic heme transporter proteins owing to the presence of three histidines in the heme binding pocket which can potentially serve as heme ligands. Out of the three histidine residues on the heme binding helix, His 209 is conserved among heme trafficking proteins while His 210 and His 212 are unique to PhuS. Here we report the crystal structure of PhuS at 1.98Å resolution which shows a unique heme binding pocket and oligomeric structure compared to other known cytoplasmic heme transporter and accounts for some of the unusual biochemical properties of PhuS.
Collapse
|
36
|
O’Neill MJ, Wilks A. The P. aeruginosa heme binding protein PhuS is a heme oxygenase titratable regulator of heme uptake. ACS Chem Biol 2013; 8:1794-802. [PMID: 23947366 DOI: 10.1021/cb400165b] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Pseudomonas aeruginosa heme utilization (Phu) system encodes several proteins involved in the acquisition of heme as an iron source. Once internalized, heme is degraded by the iron-regulated heme oxygenase, HemO to biliverdin (BV) IXδ and β. In vitro studies have shown holo-PhuS transfers heme to the iron-regulated HemO. This protein-protein interaction is specific for HemO as PhuS does not interact with the α-regioselective heme oxygenase, BphO. Bacterial genetics and isotopic labeling ((13)C-heme) studies confirmed extracellular heme is converted to (13)C-BVIX δ and β through the catalytic action of HemO. In an effort to further understand the role of PhuS, similar studies were performed on the P. aeruginosa PAO1 ΔphuS and ΔphuS/ΔhemO strains. In contrast to wild-type strain, the absence of PhuS results in extracellular heme uptake and degradation via the catalytic action of HemO and BphO. At low heme concentrations, loss of PhuS leads to inefficient extracellular heme uptake supported by the fact the mRNA levels of PhuR, HemO, and BphO remain elevated when compared to the wild-type PAO1. On increasing extracellular heme concentrations, the elevated levels of PhuR, HemO, and BphO allow "leaky uptake" and degradation of heme via HemO and BphO. Similarly, in the ΔphuS/ΔhemO strain, the higher heme concentrations combined with elevated levels of PhuR and BphO leads to nonspecific heme uptake and degradation by BphO. Thus we propose heme flux into the cell is driven by the catalytic action of HemO with PhuS acting as a "control valve" to regulate extracellular heme flux.
Collapse
Affiliation(s)
- Maura J. O’Neill
- The Department of Pharmaceutical
Sciences, School of
Pharmacy, University of Maryland, HSF II,
20 Penn Street, Baltimore, Maryland 21201-1140, United States
| | - Angela Wilks
- The Department of Pharmaceutical
Sciences, School of
Pharmacy, University of Maryland, HSF II,
20 Penn Street, Baltimore, Maryland 21201-1140, United States
| |
Collapse
|
37
|
Jutras BL, Chenail AM, Carroll DW, Miller MC, Zhu H, Bowman A, Stevenson B. Bpur, the Lyme disease spirochete's PUR domain protein: identification as a transcriptional modulator and characterization of nucleic acid interactions. J Biol Chem 2013; 288:26220-26234. [PMID: 23846702 PMCID: PMC3764826 DOI: 10.1074/jbc.m113.491357] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The PUR domain is a nucleic acid-binding motif found in critical regulatory proteins of higher eukaryotes and in certain species of bacteria. During investigations into mechanisms by which the Lyme disease spirochete controls synthesis of its Erp surface proteins, it was discovered that the borrelial PUR domain protein, Bpur, binds with high affinity to double-stranded DNA adjacent to the erp transcriptional promoter. Bpur was found to enhance the effects of the erp repressor protein, BpaB. Bpur also bound single-stranded DNA and RNA, with relative affinities RNA > double-stranded DNA > single-stranded DNA. Rational site-directed mutagenesis of Bpur identified amino acid residues and domains critical for interactions with nucleic acids, and it revealed that the PUR domain has a distinct mechanism of interaction with each type of nucleic acid ligand. These data shed light on both gene regulation in the Lyme spirochete and functional mechanisms of the widely distributed PUR domain.
Collapse
Affiliation(s)
- Brandon L Jutras
- From the Department of Microbiology, Immunology, and Molecular Genetics and
| | - Alicia M Chenail
- From the Department of Microbiology, Immunology, and Molecular Genetics and
| | - Dustin W Carroll
- the Graduate Center for Toxicology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - M Clarke Miller
- the James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky 40202, and
| | - Haining Zhu
- the Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Amy Bowman
- From the Department of Microbiology, Immunology, and Molecular Genetics and
| | - Brian Stevenson
- From the Department of Microbiology, Immunology, and Molecular Genetics and.
| |
Collapse
|
38
|
Gruss A, Borezée-Durant E, Lechardeur D. Environmental heme utilization by heme-auxotrophic bacteria. Adv Microb Physiol 2013; 61:69-124. [PMID: 23046952 DOI: 10.1016/b978-0-12-394423-8.00003-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Heme, an iron-containing porphyrin, is the prosthetic group for numerous key cellular enzymatic and regulatory processes. Many bacteria encode the biosynthetic enzymes needed for autonomous heme production. Remarkably, however, numerous other bacteria lack a complete heme biosynthesis pathway, yet encode heme-requiring functions. For such heme-auxotrophic bacteria (HAB), heme or porphyrins must be captured from the environment. Functional studies, aided by genomic analyses, provide insight into the HAB lifestyle, how they acquire and manage heme, and the uses of heme that make it worthwhile, and sometimes necessary, to capture this bioactive molecule.
Collapse
Affiliation(s)
- Alexandra Gruss
- INRA, UMR1319 Micalis and AgroParisTech, UMR Micalis, Jouy-en-Josas, France
| | | | | |
Collapse
|
39
|
Abstract
All but a few bacterial species have an absolute need for heme, and most are able to synthesize it via a pathway that is highly conserved among all life domains. Because heme is a rich source for iron, many pathogenic bacteria have also evolved processes for sequestering heme from their hosts. The heme biosynthesis pathways are well understood at the genetic and structural biology levels. In comparison, much less is known about the heme acquisition, trafficking, and degradation processes in bacteria. Gram-positive and Gram-negative bacteria have evolved similar strategies but different tactics for importing and degrading heme, likely as a consequence of their different cellular architectures. The differences are manifested in distinct structures for molecules that perform similar functions. Consequently, the aim of this chapter is to provide an overview of the structural biology of proteins and protein-protein interactions that enable Gram-positive and Gram-negative bacteria to sequester heme from the extracellular milieu, import it to the cytosol, and degrade it to mine iron.
Collapse
Affiliation(s)
- David R Benson
- Department of Chemistry, University of Kansas, Multidisciplinary Research Building, 2030 Becker Dr., Lawrence, KS, 66047, USA,
| | | |
Collapse
|
40
|
Zappa S, Bauer CE. Iron homeostasis in the Rhodobacter genus. ADVANCES IN BOTANICAL RESEARCH 2013; 66:10.1016/B978-0-12-397923-0.00010-2. [PMID: 24382933 PMCID: PMC3875232 DOI: 10.1016/b978-0-12-397923-0.00010-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Metals are utilized for a variety of critical cellular functions and are essential for survival. However cells are faced with the conundrum of needing metals coupled with e fact that some metals, iron in particular are toxic if present in excess. Maintaining metal homeostasis is therefore of critical importance to cells. In this review we have systematically analyzed sequenced genomes of three members of the Rhodobacter genus, R. capsulatus SB1003, R. sphaeroides 2.4.1 and R. ferroxidans SW2 to determine how these species undertake iron homeostasis. We focused our analysis on elemental ferrous and ferric iron uptake genes as well as genes involved in the utilization of iron from heme. We also discuss how Rhodobacter species manage iron toxicity through export and sequestration of iron. Finally we discuss the various putative strategies set up by these Rhodobacter species to regulate iron homeostasis and the potential novel means of regulation. Overall, this genomic analysis highlights surprisingly diverse features involved in iron homeostasis in the Rhodobacter genus.
Collapse
Affiliation(s)
- Sébastien Zappa
- Department of Molecular and Cellular Biochemistry, Indiana University, Simon Hall, 212 S Hawthorne Dr, Bloomington, IN 47405, U. S. A
| | - Carl E. Bauer
- Department of Molecular and Cellular Biochemistry, Indiana University, Simon Hall, 212 S Hawthorne Dr, Bloomington, IN 47405, U. S. A
| |
Collapse
|