1
|
Mahoney BJ, Goring AK, Wang Y, Dasika P, Zhou A, Grossbard E, Cascio D, Loo JA, Clubb RT. Development and atomic structure of a new fluorescence-based sensor to probe heme transfer in bacterial pathogens. J Inorg Biochem 2023; 249:112368. [PMID: 37729854 DOI: 10.1016/j.jinorgbio.2023.112368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/11/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023]
Abstract
Heme is the most abundant source of iron in the human body and is actively scavenged by bacterial pathogens during infections. Corynebacterium diphtheriae and other species of actinobacteria scavenge heme using cell wall associated and secreted proteins that contain Conserved Region (CR) domains. Here we report the development of a fluorescent sensor to measure heme transfer from the C-terminal CR domain within the HtaA protein (CR2) to other hemoproteins within the heme-uptake system. The sensor contains the CR2 domain inserted into the β2 to β3 turn of the Enhanced Green Fluorescent Protein (EGFP). A 2.45 Å crystal structure reveals the basis of heme binding to the CR2 domain via iron-tyrosyl coordination and shares conserved structural features with CR domains present in Corynebacterium glutamicum. The structure and small angle X-ray scattering experiments are consistent with the sensor adopting a V-shaped structure that exhibits only small fluctuations in inter-domain positioning. We demonstrate heme transfer from the sensor to the CR domains located within the HtaA or HtaB proteins in the heme-uptake system as measured by a ∼ 60% increase in sensor fluorescence and native mass spectrometry.
Collapse
Affiliation(s)
- Brendan J Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Andrew K Goring
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Yueying Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Poojita Dasika
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Anqi Zhou
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Emmitt Grossbard
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
| |
Collapse
|
2
|
Macdonald R, Mahoney BJ, Soule J, Goring AK, Ford J, Loo JA, Cascio D, Clubb RT. The Shr receptor from Streptococcus pyogenes uses a cap and release mechanism to acquire heme-iron from human hemoglobin. Proc Natl Acad Sci U S A 2023; 120:e2211939120. [PMID: 36693107 PMCID: PMC9945957 DOI: 10.1073/pnas.2211939120] [Citation(s) in RCA: 1] [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: 07/22/2022] [Accepted: 12/19/2022] [Indexed: 01/25/2023] Open
Abstract
Streptococcus pyogenes (group A Streptococcus) is a clinically important microbial pathogen that requires iron in order to proliferate. During infections, S. pyogenes uses the surface displayed Shr receptor to capture human hemoglobin (Hb) and acquires its iron-laden heme molecules. Through a poorly understood mechanism, Shr engages Hb via two structurally unique N-terminal Hb-interacting domains (HID1 and HID2) which facilitate heme transfer to proximal NEAr Transporter (NEAT) domains. Based on the results of X-ray crystallography, small angle X-ray scattering, NMR spectroscopy, native mass spectrometry, and heme transfer experiments, we propose that Shr utilizes a "cap and release" mechanism to gather heme from Hb. In the mechanism, Shr uses the HID1 and HID2 modules to preferentially recognize only heme-loaded forms of Hb by contacting the edges of its protoporphyrin rings. Heme transfer is enabled by significant receptor dynamics within the Shr-Hb complex which function to transiently uncap HID1 from the heme bound to Hb's β subunit, enabling the gated release of its relatively weakly bound heme molecule and subsequent capture by Shr's NEAT domains. These dynamics may maximize the efficiency of heme scavenging by S. pyogenes, enabling it to preferentially recognize and remove heme from only heme-loaded forms of Hb that contain iron.
Collapse
Affiliation(s)
- Ramsay Macdonald
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
| | - Brendan J. Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
- University of California, Los Angeles-United States Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA90095
| | - Jess Soule
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
| | - Andrew K. Goring
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
| | - Jordan Ford
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
- University of California, Los Angeles-United States Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA90095
- Molecular Biology Institute, University of California, Los Angeles, CA90095
| | - Duilio Cascio
- University of California, Los Angeles-United States Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA90095
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA90095
- University of California, Los Angeles-United States Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA90095
- Molecular Biology Institute, University of California, Los Angeles, CA90095
| |
Collapse
|
3
|
Chatterjee N, Huang YS, Lyles KV, Morgan JE, Kauvar LM, Greer SF, Eichenbaum Z. Native Human Antibody to Shr Promotes Mice Survival After Intraperitoneal Challenge With Invasive Group A Streptococcus. J Infect Dis 2021; 223:1367-1375. [PMID: 32845315 DOI: 10.1093/infdis/jiaa540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/20/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A vaccine against group A Streptococcus (GAS) has been actively pursued for decades. The surface receptor Shr is vital in GAS heme uptake and provides an effective target for active and passive immunization. Here, we isolated human monoclonal antibodies (mAbs) against Shr and evaluated their efficacy and mechanism. METHODS We used a single B-lymphocyte screen to discover the mAbs TRL186 and TRL96. Interactions of the mAbs with whole cells, proteins, and peptides were investigated. Growth assays and cultured phagocytes were used to study the mAbs' impact on heme uptake and bacterial killing. Efficacy was tested in prophylactic and therapeutic vaccination using intraperitoneal mAb administration and GAS challenge. RESULTS Both TRL186 and TRL96 interact with whole GAS cells, recognizing the NTR and NEAT1 domains of Shr, respectively. Both mAbs promoted killing by phagocytes in vitro, but prophylactic administration of only TRL186 increased mice survival. TRL186 improved survival also in a therapeutic mode. TRL186 but not TRL96 also impeded Shr binding to hemoglobin and GAS growth on hemoglobin iron. CONCLUSIONS Interference with iron acquisition is central for TRL186 efficacy against GAS. This study supports the concept of antibody-based immunotherapy targeting the heme uptake proteins to combat streptococcal infections.
Collapse
Affiliation(s)
| | - Ya-Shu Huang
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Kristin V Lyles
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Julie E Morgan
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | | | - Susanna F Greer
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Zehava Eichenbaum
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| |
Collapse
|
4
|
Active and passive immunizations with HtsA, a streptococcal heme transporter protein, protect mice from subcutaneous group A Streptococcus infection. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2020; 53:87-93. [PMID: 29807723 DOI: 10.1016/j.jmii.2018.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/26/2017] [Accepted: 03/15/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND/PURPOSE HtsA (Streptococcus heme transporter A) is the lipoprotein component of the streptococcal heme ABC transporter (HtsABC). The aim of this study is to investigate whether the HtsA protein has immunoprotective effect against group A Streptococcus (GAS) infection in mice. METHODS The HtsA protein was purified by sequential chromatography on Ni-sepharose, DEAE-sepharose and Phenyl-sepharose, CD-1 mice were actively immunized with ALUM (control) or HtsA/ALUM, and passively immunized with control or anti-HtsA serum. Mice were challenged with GAS after immunization, and the survival rate, skin lesion size and systemic GAS dissemination were determined. RESULTS The HtsA gene was cloned, and the recombinant protein HtsA was successfully purified. HtsA has a strong antigenicity, and active immunization with the HtsA protein significantly protected mice against lethal subcutaneous GAS infection, inhibited invasion of the skin by GAS, and reduced GAS systemic dissemination in blood and organs. In addition, passive immunization with anti-HtsA serum also significantly protected mice against subcutaneous GAS infection, and inhibited invasion of the skin by GAS. CONCLUSION The results showed that both active and passive immunization with the HtsA protein protected mice against subcutaneous GAS infection, suggesting that HtsA may be a candidate of GAS vaccine to protect against GAS infection.
Collapse
|
5
|
Macdonald R, Cascio D, Collazo MJ, Phillips M, Clubb RT. The Streptococcus pyogenes Shr protein captures human hemoglobin using two structurally unique binding domains. J Biol Chem 2018; 293:18365-18377. [PMID: 30301765 DOI: 10.1074/jbc.ra118.005261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/03/2018] [Indexed: 12/19/2022] Open
Abstract
In order to proliferate and mount an infection, many bacterial pathogens need to acquire iron from their host. The most abundant iron source in the body is the oxygen transporter hemoglobin (Hb). Streptococcus pyogenes, a potentially lethal human pathogen, uses the Shr protein to capture Hb on the cell surface. Shr is an important virulence factor, yet the mechanism by which it captures Hb and acquires its heme is not well-understood. Here, we show using NMR and biochemical methods that Shr binds Hb using two related modules that were previously defined as domains of unknown function (DUF1533). These hemoglobin-interacting domains (HIDs), called HID1 and HID2, are autonomously folded and independently bind Hb. The 1.5 Å resolution crystal structure of HID2 revealed that it is a structurally unique Hb-binding domain. Mutagenesis studies revealed a conserved tyrosine in both HIDs that is essential for Hb binding. Our biochemical studies indicate that HID2 binds Hb with higher affinity than HID1 and that the Hb tetramer is engaged by two Shr receptors. NMR studies reveal the presence of a third autonomously folded domain between HID2 and a heme-binding NEAT1 domain, suggesting that this linker domain may position NEAT1 near Hb for heme capture.
Collapse
Affiliation(s)
- Ramsay Macdonald
- From the Department of Chemistry and Biochemistry,; UCLA-DOE Institute of Genomics and Proteomics and
| | | | | | | | - Robert T Clubb
- From the Department of Chemistry and Biochemistry,; UCLA-DOE Institute of Genomics and Proteomics and; Molecular Biology Institute, UCLA, Los Angeles, California 90095.
| |
Collapse
|
6
|
Song Y, Zhang X, Cai M, Lv C, Zhao Y, Wei D, Zhu H. The Heme Transporter HtsABC of Group A Streptococcus Contributes to Virulence and Innate Immune Evasion in Murine Skin Infections. Front Microbiol 2018; 9:1105. [PMID: 29887858 PMCID: PMC5981463 DOI: 10.3389/fmicb.2018.01105] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/08/2018] [Indexed: 02/06/2023] Open
Abstract
Group A Streptococcus (GAS) requires iron for growth, and heme is an important source of iron for GAS. Streptococcus heme transporter A (HtsA) is the lipoprotein component of the GAS heme-specific ABC transporter (HtsABC). The objective of this study is to examine the contribution of HtsABC to virulence and host interaction of hypervirulent M1T1 GAS using an isogenic htsA deletion mutant (ΔhtsA). The htsA deletion exhibited a significantly increased survival rate, reduced skin lesion size, and reduced systemic GAS dissemination in comparison to the wild type strain. The htsA deletion also decreased the GAS adhesion rate to Hep-2 cells, the survival in human blood and rat neutrophils, and increased the production of cytokine IL-1β, IL-6, and TNF-α levels in air pouch exudate of a mouse model of subcutaneous infection. Complementation of ΔhtsA restored the wild type phenotype. These findings support that the htsA gene is required for GAS virulence and that the htsA deletion augments host innate immune responses.
Collapse
Affiliation(s)
- Yingli Song
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Xiaolan Zhang
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Minghui Cai
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Chunmei Lv
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Yuan Zhao
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Deqin Wei
- Department of Physiology, Harbin Medical University, Harbin, China
| | - Hui Zhu
- Department of Physiology, Harbin Medical University, Harbin, China
| |
Collapse
|
7
|
Brouwer S, Barnett TC, Rivera-Hernandez T, Rohde M, Walker MJ. Streptococcus pyogenes adhesion and colonization. FEBS Lett 2016; 590:3739-3757. [PMID: 27312939 DOI: 10.1002/1873-3468.12254] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/10/2016] [Accepted: 06/13/2016] [Indexed: 12/19/2022]
Abstract
Streptococcus pyogenes (group A Streptococcus, GAS) is a human-adapted pathogen responsible for a wide spectrum of disease. GAS can cause relatively mild illnesses, such as strep throat or impetigo, and less frequent but severe life-threatening diseases such as necrotizing fasciitis and streptococcal toxic shock syndrome. GAS is an important public health problem causing significant morbidity and mortality worldwide. The main route of GAS transmission between humans is through close or direct physical contact, and particularly via respiratory droplets. The upper respiratory tract and skin are major reservoirs for GAS infections. The ability of GAS to establish an infection in the new host at these anatomical sites primarily results from two distinct physiological processes, namely bacterial adhesion and colonization. These fundamental aspects of pathogenesis rely upon a variety of GAS virulence factors, which are usually under strict transcriptional regulation. Considerable progress has been made in better understanding these initial infection steps. This review summarizes our current knowledge of the molecular mechanisms of GAS adhesion and colonization.
Collapse
Affiliation(s)
- Stephan Brouwer
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Timothy C Barnett
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre For Infection Research, Braunschweig, Germany
| | - Mark J Walker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| |
Collapse
|
8
|
Abstract
Gram-positive Streptococcus species are responsible for millions of cases of meningitis, bacterial pneumonia, endocarditis, erysipelas and necrotizing fasciitis. Iron is essential for the growth and survival of Streptococcus in the host environment. Streptococcus species have developed various mechanisms to uptake iron from an environment with limited available iron. Streptococcus can directly extract iron from host iron-containing proteins such as ferritin, transferrin, lactoferrin and hemoproteins, or indirectly by relying on the employment of specialized secreted hemophores (heme chelators) and small siderophore molecules (high affinity ferric chelators). This review presents the most recent discoveries in the iron acquisition system of Streptococcus species - the transporters as well as the regulators.
Collapse
Affiliation(s)
- Ruiguang Ge
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| | | |
Collapse
|
9
|
Non-heme-binding domains and segments of the Staphylococcus aureus IsdB protein critically contribute to the kinetics and equilibrium of heme acquisition from methemoglobin. PLoS One 2014; 9:e100744. [PMID: 24959723 PMCID: PMC4069089 DOI: 10.1371/journal.pone.0100744] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/28/2014] [Indexed: 11/19/2022] Open
Abstract
The hemoglobin receptor IsdB rapidly acquires heme from methemoglobin (metHb) in the heme acquisition pathway of Staphylococcus aureus. IsdB consists of N-terminal segment (NS), NEAT1 (N1), middle (MD), and heme binding NEAT2 (N2) domains, and C-terminal segment (CS). This study aims to elucidate the roles of these domains or segments in the metHb/IsdB reaction. Deletion of CS does not alter the kinetics and equilibrium of the reaction. Sequential deletions of NS and N1 in NS-N1-MD-N2 progressively reduce heme transfer rates and change the kinetic pattern from one to two phases, but have no effect on the equilibrium of the heme transfer reaction, whereas further deletion of MD reduces the percentage of transferred metHb heme. MD-N2 has higher affinity for heme than N2. MD in trans reduces rates of heme dissociation from holo-N2 and increases the percentage of metHb heme captured by N2 by 4.5 fold. NS-N1-MD and N2, but not NS-N1, MD, and N2, reconstitute the rapid metHb/IsdB reaction. NS-N1-MD-NIsdC, a fusion protein of NS-N1-MD and the NEAT domain of IsdC, slowly acquires heme from metHb by itself but together with N2 results in rapid heme loss from metHb. Thus, NS-N1 and MD domains specifically and critically contribute to the kinetics and equilibrium of the metHb/IsdB reaction, respectively. These findings support a mechanism of direct heme acquisition by IsdB in which MD enhances the affinity of N2 for heme to thermodynamically drive heme transfer from metHb to IsdB and in which NS is required for the rapid and single phase kinetics of the metHb/IsdB reaction.
Collapse
|
10
|
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: 178] [Impact Index Per Article: 16.2] [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
|
11
|
Ran Y, Malmirchegini GR, Clubb RT, Lei B. Axial ligand replacement mechanism in heme transfer from streptococcal heme-binding protein Shp to HtsA of the HtsABC transporter. Biochemistry 2013; 52:6537-47. [PMID: 23980583 PMCID: PMC3815476 DOI: 10.1021/bi400965u] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The heme-binding protein Shp of Group A Streptococcus rapidly transfers its heme to HtsA, the lipoprotein component of the HtsABC transporter, in a concerted two-step process with one kinetic phase. Heme axial residue-to-alanine replacement mutant proteins of Shp and HtsA (Shp(M66A), Shp(M153A), HtsA(M79A), and HtsA(H229A)) were used to probe the axial displacement mechanism of this heme transfer reaction. Ferric Shp(M66A) at high pH and Shp(M153A) have a pentacoordinate heme iron complex with a methionine axial ligand. ApoHtsA(M79A) efficiently acquires heme from ferric Shp but alters the reaction mechanism to two kinetic phases from a single phase in the wild-type protein reactions. In contrast, apoHtsA(H229A) cannot assimilate heme from ferric Shp. The conversion of pentacoordinate holoShp(M66A) into pentacoordinate holoHtsA(H229A) involves an intermediate, whereas holoHtsA(H229A) is directly formed from pentacoordinate holoShp(M153A). Conversely, apoHtsA(M79A) reacts with holoShp(M66A) and holoShp(M153A) in mechanisms with one and two kinetic phases, respectively. These results imply that the Met79 and His229 residues of HtsA displace the Met66 and Met153 residues of Shp, respectively. Structural docking analysis supports this mechanism of the specific axial residue displacement. Furthermore, the rates of the cleavage of the axial bond in Shp in the presence of a replacing HtsA axial residue are greater than that in the absence of a replacing HtsA axial residue. These findings reveal a novel heme transfer mechanism of the specific displacement of the Shp axial residues with the HtsA axial residues and the involvement of the HtsA axial residues in the displacement.
Collapse
Affiliation(s)
- Yanchao Ran
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, MT 59718
| | - G. Reza Malmirchegini
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Benfang Lei
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, MT 59718
| |
Collapse
|
12
|
Ouattara M, Pennati A, Devlin DJ, Huang YS, Gadda G, Eichenbaum Z. Kinetics of heme transfer by the Shr NEAT domains of Group A Streptococcus. Arch Biochem Biophys 2013; 538:71-9. [PMID: 23993953 DOI: 10.1016/j.abb.2013.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/06/2013] [Accepted: 08/14/2013] [Indexed: 01/07/2023]
Abstract
The hemolytic Group A Streptococcus (GAS) is a notorious human pathogen. Shr protein of GAS participates in iron acquisition by obtaining heme from host hemoglobin and delivering it to the adjacent receptor on the surface, Shp. Heme is then conveyed to the SiaABC proteins for transport across the membrane. Using rapid kinetic studies, we investigated the role of the two heme binding NEAT modules of Shr. Stopped-flow analysis showed that holoNEAT1 quickly delivered heme to apoShp. HoloNEAT2 did not exhibit such activity; only little and slow transfer of heme from NEAT2 to apoShp was seen, suggesting that Shr NEAT domains have distinctive roles in heme transport. HoloNEAT1 also provided heme to apoNEAT2, by a fast and reversible process. To the best of our knowledge this is the first transfer observed between isolated NEAT domains of the same receptor. Sequence alignment revealed that Shr NEAT domains belong to two families of NEAT domains that are conserved in Shr orthologs from several species. Based on the heme transfer kinetics, we propose that Shr proteins modulate heme uptake according to heme availability by a mechanism where NEAT1 facilitates fast heme delivery to Shp, whereas NEAT2 serves as a temporary storage for heme on the bacterial surface.
Collapse
Affiliation(s)
- Mahamoudou Ouattara
- Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, GA 30303, USA
| | | | | | | | | | | |
Collapse
|
13
|
Spirig T, Malmirchegini GR, Zhang J, Robson SA, Sjodt M, Liu M, Krishna Kumar K, Dickson CF, Gell DA, Lei B, Loo JA, Clubb RT. Staphylococcus aureus uses a novel multidomain receptor to break apart human hemoglobin and steal its heme. J Biol Chem 2012; 288:1065-78. [PMID: 23132864 DOI: 10.1074/jbc.m112.419119] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Staphylococcus aureus is a leading cause of life-threatening infections in the United States. It requires iron to grow, which must be actively procured from its host to successfully mount an infection. Heme-iron within hemoglobin (Hb) is the most abundant source of iron in the human body and is captured by S. aureus using two closely related receptors, IsdH and IsdB. Here we demonstrate that each receptor captures heme using two conserved near iron transporter (NEAT) domains that function synergistically. NMR studies of the 39-kDa conserved unit from IsdH (IsdH(N2N3), Ala(326)-Asp(660)) reveals that it adopts an elongated dumbbell-shaped structure in which its NEAT domains are properly positioned by a helical linker domain, whose three-dimensional structure is determined here in detail. Electrospray ionization mass spectrometry and heme transfer measurements indicate that IsdH(N2N3) extracts heme from Hb via an ordered process in which the receptor promotes heme release by inducing steric strain that dissociates the Hb tetramer. Other clinically significant Gram-positive pathogens capture Hb using receptors that contain multiple NEAT domains, suggesting that they use a conserved mechanism.
Collapse
Affiliation(s)
- Thomas Spirig
- Department of Chemistry and Biochemistry and the UCLA-Department of Energy Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|