Modulation by Substrates of the Interaction between the HasR Outer Membrane Receptor and Its Specific TonB-like Protein, HasB

Lefèvre, Julien; Delepelaire, Philippe; Delepierre, Muriel; Izadi-Pruneyre, Nadia

doi:10.1016/j.jmb.2008.03.044

Cited by 27 publications

(36 citation statements)

References 51 publications

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“…The HasR outer membrane receptor/transporter from Serratia marcescens interacts specifically with the TonB-like protein HasB, driving import of heme across the outer membrane. The binding of extracellular substrates like heme and hemophores (HasA) to HasR alters the interaction between the transporter (HasR) and the globular C-terminal domain of HasB, suggesting that protein-protein interactions on the outer membrane relay signals to the periplasm, permitting heme transport [21] Another recently characterized outer membrane receptor, ShuA ( Shigella dysenteriae ), has two histidines mediating heme binding/release. The protein interacts with the TonB transporter with 1:1 stoichiometry [22•].…”

Section: Starting At the Beginning: Heme Uptake And Traffickingmentioning

confidence: 99%

Recent advances in bacterial heme protein biochemistry

Mayfield

Dehner

DuBois

2011

Current Opinion in Chemical Biology

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Section: Starting At the Beginning: Heme Uptake And Traffickingmentioning

confidence: 99%

Recent advances in bacterial heme protein biochemistry

Mayfield

Dehner

DuBois

2011

Current Opinion in Chemical Biology

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“…In order to determine the basis of the specificity of HasB for HasR, we studied, in a previous work [20], the in vitro interaction of HasR with HasB CTD (HasB C-terminal domain) , a periplasmic fragment of HasB (residues 133–263, formerly named HasB 133 ) and compared it with that of an equivalent domain of E. coli TonB (TonB CTD , previously named TonB 116 ). We have demonstrated that while TonB CTD (TonB C-terminal domain) behaves as a “generalist energy transducer” interacting within the same range of affinity and with wide range of TBDTs, the HasB-HasR interaction presents a higher affinity (K d = 13 nM) and a different interaction network [20].…”

Section: Introductionmentioning

confidence: 99%

“…We have demonstrated that while TonB CTD (TonB C-terminal domain) behaves as a “generalist energy transducer” interacting within the same range of affinity and with wide range of TBDTs, the HasB-HasR interaction presents a higher affinity (K d = 13 nM) and a different interaction network [20]. Having observed the difference of binding mode between HasB and TonB, we wondered whether it is due to structural differences between the two proteins and/or to the fact that they do not recognize the same region of HasR.…”

Section: Introductionmentioning

confidence: 99%

The Structure of HasB Reveals a New Class of TonB Protein Fold

et al. 2013

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TonB is a key protein in active transport of essential nutrients like vitamin B12 and metal sources through the outer membrane transporters of Gram-negative bacteria. This inner membrane protein spans the periplasm, contacts the outer membrane receptor by its periplasmic domain and transduces energy from the cytoplasmic membrane pmf to the receptor allowing nutrient internalization. Whereas generally a single TonB protein allows the acquisition of several nutrients through their cognate receptor, in some species one particular TonB is dedicated to a specific system. Despite a considerable amount of data available, the molecular mechanism of TonB-dependent active transport is still poorly understood. In this work, we present a structural study of a TonB-like protein, HasB dedicated to the HasR receptor. HasR acquires heme either free or via an extracellular heme transporter, the hemophore HasA. Heme is used as an iron source by bacteria. We have solved the structure of the HasB periplasmic domain of Serratia marcescens and describe its interaction with a critical region of HasR. Some important differences are observed between HasB and TonB structures. The HasB fold reveals a new structural class of TonB-like proteins. Furthermore, we have identified the structural features that explain the functional specificity of HasB. These results give a new insight into the molecular mechanism of nutrient active transport through the bacterial outer membrane and present the first detailed structural study of a specific TonB-like protein and its interaction with the receptor.

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“…This may be related to the strong affinity of the C-terminus of HasB for HasR, which is more than 50 times higher than the affinity of the C-terminus of TonB E.c for HasR (Lefevre et al, 2008). This higher affinity may be related to the fact that, along with the TonB box, other regions of HasR are involved in the interaction with HasB (Lefevre et al, 2008). These regions could be specifically involved in the signal transduction process.…”

Section: Discussionmentioning

confidence: 99%

The Hem and Has haem uptake systems in Serratia marcescens

Benevides-Matos

Biville

2010

Microbiology

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Serratia marcescens, like several other Gram-negative bacteria, possesses two functional haem uptake systems. The first, referred to as the Hem system, can transport haem present at a concentration equal to or above 10 "6 M. It requires an active outer-membrane receptor which uses proton-motive force energy transmitted by the inner-membrane TonB protein. The other system, Has, takes up haem at lower concentrations and utilizes a small secreted haem-binding protein (haemophore) and its cognate TonB-dependent outer-membrane receptor HasR. Various combinations of mutations were used to examine haem uptake activity by the two systems in S. marcescens. The Hem uptake system enables S. marcescens to take up haem at a concentration of 10 "6 M in the presence of various levels of iron depletion. The Has system, which enables such uptake even in the presence of lower haem concentrations, requires higher iron depletion conditions for function. Has haem uptake requires the presence of HasB, a TonB paralogue encoded by the has operon. These two systems enable S. marcescens to take up haem under various conditions from different sources, reflecting its capacity to confront conditions encountered in natural biotopes.

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Modulation by Substrates of the Interaction between the HasR Outer Membrane Receptor and Its Specific TonB-like Protein, HasB

Cited by 27 publications

References 51 publications

Recent advances in bacterial heme protein biochemistry

Recent advances in bacterial heme protein biochemistry

The Structure of HasB Reveals a New Class of TonB Protein Fold

The Hem and Has haem uptake systems in Serratia marcescens

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