1
|
Lorenzi M, Sylvi L, Gerbaud G, Mileo E, Halgand F, Walburger A, Vezin H, Belle V, Guigliarelli B, Magalon A. Conformational selection underlies recognition of a molybdoenzyme by its dedicated chaperone. PLoS One 2012. [PMID: 23185350 PMCID: PMC3501500 DOI: 10.1371/journal.pone.0049523] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Molecular recognition is central to all biological processes. Understanding the key role played by dedicated chaperones in metalloprotein folding and assembly requires the knowledge of their conformational ensembles. In this study, the NarJ chaperone dedicated to the assembly of the membrane-bound respiratory nitrate reductase complex NarGHI, a molybdenum-iron containing metalloprotein, was taken as a model of dedicated chaperone. The combination of two techniques ie site-directed spin labeling followed by EPR spectroscopy and ion mobility mass spectrometry, was used to get information about the structure and conformational dynamics of the NarJ chaperone upon binding the N-terminus of the NarG metalloprotein partner. By the study of singly spin-labeled proteins, the E119 residue present in a conserved elongated hydrophobic groove of NarJ was shown to be part of the interaction site. Moreover, doubly spin-labeled proteins studied by pulsed double electron-electron resonance (DEER) spectroscopy revealed a large and composite distribution of inter-label distances that evolves into a single preexisting one upon complex formation. Additionally, ion mobility mass spectrometry experiments fully support these findings by revealing the existence of several conformers in equilibrium through the distinction of different drift time curves and the selection of one of them upon complex formation. Taken together our work provides a detailed view of the structural flexibility of a dedicated chaperone and suggests that the exquisite recognition and binding of the N-terminus of the metalloprotein is governed by a conformational selection mechanism.
Collapse
Affiliation(s)
- Magali Lorenzi
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Léa Sylvi
- Laboratoire de Chimie Bactérienne (UMR7283), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Guillaume Gerbaud
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Elisabetta Mileo
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Frédéric Halgand
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Anne Walburger
- Laboratoire de Chimie Bactérienne (UMR7283), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Hervé Vezin
- Laboratoire de Spectrochimie Infrarouge et Raman (UMR8516), Villeneuve d'Ascq, France
| | - Valérie Belle
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
- * E-mail: (VB); (AM)
| | - Bruno Guigliarelli
- Unité de Bioénergétique et Ingénierie des Protéines (UMR7281), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
| | - Axel Magalon
- Laboratoire de Chimie Bactérienne (UMR7283), Institut de Microbiologie de la Méditerranée, CNRS & Aix-Marseille Univ, Marseille, France
- * E-mail: (VB); (AM)
| |
Collapse
|
2
|
Direct visualization reveals dynamics of a transient intermediate during protein assembly. Proc Natl Acad Sci U S A 2011; 108:6450-5. [PMID: 21464281 DOI: 10.1073/pnas.1019051108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Interactions between proteins underlie numerous biological functions. Theoretical work suggests that protein interactions initiate with formation of transient intermediates that subsequently relax to specific, stable complexes. However, the nature and roles of these transient intermediates have remained elusive. Here, we characterized the global structure, dynamics, and stability of a transient, on-pathway intermediate during complex assembly between the Signal Recognition Particle (SRP) and its receptor. We show that this intermediate has overlapping but distinct interaction interfaces from that of the final complex, and it is stabilized by long-range electrostatic interactions. A wide distribution of conformations is explored by the intermediate; this distribution becomes more restricted in the final complex and is further regulated by the cargo of SRP. These results suggest a funnel-shaped energy landscape for protein interactions, and they provide a framework for understanding the role of transient intermediates in protein assembly and biological regulation.
Collapse
|