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  1. Article ; Online: Conservation and divergence of the G-interfaces of Drosophila melanogaster septins.

    de Freitas Fernandes, Adriano / Leonardo, Diego Antonio / Cavini, Italo Augusto / Rosa, Higor Vinícius Dias / Vargas, Jhon Antoni / D'Muniz Pereira, Humberto / Nascimento, Alessandro S / Garratt, Richard Charles

    Cytoskeleton (Hoboken, N.J.)

    2023  Volume 80, Issue 7-8, Page(s) 153–168

    Abstract: Septins possess a conserved guanine nucleotide-binding (G) domain that participates in the stabilization of organized hetero-oligomeric complexes which assemble into filaments, rings and network-like structures. The fruit fly, Drosophila melanogaster, ... ...

    Abstract Septins possess a conserved guanine nucleotide-binding (G) domain that participates in the stabilization of organized hetero-oligomeric complexes which assemble into filaments, rings and network-like structures. The fruit fly, Drosophila melanogaster, has five such septin genes encoding Sep1, Sep2, Sep4, Sep5 and Pnut. Here, we report the crystal structure of the heterodimer formed between the G-domains of Sep1 and Sep2, the first from an insect to be described to date. A G-interface stabilizes the dimer (in agreement with the expected arrangement for the Drosophila hexameric particle) and this bears significant resemblance to its human counterparts, even down to the level of individual amino acid interactions. On the other hand, a model for the G-interface formed between the two copies of Pnut which occupy the centre of the hexamer, shows important structural differences, including the loss of a highly favourable bifurcated salt-bridge network. Whereas wild-type Pnut purifies as a monomer, the reintroduction of the salt-bridge network results in stabilizing the dimeric interface in solution as shown by size exclusion chromatography and thermal stability measurements. Adaptive steered molecular dynamics reveals an unzipping mechanism for dimer dissociation which initiates at a point of electrostatic repulsion within the switch II region. Overall, the data contribute to a better understanding of the molecular interactions involved in septin assembly/disassembly.
    Language English
    Publishing date 2023-01-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2534372-5
    ISSN 1949-3592 ; 1949-3584
    ISSN (online) 1949-3592
    ISSN 1949-3584
    DOI 10.1002/cm.21740
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Molecular Recognition at Septin Interfaces: The Switches Hold the Key.

    Rosa, Higor Vinícius Dias / Leonardo, Diego Antonio / Brognara, Gabriel / Brandão-Neto, José / D'Muniz Pereira, Humberto / Araújo, Ana Paula Ulian / Garratt, Richard Charles

    Journal of molecular biology

    2020  Volume 432, Issue 21, Page(s) 5784–5801

    Abstract: The assembly of a septin filament requires that homologous monomers must distinguish between one another in establishing appropriate interfaces with their neighbors. To understand this phenomenon at the molecular level, we present the first four crystal ... ...

    Abstract The assembly of a septin filament requires that homologous monomers must distinguish between one another in establishing appropriate interfaces with their neighbors. To understand this phenomenon at the molecular level, we present the first four crystal structures of heterodimeric septin complexes. We describe in detail the two distinct types of G-interface present within the octameric particles, which must polymerize to form filaments. These are formed between SEPT2 and SEPT6 and between SEPT7 and SEPT3, and their description permits an understanding of the structural basis for the selectivity necessary for correct filament assembly. By replacing SEPT6 by SEPT8 or SEPT11, it is possible to rationalize Kinoshita's postulate, which predicts the exchangeability of septins from within a subgroup. Switches I and II, which in classical small GTPases provide a mechanism for nucleotide-dependent conformational change, have been repurposed in septins to play a fundamental role in molecular recognition. Specifically, it is switch I which holds the key to discriminating between the two different G-interfaces. Moreover, residues which are characteristic for a given subgroup play subtle, but pivotal, roles in guaranteeing that the correct interfaces are formed.
    MeSH term(s) Cell Cycle Proteins/chemistry ; Cell Cycle Proteins/metabolism ; Crystallography, X-Ray ; Humans ; Models, Molecular ; Monomeric GTP-Binding Proteins/chemistry ; Monomeric GTP-Binding Proteins/metabolism ; Protein Binding ; Protein Conformation ; Protein Interaction Maps ; Protein Multimerization ; Septins/chemistry ; Septins/metabolism
    Chemical Substances Cell Cycle Proteins ; SEPTIN11 protein, human (EC 3.6.1.-) ; SEPTIN2 protein, human (EC 3.6.1.-) ; SEPTIN6 protein, human (EC 3.6.1.-) ; SEPTIN7 protein, human (EC 3.6.1.-) ; SEPTIN8 protein, human (EC 3.6.1.-) ; Septins (EC 3.6.1.-) ; septin 3 (EC 3.6.1.-) ; Monomeric GTP-Binding Proteins (EC 3.6.5.2)
    Language English
    Publishing date 2020-09-07
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2020.09.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Molecular Recognition at Septin Interfaces: The Switches Hold the Key

    Rosa, Higor Vinícius Dias / Leonardo, Diego Antonio / Brognara, Gabriel / Brandão-Neto, José / D'Muniz Pereira, Humberto / Araújo, Ana Paula Ulian / Garratt, Richard Charles

    Journal of molecular biology. 2020 Oct. 02, v. 432, no. 21

    2020  

    Abstract: The assembly of a septin filament requires that homologous monomers must distinguish between one another in establishing appropriate interfaces with their neighbors. To understand this phenomenon at the molecular level, we present the first four crystal ... ...

    Abstract The assembly of a septin filament requires that homologous monomers must distinguish between one another in establishing appropriate interfaces with their neighbors. To understand this phenomenon at the molecular level, we present the first four crystal structures of heterodimeric septin complexes. We describe in detail the two distinct types of G-interface present within the octameric particles, which must polymerize to form filaments. These are formed between SEPT2 and SEPT6 and between SEPT7 and SEPT3, and their description permits an understanding of the structural basis for the selectivity necessary for correct filament assembly. By replacing SEPT6 by SEPT8 or SEPT11, it is possible to rationalize Kinoshita's postulate, which predicts the exchangeability of septins from within a subgroup. Switches I and II, which in classical small GTPases provide a mechanism for nucleotide-dependent conformational change, have been repurposed in septins to play a fundamental role in molecular recognition. Specifically, it is switch I which holds the key to discriminating between the two different G-interfaces. Moreover, residues which are characteristic for a given subgroup play subtle, but pivotal, roles in guaranteeing that the correct interfaces are formed.
    Keywords crystal structure ; guanosinetriphosphatase ; polymerization
    Language English
    Dates of publication 2020-1002
    Size p. 5784-5801.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2020.09.001
    Database NAL-Catalogue (AGRICOLA)

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