Dimerization and Its Role in GMP Formation by Human Guanylate Binding Proteins

Abdullah, Nazish; Balakumari, Meena; Sau, Apurba Kumar

doi:10.1016/j.bpj.2010.07.025

Cited by 23 publications

(43 citation statements)

References 29 publications

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“…We have previously described a dimeric model of hGBP1 that proposes the hydrolysis of GTP as follows [28,29]. After the cleavage of the first phosphoanhydride bond in GTP, there is a competition between the further cleavage of the phosphoanhydride bond in the GDP-bound enzyme dimer to form GMP and dissociation of this dimer into a monomer leading to GDP formation.…”

Section: Scheme 1 Description Of the Full-length Truncated And Chimamentioning

confidence: 99%

“…the α-helix of the intermediate region plays a critical role in dimerization [28]. This protein has also a unique 103 DxEKGD 108 motif near the active site, which is critical for GMP formation [29].…”

Section: Scheme 1 Description Of the Full-length Truncated And Chimamentioning

confidence: 99%

“…The constructs of wt-hGBP1, wt-hGBP2 and hGBP1 307 , and mutants D108A, D103L·D108L, S157A and R48P were prepared as described earlier [28,29]. T75A was obtained as a gift from Dr Peter Cresswell, Yale University.…”

Section: Preparation Of the Chimeric Truncated And Mutant Constructsmentioning

confidence: 99%

“…The crystal structures of full-length hGBP1 and its truncated variant lacking mainly the helical domain were reported with and without the substrate analogue, GppNHp [25][26][27]. Although the protein dimerizes with GppNHp, the structure of the full-length protein was solved with the nucleotide in a monomeric state [28]. hGBP1 consists of two domains, an N-terminal globular domain (catalytic domain) and a C-terminal large helical domain (Scheme 1).…”

Section: Introductionmentioning

confidence: 98%

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Tetrameric assembly of hGBP1 is crucial for both stimulated GMP formation and antiviral activity

Pandita

Rajan

Rahman

et al. 2016

Biochemical Journal

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Interferon-γ inducible human guanylate binding protein-1 (hGBP1) shows a unique characteristic that hydrolyses GTP to a mixture of GDP and GMP through successive cleavages, with GMP being the major product. Like other large GTPases, hGBP1 undergoes oligomerization upon substrate hydrolysis, which is essential for the stimulation of activity. It also exhibits antiviral activity against many viruses including hepatitis C. However, which oligomeric form is responsible for the stimulated activity leading to enhanced GMP formation and its influence on antiviral activity, are not properly understood. Using mutant and truncated proteins, our data indicate that transition-state-induced tetramerization is associated with higher rate of GMP formation. This is supported by chimaeras that are defective in both tetramerization and enhanced GMP formation. Unlike wild-type protein, chimaeras did not show allosteric interactions, indicating that tetramerization and enhanced GMP formation are allosterically coupled. Hence, we propose that after the cleavage of the first phosphoanhydride bond GDP·Pi-bound protein dimers transiently associate to form a tetramer that acts as an allosteric switch for higher rate of GMP formation. Biochemical and biophysical studies reveal that sequential conformational changes and interdomain communications regulate tetramer formation via dimer. Our studies also show that overexpression of the mutants, defective in tetramer formation in Rep2a cells do not inhibit proliferation of hepatitis C virus, indicating critical role of a tetramer in the antiviral activity. Thus, the present study not only highlights the importance of hGBP1 tetramer in stimulated GMP formation, but also demonstrates its role in the antiviral activity against hepatitis C virus.

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Section: Scheme 1 Description Of the Full-length Truncated And Chimamentioning

confidence: 99%

Section: Scheme 1 Description Of the Full-length Truncated And Chimamentioning

confidence: 99%

Section: Preparation Of the Chimeric Truncated And Mutant Constructsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Tetrameric assembly of hGBP1 is crucial for both stimulated GMP formation and antiviral activity

Pandita

Rajan

Rahman

et al. 2016

Biochemical Journal

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“…By formation of an LG domain dimer, an arginine residue is positioned toward the nucleotide pocket leading to enhancement of the catalytic activity (18). Reaction conditions that impair the formation of dimers, e.g., mutations, dilution to low hGBP1 concentrations, or immobilization in a dense packing, result in much slower GTP turnover and in less production of GMP (11,(19)(20)(21).…”

mentioning

confidence: 99%

Nucleotide-dependent farnesyl switch orchestrates polymerization and membrane binding of human guanylate-binding protein 1

Shydlovskyi

Zienert

İnce

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

120

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Dynamin-like proteins (DLPs) mediate various membrane fusion and fission processes within the cell, which often require the polymerization of DLPs. An IFN-inducible family of DLPs, the guanylate-binding proteins (GBPs), is involved in antimicrobial and antiviral responses within the cell. Human guanylate-binding protein 1 (hGBP1), the founding member of GBPs, is also engaged in the regulation of cell adhesion and migration. Here, we show how the GTPase cycle of farnesylated hGBP1 (hGBP1F) regulates its self-assembly and membrane interaction. Using vesicles of various sizes as a lipid bilayer model, we show GTP-dependent membrane binding of hGBP1F. In addition, we demonstrate nucleotide-dependent tethering ability of hGBP1F. Furthermore, we report nucleotide-dependent polymerization of hGBP1F, which competes with membrane binding of the protein. Our results show that hGBP1F acts as a nucleotide-controlled molecular switch by modulating the accessibility of its farnesyl moiety, which does not require any supportive proteins.

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Integrative modeling of guanylate binding protein dimers

Schumann,

Loschwitz,

Reiners

et al. 2023

Protein Science

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Guanylate‐binding proteins (GBPs) are essential interferon‐γ‐activated large GTPases that play a crucial role in host defense against intracellular bacteria and parasites. While their protective functions rely on protein polymerization, our understanding of the structural intricacies of these multimerized states remains limited. To bridge this knowledge gap, we present dimer models for human GBP1 (hGBP1) and murine GBP2 and 7 (mGBP2 and mGBP7) using an integrative approach, incorporating the crystal structure of hGBP1's GTPase domain dimer, crosslinking mass spectrometry (XL‐MS), small‐angle X‐ray scattering (SAXS), protein‐protein docking, and molecular dynamics (MD) simulations. Our investigation begins by comparing the protein dynamics of hGBP1, mGBP2, and mGBP7. We observe that the M/E domain in all three proteins exhibits significant mobility and hinge motion, with mGBP7 displaying a slightly less pronounced motion but greater flexibility in its GTPase domain. These dynamic distinctions can be attributed to variations in the sequences of mGBP7 and hGBP1/mGBP2, resulting in different dimerization modes. Unlike hGBP1 and its close ortholog mGBP2, which exclusively dimerize through their GTPase domains, we find that mGBP7 exhibits three equally probable alternative dimer structures. The GTPase domain of mGBP7 is only partially involved in its dimerization, primarily due to an accumulation of negative charge, allowing mGBP7 to dimerize independently of GTP. Instead, mGBP7 exhibits a strong tendency to dimerize in an antiparallel arrangement across its stalks. The results of this work go beyond the sequence‐structure‐function relationship, as the sequence differences in mGBP7 and mGBP2/hGBP1 do not lead to different structures, but to different protein dynamics and dimerization. The distinct GBP dimer structures are expected to encode specific functions crucial for disrupting pathogen membranes.This article is protected by copyright. All rights reserved.

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Dimerization and Its Role in GMP Formation by Human Guanylate Binding Proteins

Cited by 23 publications

References 29 publications

Tetrameric assembly of hGBP1 is crucial for both stimulated GMP formation and antiviral activity

Tetrameric assembly of hGBP1 is crucial for both stimulated GMP formation and antiviral activity

Nucleotide-dependent farnesyl switch orchestrates polymerization and membrane binding of human guanylate-binding protein 1

Integrative modeling of guanylate binding protein dimers

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