Functional and Biochemical Characterization of Alvinella pompejana Cys-Loop Receptor Homologues

Wijckmans, Eveline; Nys, Mieke; Debaveye, Sarah; Brams, Marijke; Pardon, Els; Willegems, Katrien; Bertrand, Daniel; Steyaert, Jan; Efremov, Rouslan G.; Ulens, Chris

doi:10.1371/journal.pone.0151183

Cited by 5 publications

(20 citation statements)

References 59 publications

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“…The naming convention was subsequently adopted such that by definition the α subunits are those with the vicinal SS. Indeed it has remained true that all functional pentamers in nAChR, and in many similar receptors across a wide variety of organisms, contain at least one α subunit which forms the “principal” face of the intersubunit binding site 40-42 , opposite the “complementary” binding face of the adjacent subunit. [Note: the vicinal SS is in “Loop C”, not in the 13-residue “Cys loop” that is also an important feature of the principal binding face.…”

Section: Resultsmentioning

confidence: 99%

Broad Analysis of Vicinal Disulfides: Occurrences, Conformations with Cis or with Trans Peptides, and Functional Roles Including Sugar Binding

Richardson

Videau

Williams

et al. 2017

Journal of Molecular Biology

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Vicinal disulfides between sequence-adjacent cysteine residues are very rare and rather startling structural features which play a variety of functional roles. Typically discussed as an isolated curiosity, they have never received a general treatment covering both cis and trans forms. Enabled by the growing database of high-resolution structures, required deposition of diffraction data, and improved methods for discriminating reliable from dubious cases, we here identify and describe distinct protein families with reliably genuine examples of cis or trans vicinal disulfides and discuss their conformations, conservation, and functions. No cis-trans interconversions and only one case of catalytic redox function are seen. Some vicinal disulfides are essential to large, functionally coupled motions, whereas most form the centers of tightly packed internal regions. Their most widespread biological role is providing a rigid hydrophobic contact surface under the undecorated side of a sugar or multi-ring ligand, contributing an important aspect of binding specificity.

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Section: Resultsmentioning

confidence: 99%

Broad Analysis of Vicinal Disulfides: Occurrences, Conformations with Cis or with Trans Peptides, and Functional Roles Including Sugar Binding

Richardson

Videau

Williams

et al. 2017

Journal of Molecular Biology

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“…We further refer to this structure as Alpo4 CHAPS . CHAPS was present in the purified Alpo4 at a concentration of 0.007% (110 μM) because of its thermostabilizing effect on Alpo4 26 . At 110 μM, the CHAPS concentration is 70-fold lower than the critical micellar concentration (CMC) of the detergent, suggesting a specific interaction with Alpo4 beyond modulating properties of the detergent belt and therefore is consistent with CHAPS binding to the orthosteric site 31 .…”

Section: Resultsmentioning

confidence: 99%

“…The high biochemical stability and preliminary characterization using negative stain electron microscopy suggested that Alpo4 was a promising target for structural studies 27 . However, despite exhaustive screening in different expression systems in combination with a compound library, including acetylcholine and serotonin, we could not identify the agonist/neurotransmitter for Alpo4, thereby limiting functional studies 26 . Because of its biochemical stability and unique position between nAChRs and 5-HT 3 receptors we characterized the structure of Alpo4 using single-particle electron cryogenic microscopy (cryo-EM).…”

Section: Introductionmentioning

confidence: 98%

“…We have previously biochemically characterized seven invertebrate Cys-loop receptors, Alpo1-7, identified in the proteome of Alvinella pompejana , an annelid worm that inhabits the surroundings of hydrothermal vents and is the most extreme thermophilic invertebrate currently known 24,25 . Among seven Alpo receptors, we identified two nAChR-like receptors (Alpo1 and Alpo4) and one Gly-like receptor (Alpo6), which were expressed and purified in amounts suitable for structural studies 26 . Alpo4 has 27-29% sequence identity with α-subunits of nAChRs and 25% with 5-HT 3 receptors.…”

Section: Introductionmentioning

confidence: 99%

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Sterol derivative binding to the orthosteric site causes conformational changes in an invertebrate Cys-loop receptor

Gieter

Wijckmans

Pasini

et al. 2023

Preprint

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Cys-loop receptors or pentameric ligand-gated ion channels are mediators of electrochemical signaling throughout the animal kingdom. Because of their critical function in neurotransmission and high potential as drug targets, Cys-loop receptors from humans and closely related organisms have been thoroughly investigated, whereas molecular mechanisms of neurotransmission in invertebrates are less understood. When compared with vertebrates, the invertebrate genomes underwent a drastic expansion in the number of the nACh-like genes associated with receptors of unknown function. Understanding this diversity contributes to better insight into the evolution and possible functional divergence of these receptors. In this work, we studied orphan receptor Alpo4 from an extreme thermophile worm Alvinella pompejana. Sequence analysis points towards its remote relation to characterized nACh receptors. We solved the first cryo-EM structure of a lophotrochozoan nACh-like receptor in which a CHAPS molecule is tightly bound to the orthosteric site. We show that the binding of CHAPS leads to extending of the loop C at the orthosteric site and a clockwise quaternary twist between extracellular and transmembrane domains. Both the ligand binding site and the channel pore reveal unique features. These include a conserved Trp residue in loop B of the ligand binding site which is flipped into an apparent self-liganded state in the apo structure. The ion pore of Alpo4 is tightly constricted by a ring of methionines near the extracellular entryway of the channel pore. Our data provide a structural basis for a functional understanding of Alpo4 and hints towards new strategies for designing specific channel modulators.

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“…As the mammalian ligand appeared later in evolution, we could draw up a scenario in which an ancestral ligand, phylogenetically unrelated to the human one, but very similar to it in its binding properties, was replaced in some branches, including the mammals [32]. Such scenarios have already been described [33,34]. Indeed, thanks to these examples, we understand that for these partners, the receptor in fact did not appeare before its first ligand.…”

Section: Plos Onementioning

confidence: 94%

The membrane receptors that appeared before their ligand: The different proposed scenarios

Grandchamp

Monget

2020

PLoS ONE

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The interactions between membrane receptors and their endogenous ligands are key interactions in organisms. Recently, we have shown that a high number of genes encoding human receptors appeared at the same moment as their ligand in the animal tree of life. However, a set of receptors appeared before their present ligand. Different scenarios have been proposed to explain how a receptor can be conserved if its ligand is not yet appeared. However, these scenarios have been proposed individually and have never been studied in a global way. In this study, we investigated 30 mammalian pairs of ligand/receptor for which the first ligand appeared after its receptor in the tree of life, by using common indexes of selection, and proposed different scenarios explaining the earlier appearance of a receptor relative to its ligand. Based on 3D structural studies, our indexes allowed us to classify the evolution of these partners into different scenarios: 1) a scenario where the binding interface of the receptor is already present and under purifying selection before the appearance of the ligand; 2) a scenario where the binding interface seems to have appeared progressively, and 3) a scenario where the binding site seems to have been reshuffled since its appearance. As some scenarios were confirmed by the literature, we concluded that simple indexes can give a good highlight of the evolutive history of two partners that did not appear at the same time. Based on these scenarios, we also hypothesize that the replacement of a ligand by another is a frequent phenomenon during evolution.

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Functional and Biochemical Characterization of Alvinella pompejana Cys-Loop Receptor Homologues

Cited by 5 publications

References 59 publications

Broad Analysis of Vicinal Disulfides: Occurrences, Conformations with Cis or with Trans Peptides, and Functional Roles Including Sugar Binding

Broad Analysis of Vicinal Disulfides: Occurrences, Conformations with Cis or with Trans Peptides, and Functional Roles Including Sugar Binding

Sterol derivative binding to the orthosteric site causes conformational changes in an invertebrate Cys-loop receptor

The membrane receptors that appeared before their ligand: The different proposed scenarios

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