Search results for "Protein Structure"

The skeletal proteome of the coral Acropora millepora: the evolution of calcification by co-option and domain shuffling.

2013

14 pages; International audience; In corals, biocalcification is a major function that may be drastically affected by ocean acidification (OA). Scleractinian corals grow by building up aragonitic exoskeletons that provide support and protection for soft tissues. Although this process has been extensively studied, the molecular basis of biocalcification is poorly understood. Notably lacking is a comprehensive catalog of the skeleton-occluded proteins-the skeletal organic matrix proteins (SOMPs) that are thought to regulate the mineral deposition. Using a combination of proteomics and transcriptomics, we report the first survey of such proteins in the staghorn coral Acropora millepora. The or…

2018

ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, al…

Hands On: Using Tryptophan Fluorescence Spectroscopy to Study Protein Structure

2019

Fluorescence spectroscopy is well suited to obtain information about the structure and function of proteins. The major advantage of this spectroscopic technique is the pronounced dependence of the fluorescence emission characteristics of fluorophores on their distinct local environment and the rather inexpensive equipment required. In particular, the use of intrinsic tryptophan fluorescence offers the possibility to study structure and function of proteins without the need to modify the protein. While fluorescence spectroscopy is technically not demanding, a number of factors can artificially alter the results. In this article, we systematically describe the most common applications in fluo…

NMR Investigation of Structures of G-Protein Coupled Receptor Folding Intermediates

2016

Folding of G-protein coupled receptors (GPCRs) according to the two-stage model (Popot, J. L., and Engelman, D. M. (1990) Biochemistry 29, 4031-4037) is postulated to proceed in 2 steps: partitioning of the polypeptide into the membrane followed by diffusion until native contacts are formed. Herein we investigate conformational preferences of fragments of the yeast Ste2p receptor using NMR. Constructs comprising the first, the first two, and the first three transmembrane (TM) segments, as well as a construct comprising TM1-TM2 covalently linked to TM7 were examined. We observed that the isolated TM1 does not form a stable helix nor does it integrate well into the micelle. TM1 is significant…

2,3-Dihydrobenzofuran privileged structures as new bioinspired lead compounds for the design of mPGES-1 inhibitors

2016

International audience; 2,3-Dihydrobenzofurans are proposed as privileged structures and used as chemical platform to design small compound libraries. By combining molecular docking calculations and experimental verification of biochemical interference, we selected some potential inhibitors of microsomal prostaglandin E2 synthase (mPGES)-1. Starting from low affinity natural product 1, by our combined approach we identified the compounds 19 and 20 with biological activity in the low micromolar range. Our data suggest that the 2,3-dihydrobenzofuran derivatives might be suitable bioinspired lead compounds for development of new generation mPGES-1 inhibitors with increased affinity.

A Computational Assay of Estrogen Receptor α Antagonists Reveals the Key Common Structural Traits of Drugs Effectively Fighting Refractory Breast Can…

2017

AbstractSomatic mutations of the Estrogen Receptor α (ERα) occur with an up to 40% incidence in ER sensitive breast cancer (BC) patients undergoing prolonged endocrine treatments. These polymorphisms are implicated in acquired resistance, disease relapse, and increased mortality rates, hence representing a current major clinical challenge. Here, multi-microseconds (12.5 µs) molecular dynamics simulations revealed that recurrent ERα polymorphisms (i. e. L536Q, Y537S, Y537N, D538G) (mERα) are constitutively active in their apo form and that they prompt the selection of an agonist (active)-like conformation even upon antagonists binding. Interestingly, our simulations rationalize, for the firs…

Virus found in a boreal lake links ssDNA and dsDNA viruses.

2017

Viruses have impacted the biosphere in numerous ways since the dawn of life. However, the evolution, genetic, structural, and taxonomic diversity of viruses remain poorly understood, in part because sparse sampling of the virosphere has concentrated mostly on exploring the abundance and diversity of dsDNA viruses. Furthermore, viral genomes are highly diverse, and using only the current sequence-based methods for classifying viruses and studying their phylogeny is complicated. Here we describe a virus, FLiP (Flavobacterium-infecting, lipid-containing phage), with a circular ssDNA genome and an internal lipid membrane enclosed in the icosahedral capsid. The 9,174-nt-long genome showed limite…

The role of Plasma Membrane Calcium ATPases (PMCAs) in neurodegenerative disorders

2017

Selective degeneration of differentiated neurons in the brain is the unifying feature of neurodegenerative disorders such as Parkinson's disease (PD) or Alzheimer's disease (AD). A broad spectrum of evidence indicates that initially subtle, but temporally early calcium dysregulation may be central to the selective neuronal vulnerability observed in these slowly progressing, chronic disorders. Moreover, it has long been evident that excitotoxicity and its major toxic effector mechanism, neuronal calcium overload, play a decisive role in the propagation of secondary neuronal death after acute brain injury from trauma or ischemia. Under physiological conditions, neuronal calcium homeostasis is…

Singular Location and Signaling Profile of Adenosine A2A-Cannabinoid CB1 Receptor Heteromers in the Dorsal Striatum

2018

The dorsal striatum is a key node for many neurobiological processes such as motor activity, cognitive functions, and affective processes. The proper functioning of striatal neurons relies critically on metabotropic receptors. Specifically, the main adenosine and endocannabinoid receptors present in the striatum, ie, adenosine A(2A) receptor (A(2A)R) and cannabinoid CB1 receptor (CB1R), are of pivotal importance in the control of neuronal excitability. Facilitatory and inhibitory functional interactions between striatal A(2A)R and CB1R have been reported, and evidence supports that this cross-talk may rely, at least in part, on the formation of A(2A)R-CB1R heteromeric complexes. However, th…

[1,2]Oxazolo[5,4-e]isoindoles as promising tubulin polymerization inhibitors

2016

Abstract A series of [1,2]Oxazolo [5,4- e ]isoindoles has been synthesized through a versatile and high yielding sequence. All the new structures showed in the 1 HNMR spectra, the typical signal in the 8.34–8.47 ppm attributable to the H-3 of the [1,2]oxazole moiety. Among all derivatives, methoxy benzyl substituents at positions 3 and 4 or/and 5 were very effective in reducing the growth of different tumor cell lines, including diffuse malignant peritoneal mesothelioma (DMPM), an uncommon and rapidly malignancy poorly responsive to available therapeutic options. The most active compound 6j was found to impair tubulin polymerization, cause cell cycle arrest at G2/M phase and induce apoptosi…