scholarly journals Crystal structure of the glutamate receptor GluA1 N-terminal domain

2011 ◽  
Vol 438 (2) ◽  
pp. 255-263 ◽  
Author(s):  
Guorui Yao ◽  
Yinong Zong ◽  
Shenyan Gu ◽  
Jie Zhou ◽  
Huaxi Xu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Protein Interactions ◽  
Ampa Receptors ◽  
Neurological Diseases ◽  
Protein Protein Interactions ◽  
Terminal Domain ◽  
The Central Nervous System ◽  
In Trans ◽  
Excitatory Neurotransmission ◽  
Active Channels

The AMPA (α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) subfamily of iGluRs (ionotropic glutamate receptors) is essential for fast excitatory neurotransmission in the central nervous system. The malfunction of AMPARs (AMPA receptors) has been implicated in many neurological diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. The active channels of AMPARs and other iGluR subfamilies are tetramers formed exclusively by assembly of subunits within the same subfamily. It has been proposed that the assembly process is controlled mainly by the extracellular ATD (N-terminal domain) of iGluR. In addition, ATD has also been implicated in synaptogenesis, iGluR trafficking and trans-synaptic signalling, through unknown mechanisms. We report in the present study a 2.5 Å (1 Å=0.1 nm) resolution crystal structure of the ATD of GluA1. Comparative analyses of the structure of GluA1-ATD and other subunits sheds light on our understanding of how ATD drives subfamily-specific assembly of AMPARs. In addition, analysis of the crystal lattice of GluA1-ATD suggests a novel mechanism by which the ATD might participate in inter-tetramer AMPAR clustering, as well as in trans-synaptic protein–protein interactions.

scholarly journals Crystal structure of XCC3289 from Xanthomonas campestris: homology with the N-terminal substrate-binding domain of Lon peptidase

2020 ◽  
Vol 76 (10) ◽  
pp. 488-494
Author(s):  
Rahul Singh ◽  
Sonali Deshmukh ◽  
Ashwani Kumar ◽  
Venuka Durani Goyal ◽  
Ravindra D. Makde
Keyword(s):  
Crystal Structure ◽  
Protein Interactions ◽  
Xanthomonas Campestris ◽  
Protein Quality ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Homologous Proteins ◽  
Terminal Domain ◽  
Α Helix ◽  
Terminal Domains

LonA peptidase is a major component of the protein quality-control mechanism in both prokaryotes and the organelles of eukaryotes. Proteins homologous to the N-terminal domain of LonA peptidase, but lacking its other domains, are conserved in several phyla of prokaryotes, including the Xanthomonadales order. However, the function of these homologous proteins (LonNTD-like proteins) is not known. Here, the crystal structure of the LonNTD-like protein from Xanthomonas campestris (XCC3289; UniProt Q8P5P7) is reported at 2.8 Å resolution. The structure was solved by molecular replacement and contains one polypeptide in the asymmetric unit. The structure was refined to an R free of 29%. The structure of XCC3289 consists of two domains joined by a long loop. The N-terminal domain (residues 1–112) consists of an α-helix surrounded by β-sheets, whereas the C-terminal domain (residues 123–193) is an α-helical bundle. The fold and spatial orientation of the two domains closely resembles those of the N-terminal domains of the LonA peptidases from Escherichia coli and Mycobacterium avium. The structure is also similar to that of cereblon, a substrate-recognizing component of the E3 ubiquitin ligase complex. The N-terminal domains of both LonA and cereblon are known to be involved in specific protein–protein interactions. This structural analysis suggests that XCC3289 and other LonNTD-like proteins might also be capable of such protein–protein interactions.

Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

scholarly journals Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

Regulative interactions of the osmosensing C-terminal domain in the trimeric glycine betaine transporter BetP from Corynebacterium glutamicum

2009 ◽  
Vol 390 (8) ◽  
Author(s):  
Reinhard Krämer ◽  
Christine Ziegler
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Protein Interactions ◽  
Regulation Mechanism ◽  
Protein Protein Interactions ◽  
Molecular Switching ◽  
X Ray ◽  
X Ray Crystallography ◽  
Terminal Domain ◽  
Domain Reorientation

Abstract Activation of the osmoregulated trimeric betaine transporter BetP from Corynebacterium glutamicum was shown to depend mainly on the correct folding and integrity of its 55 amino acid long, partly α-helical C-terminal domain. Reorientation of the three C-terminal domains in the BetP trimer indicates different lipid-protein and protein-protein interactions of the C-terminal domain during osmoregulation. A regulation mechanism is suggested where this domain switches the transporter from the inactive to the active state. Interpretation of recently obtained electron and X-ray crystallography data of BetP led to a structure-function based model of C-terminal molecular switching involved in osmoregulation.

scholarly journals The Disordered Cellular Multi-Tasker WIP and Its Protein–Protein Interactions: A Structural View

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1084 ◽  
Author(s):  
Chana G. Sokolik ◽  
Nasrin Qassem ◽  
Jordan H. Chill
Keyword(s):  
Protein Interactions ◽  
Cell Biology ◽  
Intrinsically Disordered Proteins ◽  
Disordered Proteins ◽  
Actin Binding ◽  
Structural Description ◽  
Protein Protein Interactions ◽  
Intrinsically Disordered ◽  
Terminal Domain ◽  
Binding Partners

WASp-interacting protein (WIP), a regulator of actin cytoskeleton assembly and remodeling, is a cellular multi-tasker and a key member of a network of protein–protein interactions, with significant impact on health and disease. Here, we attempt to complement the well-established understanding of WIP function from cell biology studies, summarized in several reviews, with a structural description of WIP interactions, highlighting works that present a molecular view of WIP’s protein–protein interactions. This provides a deeper understanding of the mechanisms by which WIP mediates its biological functions. The fully disordered WIP also serves as an intriguing example of how intrinsically disordered proteins (IDPs) exert their function. WIP consists of consecutive small functional domains and motifs that interact with a host of cellular partners, with a striking preponderance of proline-rich motif capable of interactions with several well-recognized binding partners; indeed, over 30% of the WIP primary structure are proline residues. We focus on the binding motifs and binding interfaces of three important WIP segments, the actin-binding N-terminal domain, the central domain that binds SH3 domains of various interaction partners, and the WASp-binding C-terminal domain. Beyond the obvious importance of a more fundamental understanding of the biology of this central cellular player, this approach carries an immediate and highly beneficial effect on drug-design efforts targeting WIP and its binding partners. These factors make the value of such structural studies, challenging as they are, readily apparent.

Glycoprotein Ibalpha Inhibitor Complex Crystal Structure at High Resolution.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 774-774
Author(s):  
P.A Mcewan ◽  
Robert K Andrews ◽  
Jonas Emsley
Keyword(s):  
Crystal Structure ◽  
Shear Stress ◽  
Protein Interactions ◽  
Platelet Adhesion ◽  
Peptide Sequence ◽  
Leucine Rich Repeat ◽  
Protein Protein Interactions ◽  
Leucine Rich Repeats ◽  
Von Willebrand ◽  
Complex Crystal

Abstract Abstract 774 Introduction: The platelet Glycoprotein Ib/V/IX (GpIb/V/IX) complex is considered a major target for anticoagulant therapy. The primary function of the receptor is to mediate platelet adhesion to von Willebrand factor (VWF) bound to damaged sub-endothelium. This represents the first critical step for platelet adhesion under conditions of high fluid shear stress. GpIb/V/IX is implicated in a number of thrombotic pathological processes such as stroke or myocardial infarction and the bleeding disorders Bernard-Soulier syndrome, platelet type von Willebrand disease (Pt-VWD) and thrombotic thrombocytopenic purpura. We have successfully determined the structure of the GpIbalpha N-terminal domain in complex with a potent (sub nM) 11meric peptide inhibitor (OS1) of the interaction with VWF. Methods: We have determined the crystal structure to 1.8Å resolution using molecular replacement. Results. The peptide sequence CTERMALHNLC was readily identifiable bound to GpIbalpha between the extended regulatory (R) loop and the concave surface of the leucine rich repeats. The peptide adopts one and a half turns of an alpha-helix and contacts three subsites (S1, S2 and S3). S1 and S2 reside within the leucine rich repeats and S3 has a unique feature as this subsite involves contact with the regulatory R-loop stabilizing it in a well defined conformation with helical character. This loop alters conformation between an extended beta-hairpin in the VWF-A1 bound structure and a more compact largely disordered structure in the unliganded structure. In this regard, the Pt-VWD mutations of GpIbalpha, G233V and M239V, which reside in the R-loop act by inducing a beta-conformation and thus result in a high affinity form of the receptor. Conclusions: These studies provide a strategy for targeting the GpIbalpha-VWF interaction using small molecules or alpha-helical peptides exploiting the GpIbalpha subsites described here and acting allosterically to stabilise a low affinity conformation of the receptor with an alpha helical R-loop. Ligand mimetic peptide complex crystal structures for the platelet receptors integrin aIIbb3 with RGD, and alpha2beta1 with a collagen peptide have been described and the former are currently in therapeutic use for treatment of thromboemboletic disorders. Targeting the GpIbalpha-VWF interaction may provide anti-thrombotic drugs which affect platelet adhesion under high shear stress without compromising normal processes of platelet adhesion and aggregation which may be required for normal hemostasis to function. Targeting protein-protein interactions is considered one of the great contemporary challenges in drug discovery. The understanding of how the S1S2S3 subsites provide very effective inhibition of a large protein-protein interaction has wide applicability. LRR proteins are an extended family mediating protein-protein interactions involved in a variety of disease processes such as sepsis, asthma, immunodeficiencies, atherosclerosis, alzheimers (leucine rich repeat kinase) and leukaemia (leucine rich repeat phosphatase). The structural fit of the helical curvature of the peptide with the arc of the leucine rich repeats may provide a basis for further development of alpha-helical peptide mimetics targeting other members of the LRR family which utilize the concave face. Disclosures: No relevant conflicts of interest to declare.

scholarly journals GluR2 protein-protein interactions and the regulation of AMPA receptors during synaptic plasticity

2003 ◽  
Vol 358 (1432) ◽  
pp. 715-720 ◽  
Author(s):  
Fabrice Duprat ◽  
Michael Daw ◽  
Wonil Lim ◽  
Graham Collingridge ◽  
John Isaac
Keyword(s):  
Synaptic Plasticity ◽  
Ampa Receptor ◽  
Protein Interactions ◽  
Ampa Receptors ◽  
Long Term Potentiation ◽  
Synaptic Proteins ◽  
Mammalian Brain ◽  
Protein Protein Interactions ◽  
Term Potentiation

AMPA-type glutamate receptors mediate most fast excitatory synaptic transmissions in the mammalian brain. They are critically involved in the expression of long-term potentiation and long-term depression, forms of synaptic plasticity that are thought to underlie learning and memory. A number of synaptic proteins have been identified that interact with the intracellular C-termini of AMPA receptor subunits. Here, we review recent studies and present new experimental data on the roles of these interacting proteins in regulating the AMPA receptor function during basal synaptic transmission and plasticity.

scholarly journals Thyroid stimulating autoantibody M22 mimics TSH binding to the TSH receptor leucine rich domain: a comparative structural study of protein–protein interactions

2009 ◽  
Vol 42 (5) ◽  
pp. 381-395 ◽  
Author(s):  
R Núñez Miguel ◽  
J Sanders ◽  
D Y Chirgadze ◽  
J Furmaniak ◽  
B Rees Smith
Keyword(s):  
Crystal Structure ◽  
Protein Interactions ◽  
Hydrophobic Interactions ◽  
Human Monoclonal Antibody ◽  
Tsh Receptor ◽  
Salt Bridges ◽  
Protein Protein Interactions ◽  
Rich Domain ◽  
Candidate Target ◽  
Comparative Model

The TSH receptor (TSHR) ligands M22 (a thyroid stimulating human monoclonal antibody) and TSH, bind to the concave surface of the leucine rich repeats domain (LRD) of the TSHR and here, we show that M22 mimics closely the binding of TSH. We compared interactions produced by M22 with the TSHR in the M22–TSHR crystal structure (2.55 Å resolution) and produced by TSH with the TSHR in a TSH–TSHR comparative model. The crystal structure of the TSHR and a comparative model of TSH based on the crystal structure of FSH were used as components to build the TSH–TSHR model. This model was built based on the FSH–FSH receptor structure (2.9 Å) and then the structure of the TSHR in the model was replaced by the TSHR crystal structure. The analysis shows that M22 light chain mimics the TSHβ chain in its interaction with TSHR LRD, while M22 heavy chain mimics the interactions of the TSHα chain. The M22–TSHR complex contains a greater number of hydrogen bonds and salt bridges and fewer hydrophobic interactions than the TSH–TSHR complex, consistent with a higher M22 binding affinity. Furthermore, the surface area formed by TSHR residues N208, Q235, R255, and N256 has been identified as a candidate target region for small molecules which might selectively block binding of autoantibodies to the TSHR.

scholarly journals The Crystal Structure of Klebsiella pneumoniae FeoA Reveals a Site For Protein-Protein Interactions

2019 ◽  
Author(s):  
Richard O. Linkous ◽  
Alexandrea E. Sestok ◽  
Aaron T. Smith
Keyword(s):  
Crystal Structure ◽  
Klebsiella Pneumoniae ◽  
Protein Interactions ◽  
Pathogenic Bacteria ◽  
Protein Protein Interactions ◽  
Anaerobic Conditions ◽  
Small Peptide ◽  
Host Environment ◽  
Partner Protein ◽  
A Site

ABSTRACTIn order to establish infection, pathogenic bacteria must obtain essential nutrients such as iron. Under acidic and/or anaerobic conditions, most bacteria utilize the Feo system in order to acquire ferrous iron (Fe2+) from their host environment. The mechanism of this process, including its regulation, remains poorly understood. In this work, we have determined the crystal structure of FeoA from the nosocomial agent Klebsiella pneumoniae (KpFeoA). Our structure reveals an SH3-like domain that mediates interactions between neighboring polypeptides via intercalations into a Leu zipper motif. Using docking of a small peptide corresponding to a postulated FeoB partner binding site, we demonstrate the KpFeoA can assume both ‘open’ and ‘closed’ conformations, controlled by peptide binding. We propose a model in which a ‘C-shaped’ clamp along the FeoA surface mediates interactions with its partner protein, FeoB. These findings are the first to demonstrate atomic-level details of FeoA-based protein-protein interactions, which could be exploited for future antibiotic developments.

Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

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