Scott C Blanchard

Scott C Blanchard
St. Jude Children's Research Hospital · Department of Structural Biology

PhD, Biophysics
https://orcid.org/my-orcid?orcid=0000-0003-2717-9365

About

228
Publications
35,153
Reads
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12,170
Citations
Citations since 2016
126 Research Items
7682 Citations
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201620172018201920202021202202004006008001,0001,200
201620172018201920202021202202004006008001,0001,200
Introduction
Research in the Blanchard laboratory focuses on examining structure-function relationships in macromolecular assemblies, including bacterial and human ribosomes as well as integral membrane proteins, using a variety of genetic, biochemical, and spectroscopic approaches. A principal goal of these investigations is to reveal regulatory paradigms that explain how cellular factors and small-molecules affect the function of essential molecular machines. We seek to leverage these information to improve the efficacy clinical interventions for the betterment of patient care.
Additional affiliations
June 2019 - present
St. Jude Children's Research Hospital
Position
  • Chair
June 2019 - present
Weill Cornell Medical College
Position
  • Professor
June 2013 - May 2019
Weill Cornell Medical College
Position
  • Professor
Education
July 1996 - June 2004
Stanford University
Field of study
  • Biophysics, Structural Biology, Applied Physics

Publications

Publications (228)
Article
Full-text available
Rapid and accurate mRNA translation requires efficient codon-dependent delivery of the correct aminoacyl-tRNA (aa-tRNA) to the ribosomal A site. In mammals, this fidelity-determining reaction is facilitated by the GTPase elongation factor-1 alpha (eEF1A), which escorts aa-tRNA as an eEF1A(GTP)-aa-tRNA ternary complex into the ribosome. The structur...
Article
In this perspective, we highlight the recent progress in utilizing Baird aromatic species to improve fluorophore performance in microscopy and imaging applications. We specifically focus on the origins of the use of Baird aromaticity in fluorescence applications, the development of “self‐healing” fluorophores leveraging cyclooctatetraene’ Baird aro...
Article
Full-text available
Ternatin-family cyclic peptides inhibit protein synthesis by targeting the eukaryotic elongation factor-1α. A potentially related cytotoxic natural product (‘A3’) was isolated from Aspergillus, but only 4 of its 11 stereocentres could be assigned. Here, we synthesized SR-A3 and SS-A3—two out of 128 possible A3 epimers—and discovered that synthetic...
Preprint
Full-text available
Rapid and accurate mRNA translation requires efficient codon-dependent delivery of the correct aminoacyl-tRNA (aa-tRNA) to the ribosomal A site. In mammals, this fidelity-determining reaction is facilitated by the GTPase elongation factor-1 alpha (eEF1A), which escorts aa-tRNA as an eEF1A(GTP)-aa-tRNA ternary complex into the ribosome. Two structur...
Article
Translocation of messenger RNA (mRNA) and transfer RNA (tRNA) substrates through the ribosome during protein synthesis, an exemplar of directional molecular movement in biology, entails a complex interplay of conformational, compositional, and chemical changes. The molecular determinants of early translocation steps have been investigated rigorousl...
Article
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Significance The increase in multidrug-resistant bacteria highlights the urgent need for compounds with novel target sites that can be developed as antibiotics. The argyrins represent a family of naturally produced octapeptides that display promising activity against Pseudomonas aeruginosa by inhibiting protein synthesis. Our structural and kinetic...
Article
Full-text available
β-arrestins bind G protein-coupled receptors to terminate G protein signaling and to facilitate other downstream signaling pathways. Using single-molecule fluorescence resonance energy transfer imaging, we show that β-arrestin is strongly autoinhibited in its basal state. Its engagement with a phosphopeptide mimicking phosphorylated receptor tail e...
Article
Full-text available
Significance Structural snapshots of membrane transporters show that they cycle through several conformational states to bring substrates across the membrane. The rates of these molecular motions determine the activity of the transporters. In this work, we directly compare real-time single-molecule measurements of conformational changes and substra...
Article
Full-text available
Survival in high-risk pediatric neuroblastoma has remained around 50% for the last 20 years, with immunotherapies and targeted therapies having had minimal impact. Here, we identify the small molecule CX-5461 as selectively cytotoxic to high-risk neuroblastoma and synergistic with low picomolar concentrations of topoisomerase I inhibitors in improv...
Article
Full-text available
Peptide-chain elongation during protein synthesis entails sequential aminoacyl-tRNA selection and translocation reactions that proceed rapidly (2–20 per second) and with a low error rate (around 10⁻³ to 10⁻⁵ at each step) over thousands of cycles¹. The cadence and fidelity of ribosome transit through mRNA templates in discrete codon increments is a...
Article
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Secondary active transporters reside in cell membranes transporting polar solutes like amino acids against steep concentration gradients, using electrochemical gradients of ions as energy sources. Commonly, ensemble-based measurements of radiolabeled substrate uptakes or transport currents inform on kinetic parameters of transporters. Here we descr...
Article
Full-text available
Class C G protein-coupled receptors (GPCRs) are known to form stable homodimers or heterodimers critical for function, but the oligomeric status of class A and B receptors, which constitute >90% of all GPCRs, remains hotly debated. Single-molecule fluorescence resonance energy transfer (smFRET) is a powerful approach with the potential to reveal va...
Article
Full-text available
Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that emplo...
Preprint
Survival in high-risk pediatric neuroblastoma has remained around 50% for the last 20 years, with immunotherapies and targeted therapies having had minimal impact. Here, we identify the small molecule CX-5461 as selectively cytotoxic to high-risk neuroblastoma and synergistic with low picomolar concentrations of topoisomerase I inhibitors improving...
Chapter
Messenger RNA (mRNA)-directed protein synthesis is carried out by the ribosome, a macromolecular assembly composed of over 70 distinct gene products. During the elongation phase of this multistep, regulated process, the ribosome “reads” the codon sequence of mRNA to synthesize specific polypeptides. This entails repetitive cycles of aminoacyl-trans...
Article
Full-text available
Membrane transporters mediate cellular uptake of nutrients, signaling molecules, and drugs. Their overall mechanisms are often well understood, but the structural features setting their rates are mostly unknown. Earlier single-molecule fluorescence imaging of the archaeal model glutamate transporter homologue GltPh from Pyrococcus horikoshii sugges...
Article
Full-text available
Molecular Dynamics (MD) simulations seek to provide atomic-level insights into conformationally dynamic biological systems at experimentally relevant time resolutions, such as those afforded by single-molecule fluorescence measurements. However, limitations in the time scales of MD simulations and the time resolution of single-molecule measurements...
Article
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) mediates viral entry into cells and is critical for vaccine development against coronavirus disease 2019 (COVID-19). Structural studies have revealed distinct conformations of S, but real-time information that connects these structures is lacking. Here we apply single-molecu...
Article
SARS-CoV-2 spike (S) mediates entry into cells and is critical for vaccine development against COVID-19. S is synthesized as a precursor, processed into S1 and S2 by furin proteases, and activated for fusion when human angiotensin-converting enzyme 2 (hACE2) engages the receptor-binding domain (RBD) and when the N-terminus of S2 is proteolytically...
Article
Full-text available
Significance Fluorescence imaging, a central pillar of medical and fundamental research, is hampered by stochastic blinking, limited photon budgets, and phototoxicities of organic fluorophores. Here, we use quantum chemical calculations and targeted synthetic strategies to tune the Baird aromatic triplet-state energy of cyclooctatetraene to enhance...
Article
Full-text available
The HIV-1 envelope glycoprotein (Env) trimer, composed of gp120 and gp41 subunits, mediates viral entry into cells. Recombinant Env trimers have been studied structurally, but characterization of Env embedded in intact virus membranes has been limited to low resolution. Here, we deploy cryo-electron tomography and subtomogram averaging to determine...
Article
The HIV-1 envelope glycoprotein (Env) opens in response to receptor CD4 binding from a pretriggered (state 1) conformation through a necessary intermediate to the three-CD4-bound conformation. The application of smFRET to test the conformational state of existing Env constructs and ligand complexes used for high-resolution structures recently revea...
Preprint
Full-text available
Single-molecule F\"{o}rster resonance energy transfer (smFRET) has become a mainstream technique for probing biomolecular structural dynamics. The rapid and wide adoption of the technique by an ever-increasing number of groups has generated many improvements and variations in the technique itself, in methods for sample preparation and characterizat...
Article
Full-text available
Single-molecule Förster resonance energy transfer (smFRET) has become a mainstream technique for probing biomolecular structural dynamics. The rapid and wide adoption of the technique by an ever-increasing number of groups has generated many improvements and variations in the technique itself, in methods for sample preparation and characterization,...
Article
Full-text available
Kinetic properties of membrane transporters are typically poorly defined because high-resolution functional assays analogous to single-channel recordings are lacking. Here, we measure single-molecule transport kinetics of a glutamate transporter homolog from Pyrococcus horikoshii , Glt Ph , using fluorescently labeled periplasmic amino acid binding...
Preprint
Full-text available
Membrane transporters mediate cellular uptake of nutrients, signaling molecules and drugs. Their overall mechanisms are often well understood, but the structural features setting their rates are mostly unknown. Earlier single-molecule fluorescence imaging of a model glutamate transporter homologue suggested that the slow conformational transition f...
Article
The envelope glycoprotein (Env) spike on the surface of human immunodeficiency virus type 1 (HIV-1) mediates the entry of the virus into host cells and is also the target for antibodies. During virus entry, Env needs to change shape. Env flexibility also contributes to the ability of HIV-1 to evade the host immune response; many shapes of Env raise...
Article
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An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
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Neurotransmitter:sodium symporters (NSS) are conserved from bacteria to man and serve as targets for drugs, including antidepressants and psychostimulants. Here we report the X-ray structure of the prokaryotic NSS member, LeuT, in a Na+/substrate-bound, inward-facing occluded conformation. To obtain this structure, we were guided by findings from s...
Article
Full-text available
Significance Elongation factor Tu (EF-Tu) facilitates rapid and accurate selection of aminoacyl-tRNA (aa-tRNA) by the bacterial ribosome during protein synthesis. We show that EF-Tu dissociates from the ribosome as aa-tRNA navigates the accommodation corridor en route to peptide bond formation. We find that EF-Tu’s release from the ribosome during...
Article
Full-text available
Selection of correct aminoacyl(aa)-tRNA at the ribosomal A site is fundamental to maintaining translational fidelity. Aa-tRNA selection is a multistep process facilitated by the GTPase elongation factor (EF)-Tu. EF-Tu delivers aa-tRNA to the ribosomal A site and participates in tRNA selection. The structural mechanism of how EF-Tu is involved in pr...
Article
Full-text available
The trimeric HIV-1 Envelope protein (Env) mediates viral-host cell fusion via a network of conformational transitions, with allosteric elements in each protomer orchestrating host receptor-induced exposure of the co-receptor binding site and fusion elements. To understand the molecular details of this allostery, here, we introduce Env mutations aim...
Preprint
Full-text available
The trimeric HIV-1 Envelope protein (Env) mediates viral-host cell fusion via a network of conformational transitions, with allosteric elements in each protomer orchestrating host receptor-induced exposure of the co-receptor binding site and fusion elements. To understand the molecular details of this allostery, we introduced Env mutations aimed to...
Article
Full-text available
Cytoplasmic dynein is an ATP-driven motor that transports intracellular cargos along microtubules. Dynein adopts an inactive conformation when not attached to a cargo, and motility is activated when dynein assembles with dynactin and a cargo adaptor. It was unclear how active dynein–dynactin complexes step along microtubules and transport cargos un...
Article
Full-text available
Secondary active transporters, which are vital for a multitude of physiological processes, use the energy of electrochemical ion gradients to power substrate transport across cell membranes1,2. Efforts to investigate their mechanisms of action have been hampered by their slow transport rates and the inherent limitations of ensemble methods. Here we...
Article
Full-text available
Small nucleolar RNAs (snoRNAs) are a diverse group of non-coding RNAs that direct chemical modifications at specific residues on other RNA molecules, primarily on ribosomal RNA (rRNA). SnoRNAs are altered in several cancers; however, their role in cell homeostasis as well as in cellular transformation remains poorly explored. Here, we show that spe...
Article
Full-text available
The article Implications of sequence variation on the evolution of rRNA, written by Matthew M. Parks, Chad M. Kurylo, Jake E. Batchelder, C. Theresa Vincent and Scott C. Blanchard, was originally published electronically on the publisher’s internet portal (currently SpringerLink).
Article
Full-text available
Significance The combination of molecular dynamics simulation, single-molecule imaging, and functional assays described here reveals a mechanism of substrate selectivity in the SLC6 family of neurotransmitter transporters. We show that the rotameric state of a volumetric sensor in the substrate binding site is allosterically coupled to conformation...
Article
Full-text available
Metabotropic glutamate receptors (mGluRs) are class C, synaptic G protein-coupled receptors (GPCRs) that contain large extracellular ligand binding domains (LBDs) and form constitutive dimers. Despite the existence of a detailed picture of inter-LBD conformational dynamics and structural snapshots of both isolated domains and full-length receptors,...
Article
Full-text available
Ribosome biogenesis is a canonical hallmark of cell growth and proliferation. Here we show that execution of Epithelial-to-Mesenchymal Transition (EMT), a migratory cellular program associated with development and tumor metastasis, is fueled by upregulation of ribosome biogenesis during G1/S arrest. This unexpected EMT feature is independent of spe...
Article
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The coronary vasculature is crucial for normal heart function, yet much remains to be learned about its development, especially the maturation of coronary arterial endothelium. Here, we show that endothelial inactivation of ADAM10, a key regulator of Notch signaling, leads to defects in coronary arterial differentiation, as evidenced by dysregulate...
Article
Full-text available
The HIV-1 envelope glycoprotein (Env) trimer mediates cell entry and is conformationally dynamic1–8. Imaging by single-molecule fluorescence resonance energy transfer (smFRET) has revealed that, on the surface of intact virions, mature pre-fusion Env transitions from a pre-triggered conformation (state 1) through a default intermediate conformation...
Article
Full-text available
The evolution of the multi-copy family of ribosomal RNA (rRNA) genes is unique in regard to its genetics and genome evolution. Paradoxically, rRNA genes are highly homogenized within and between individuals, yet they are globally distinct between species. Here, we discuss the implications for models of rRNA gene evolution in light of our recent dis...
Preprint
Full-text available
Neurotransmitter:sodium symporters (NSS) in the SLC6 family terminate neurotransmission by coupling the thermodynamically favorable transport of ions to the thermodynamically unfavorable transport of neurotransmitter back into presynaptic neurons. While a combination of structural, functional, and computational studies on LeuT, a bacterial NSS homo...
Preprint
Full-text available
Natural products that target the eukaryotic ribosome are promising therapeutics to treat a variety of cancers. It is therefore essential to determine their molecular mechanism of action to fully understand their mode of interaction with the target and to inform the development of new synthetic compounds with improved potency and reduced cytotoxicit...