A5040079259- HIV Research and Treatment
- RNA and protein synthesis mechanisms
- HIV/AIDS drug development and treatment
- Viral Infections and Outbreaks Research
- Monoclonal and Polyclonal Antibodies Research
- RNA modifications and cancer
- SARS-CoV-2 and COVID-19 Research
- Virus-based gene therapy research
- Animal Virus Infections Studies
- RNA Research and Splicing
- Viral gastroenteritis research and epidemiology
- Viral Infections and Vectors
- Bacteriophages and microbial interactions
- Influenza Virus Research Studies
- Advanced Fluorescence Microscopy Techniques
- Cytomegalovirus and herpesvirus research
- Immune Cell Function and Interaction
- DNA and Nucleic Acid Chemistry
- Virology and Viral Diseases
- vaccines and immunoinformatics approaches
- Hepatitis B Virus Studies
- Advanced biosensing and bioanalysis techniques
- Respiratory viral infections research
- Peptidase Inhibition and Analysis
- HIV/AIDS Research and Interventions
University of Massachusetts Chan Medical School
2020-2025
UMass Memorial Medical Center
2024
Monash University
2023
Tufts University
2015-2021
Yale University
2012-2015
Cornell University
2007-2011
University of Vermont
2004
Clark University
1999
University of Warwick
1999
McGill University
1999
The HIV-1 envelope (Env) mediates viral entry into host cells. To enable the direct imaging of conformational dynamics within Env, we introduced fluorophores variable regions glycoprotein gp120 subunit and measured single-molecule fluorescence resonance energy transfer context native trimers on surface virions. Our observations revealed unliganded Env to be intrinsically dynamic, transitioning between three distinct prefusion conformations, whose relative occupancies were remodeled by...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects cells through binding to angiotensin-converting enzyme (ACE2). This interaction is mediated by the receptor-binding domain (RBD) of viral spike (S) glycoprotein. Structural and dynamic data have shown that S can adopt multiple conformations, which controls exposure ACE2-binding site in RBD. Here, using single-molecule Förster resonance energy transfer (smFRET) imaging, we report effects ACE2 antibody on conformational...
Organic fluorophores common to fluorescence-based investigations suffer from unwanted photophysical properties, including blinking and photobleaching, which limit their overall experimental performance. Methods control such processes are particularly important for single-molecule fluorescence resonance energy transfer imaging where uninterrupted, stable is paramount. Fluorescence FRET-based assays have been carried out on dye-labeled DNA RNA-based systems quantify the effect of...
ABSTRACT Primary human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimers [(gp120/gp41) 3 ] typically exist in a metastable closed conformation (state 1). Binding the CD4 receptor triggers Env to undergo extensive conformational changes mediate entry. We identified specific gp120 residues that restrain state 1. Alteration of these restraining destabilized 1, allowing populate functional 2) intermediate between 1 and full CD4-bound 3). Increased 2 occupancy was associated with...
HIV-1 entry into cells requires binding of the viral envelope glycoprotein (Env) to receptor CD4 and coreceptor. Imaging individual Env molecules on native virions shows trimers be dynamic, spontaneously transitioning between three distinct well-populated conformational states: a pre-triggered (State 1), default intermediate 2) three-CD4-bound conformation 3), which can stabilized by coreceptor-surrogate antibody 17b. Here, using single-molecule Fluorescence Resonance Energy Transfer...
The SARS-CoV-2 spike (S) protein variant D614G supplanted the ancestral virus worldwide in a matter of months. Here we show that was more infectious than form on human lung cells, colon and cells rendered permissive by ectopic expression various mammalian ACE2 orthologs. Nonetheless, affinity for reduced due to faster dissociation rate. Assessment S trimer cryo-electron microscopy showed disrupts critical interprotomer contact this dramatically shifts conformation toward an ACE2-binding...
The Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for entry into cells. Following endocytosis of EBOV, the GP1 domain cleaved by cellular cathepsins in acidic endosomes, removing glycan cap and exposing binding site Niemann-Pick C1 (NPC1) receptor. NPC1 to entry. How this interaction translates GP2 domain-mediated viral endosomal membranes not known. Here, using bulk fluorescence dequenching assay single-molecule Förster resonance energy transfer...
Conformational dynamics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein (S) mediate exposure binding site for cellular receptor, angiotensin-converting enzyme (ACE2). The N-terminal domain (NTD) S binds terminal sialic acid (SA) moieties on cell surface, but functional role this interaction in virus entry is unknown. Here, we report that NTD-SA enhances both S-mediated attachment and ACE2 binding. Through single-molecule Förster resonance energy...
The mechanism of substrate translocation through the ribosome is central to rapid and faithful translation mRNA into proteins. rate-limiting step in an unlocking process that includes formation “unlocked” intermediate state, which requires convergence large-scale conformational events within including tRNA hybrid states formation, closure ribosomal L1 stalk domain, subunit ratcheting. Here, by imaging pretranslocation complex from multiple structural perspectives using two- three-color...
HIV-1 cell-to-cell transmission allows for 2–3 orders of magnitude more efficient viral spread than cell-free dissemination. The high local multiplicity infection (MOI) observed at cell-cell contact sites may lower the efficacy antiretroviral therapies (ART). Here we test commonly used inhibitors against and transmission. We demonstrate that, while some nucleoside-analog reverse transcriptase (NRTI) are less effective transmission, most non-nucleoside-analog (NNRTI), entry protease remain...