A5050469435- Ion channel regulation and function
- Nicotinic Acetylcholine Receptors Study
- Biochemical and Molecular Research
- Chemical Synthesis and Analysis
- Pneumocystis jirovecii pneumonia detection and treatment
- Receptor Mechanisms and Signaling
- Lanthanide and Transition Metal Complexes
- Advanced NMR Techniques and Applications
- Protein Structure and Dynamics
- Advanced Breast Cancer Therapies
- HIV/AIDS drug development and treatment
- Advanced MRI Techniques and Applications
- Mass Spectrometry Techniques and Applications
- Antimicrobial Peptides and Activities
- Parasites and Host Interactions
- Ubiquitin and proteasome pathways
- Radiopharmaceutical Chemistry and Applications
- Venomous Animal Envenomation and Studies
- CAR-T cell therapy research
- Rocket and propulsion systems research
- Advanced Combustion Engine Technologies
- Chemical Reactions and Isotopes
- Cancer therapeutics and mechanisms
- RNA and protein synthesis mechanisms
- Cellular transport and secretion
Harvard University
2017-2022
Dana-Farber Cancer Institute
2017-2022
CT Group Of Institutions
2022
Dayanand Medical College & Hospital
2022
Monash University
2010-2021
Australian Regenerative Medicine Institute
2015-2016
Commonwealth Scientific and Industrial Research Organisation
2010-2014
Indian Institute of Chemical Biology
2007
Banaras Hindu University
2006-2007
Immune checkpoint blockade, exemplified by antibodies targeting the PD-1 receptor, can induce durable tumor regressions in some patients. To enhance efficacy of existing immunotherapies, we screened for small molecules capable increasing activity T cells suppressed PD-1. Here, show that short-term exposure to small-molecule inhibitors cyclin-dependent kinases 4 and 6 (CDK4/6) significantly enhances T-cell activation, contributing antitumor effects vivo, due part derepression NFAT family...
Structural studies of proteins and protein-ligand complexes by nuclear magnetic resonance (NMR) spectroscopy can be greatly enhanced site-specific attachment lanthanide ions to create paramagnetic centers. In particular, pseudocontact shifts (PCS) generated lanthanides contain important unique long-range structure information. Here, we present a high-affinity binding tag that attached single cysteine residues proteins. The new has many advantageous features are not available in this...
The voltage-gated potassium (Kv) 1.3 channel is widely regarded as a therapeutic target for immunomodulation in autoimmune diseases. ShK-186, selective inhibitor of Kv1.3 channels, ameliorates diseases rodent models, and human phase 1 trials this agent healthy volunteers have been completed. In study, we identified characterized large family Stichodactyla helianthus toxin (ShK)-related peptides parasitic worms. Based on phylogenetic analysis, 2 worm were selected study: AcK1, 51-residue...
HsTX1 toxin, from the scorpion Heterometrus spinnifer, is a 34-residue, C-terminally amidated peptide cross-linked by four disulfide bridges. Here we describe new analogues with an Ala, Phe, Val or Abu substitution at position 14. Complexes of voltage-gated potassium channels Kv1.3 and Kv1.1 were created using docking molecular dynamics simulations, then umbrella sampling simulations performed to construct potential mean force (PMF) ligand calculate corresponding binding free energy for most...
The voltage-gated potassium channel Kv1.3 is a well-established target for treatment of autoimmune diseases. ShK peptide from sea anemone one the most potent blockers but its application as therapeutic agent diseases limited by lack selectivity against other Kv channels, in particular Kv1.1. Accurate models Kv1.x-ShK complexes suggest that specific charge mutations on could considerably enhance specificity Kv1.3. Here we evaluate K18A mutation ShK, and calculate change binding free energy...
ShK, from the sea anemone Stichodactyla helianthus, is a 35-residue disulfide-rich peptide that blocks voltage-gated potassium channel Kv1.3 at ca. 10 pM and related Kv1.1 16 pM. We developed an analog of this peptide, ShK-186, which currently in Phase 1b-2a clinical trials for treatment autoimmune diseases such as multiple sclerosis rheumatoid arthritis. While ShK-186 displays >100-fold improvement selectivity over compared with there considerable interest developing peptides even...
α-Conotoxin RgIA is both an antagonist of the α9α10 nicotinic acetylcholine receptor (nAChR) subtype and inhibitor high-voltage-activated N-type calcium channel currents. has therapeutic potential for treatment pain, but reduction disulfide bond framework under physiological conditions represents a liability clinical applications. We synthesized four analogues that replaced native pairs with nonreducible dicarba bridges. Solution structures were determined by NMR, activity assessed against...
VPS29 is a key component of the cargo-binding core complex retromer, protein assembly with diverse roles in transport receptors within endosomal system. has fold related to metal-binding phosphatases and mediates interactions between retromer other regulatory proteins. In this study we examine functional mammalian VPS29, using X-ray crystallography NMR spectroscopy. We find that although can coordinate metal ions Mn2+ Zn2+ both putative active site at locations, affinity for metals low, lack...
Conotoxins (CTxs) selectively target a range of ion channels and receptors, making them widely used tools for probing nervous system function. have been previously grouped into superfamilies according to signal sequence families based on their cysteine framework biological target. Here we describe the cloning characterization new conotoxin, from Conus vexillum, named αB-conotoxin VxXXIVA. The peptide does not belong any described conotoxin superfamily its arrangement Cys residues is unique...
All the way with IDA! Attachment of iminodiacetic acid (IDA) to a protein helix creates rigid lanthanide binding site that can be exploited for paramagnetic NMR spectroscopy (see picture). Pseudo-contact shifts (PCSs) larger than 8 ppm are achievable tag, and metal exchange is sufficiently fast enable signal assignment by 15Nz spectroscopy, eliminating need an initial model. Detailed facts importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but...
Significance Intrinsically disordered proteins (IDPs) have attracted significant attention due to their roles in crucial cellular processes. NMR is the only technique that allows study of IDPs at atomic-level resolution. However, narrow chemical shift dispersion, rapid exchange with solvent, and high proline content challenge conventional 1 H-detected experiments. Here, we report development a suite 3D experiments based on 15 N direct detection harnesses slow relaxation larger dispersion...
Abstract Dihydropteroate synthase (DHPS) is an enzyme of the folate biosynthesis pathway, which catalyzes formation 7,8‐dihydropteroate (DHPt) from 6‐hydroxymethyl‐7,8‐dihydropterin pyrophosphate (DHPPP) and para ‐aminobenzoic acid (pABA). DHPS long‐standing target sulfonamide class antibiotics that compete with pABA. In wake sulfa drug resistance, targeting structurally rigid (and more conserved) pterin site has been proposed as alternate strategy to inhibit in wild‐type resistant strains....
Attachment of two nitrilotriacetic acid-based ligands to a protein α-helix in an i, i + 4 configuration produces octadentate chelating motif that is able bind paramagnetic lanthanide ions rigidly and with high affinity, leading large pseudocontact shifts residual dipolar couplings the NMR spectrum.
The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported.
The protein SPSB2 mediates proteosomal degradation of inducible nitric oxide synthase (iNOS). Inhibitors SPSB2-iNOS interaction may prolong the lifetime iNOS and thereby enhance killing persistent pathogens. We have designed a cyclic peptide, Ac-c[CVDINNNC]-NH2, containing key sequence motif mediating interaction, which binds to binding site on with Kd 4.4 nM, as shown by SPR, [(1)H,(15)N]-HSQC, (19)F NMR. An in vitro assay macrophage cell lysates showed complete inhibition interactions...
The voltage-gated potassium channel Kv1.3 is an important target for the treatment of autoimmune diseases and asthma. Blockade by sea anemone peptide K⁺-channel toxin from Stichodactyla helianthus (ShK) inhibits proliferation effector memory T lymphocytes ameliorates in animal models. However, lack selectivity ShK over Kv1.1 subtype has driven a search Kv1.3-selective analogues. In present study, we describe N-terminally extended analogues that contain negatively-charged Glu, designed to...
Abstract Therapeutically relevant proteins such as GPCRs, antibodies and kinases face clear limitations in NMR studies due to the challenges site‐specific isotope labeling deuteration eukaryotic expression systems. Here we describe an efficient simple method observe methyl groups of leucine residues expressed bacterial, or cell‐free systems without modification protocol. The relies on stereo‐selective 13 C‐labeling that alleviates need for additional protein. spectroscopic benefits “local”...
The first structural and biophysical data on the folate biosynthesis pathway enzyme drug target, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (SaHPPK), from pathogen Staphylococcus aureus is presented. HPPK second essential in catalysing pyrophosphoryl transfer cofactor (ATP) to substrate (6-hydroxymethyl-7,8-dihydropterin, HMDP). In-silico screening identified 8-mercaptoguanine which was shown bind with an equilibrium dissociation constant, Kd, of ∼13 µM as measured by isothermal...
The peptide HsTX1[R14A] is a potent and selective blocker of the voltage-gated potassium channel Kv1.3, which highly promising target for treatment autoimmune diseases other conditions. In order to assess biodistribution this peptide, it was conjugated with NOTA radiolabelled copper-64. [64Cu]Cu-NOTA-HsTX1[R14A] synthesised in high radiochemical purity yield. radiotracer evaluated vitro vivo. PET studies after intravenous subcutaneous injections showed similar patterns kinetics. hydrophilic...
As the second essential enzyme of folate biosynthetic pathway, potential antimicrobial target, HPPK (6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase), catalyzes Mg(2+-)dependant transfer pyrophosphate from cofactor (ATP) to substrate, 6-hydroxymethyl-7,8-dihydropterin. Recently, we showed that 8-mercaptoguanine (8-MG) bound at substrate site (KD ∼13 µM), inhibited S. aureus (SaHPPK) (IC50 ∼ 41 and determined structure SaHPPK/8-MG complex. Here present synthesis a series guanine...
Inhibitors of the α‐subunit voltage‐gated sodium channel subtype 1.3 (Na V 1.3) are interest as pharmacological tools for study neuropathic pain associated with spinal cord injury and have potential therapeutic applications. The recently described μ‐conotoxin Bu IIIB (μ‐Bu ) from Conus bullatus was shown to block Na submicromolar potency ( K d = 0.2 μ m ), making it one most potent peptidic inhibitors this date. However, oxidative folding μ‐Bu results in numerous isoforms, difficult obtain...
Abstract ShK is a 35‐residue peptide that binds with high affinity to human voltage‐gated potassium channels through conserved K‐Y dyad. Here we have employed NMR measurements of backbone‐amide 15 N spin‐relaxation rates investigate motions the backbone. Although rigid on ps ns timescale, increased linewidths observed for 11 resonances identify chemical or conformational exchange contributions spin relaxation. Relaxation dispersion profiles indicate between major and minor conformers occurs...
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK), an enzyme from the folate biosynthesis pathway, catalyzes pyrophosphoryl transfer ATP to 6-hydroxymethyl-7,8-dihydropterin and is a yet-to-be-drugged antimicrobial target. Building on our previous discovery that 8-mercaptoguanine (8MG) inhibitor of Staphylococcus aureus HPPK (SaHPPK), we have identified characterized binding S8-functionalized derivative (3). X-ray structures both SaHPPK/3/cofactor analogue ternary SaHPPK/cofactor...