The VPS4 AAA ATPases function both in endosomal vesicle formation and the budding of many enveloped RNA viruses, including HIV-1. proteins act by binding catalyzing release membrane-associated ESCRT-III protein lattice, thereby allowing multiple rounds sorting formation. Here, we report solution structure N-terminal VPS4A m icrotubule i nteracting t ransport (MIT) domain demonstrate that MIT binds C-terminal half protein, CHMP1B ( K d = 20 ± 13 μM). forms an asymmetric three-helix bundle...

The endosomal sorting complexes required for transport (ESCRT) machinery mediates the physical separation between daughter cells during cytokinetic abscission. This process is regulated by abscission checkpoint, a genome protection mechanism that relies on Aurora B and ESCRT-III subunit CHMP4C to delay in response chromosome missegregation. In this study, we show Unc-51-like kinase 3 (ULK3) phosphorylates binds subunits via tandem MIT domains, thereby, delays lagging chromosomes, nuclear...

Catalytically essential side-chain radicals have been recognized in a growing number of redox enzymes. Here we present novel approach to study this class cofactors. Our aim is construct de novo protein, radical maquette, that will provide protein framework which investigate how are generated, controlled, and directed toward catalysis. A tryptophan tyrosine denoted α3W1 α3Y1, respectively, synthesized. α3Y1 contain 65 residues each molecular masses 7.4 kDa. The proteins differ only residue...

Conformational changes, including local protein folding, play important roles in protein-DNA interactions. Here, studies of the transcription factor Ets-1 provided evidence that unfolding also can accompany DNA binding. Circular dichroism and partial proteolysis showed secondary structure DNA-binding domain is unchanged presence DNA. In contrast, allosterically induced an α helix lies within a flanking region involved negative regulation These findings suggest structural basis for...

The newly described yeast endosomal sorting complexes required for transport (ESCRT) protein increased sodium tolerance-1 (Ist1p) binds the late-acting ESCRT proteins Did2p/charged MVB (CHMP) 1 and Vps4p exhibits synthetic vacuolar defects when combined with mutations in Vta1p/LIP5-Vps60p/CHMP5 complex. Here, we report that human IST1 also functions pathway is efficient abscission during HeLa cell cytokinesis. binding interactions VPS4, CHMP1, LIP5, ESCRT-I were characterized, IST1-VPS4...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNMR studies of defensin antimicrobial peptides. 2. Three-dimensional structures rabbit NP-2 and human HNP-1Arthur Pardi, Xiao Lu Zhang, Michael E. Selsted, Jack J. Skalicky, Ping F. YipCite this: Biochemistry 1992, 31, 46, 11357–11364Publication Date (Print):November 1, 1992Publication History Published online1 May 2002Published inissue 1 November 1992https://pubs.acs.org/doi/10.1021/bi00161a013https://doi.org/10.1021/bi00161a013research-articleACS...

Interleukin-1 receptor antagonist (IL-1ra), an IL-1 family member, binds with high affinity to the type I (IL-1RI), blocking binding but not inducing IL-1-like response. Extensive site-directed mutagenesis has been used identify residues in IL-1ra and IL-1β involved IL-1RI. These analyses have revealed presence of two discrete sites on IL-1β. Only one these is present IL-1ra, consisting Trp-16, Gln-20, Tyr-34, Gln-36, Tyr-147. Interestingly, absent second site at location major structural...

Building bridges: The use of diselenide and selectively ((15)N/(13)C)-labeled disulfide bridges is combined to give improvements in oxidative folding mapping. Conotoxin analogues, each with a pair selenocysteines (Sec) labeled cysteines (see scheme, red), exhibited significantly improved the allow correctly folded species be rapidly identified by NMR spectroscopy.

The 12 related human ESCRT-III proteins form filaments that constrict membranes and mediate fission, including during cytokinetic abscission. C-terminal tails of polymerized subunits also bind contain Microtubule-Interacting Trafficking (MIT) domains. MIT domains can interact with in many different ways to create a complex binding code is used recruit essential cofactors sites ESCRT activity. Here, we have comprehensively quantitatively mapped the interactions between all known 19...

Theopapuamide (1), a new cytotoxic peptide, has been isolated from the lithistid sponge Theonella swinhoei Papua New Guinea. The structure was established by analysis of NMR, mass spectrometry, and chemical methods. undecapeptide (1) contains several unusual amino acid residues, which occurrence β-methoxyasparagine 4-amino-5-methyl-2,3,5-trihydroxyhexanoic (Amtha) is unprecedented in natural peptides. Compound 1 also an amide-linked fatty moiety, 3-hydroxy-2,4,6-trimethyloctanoic (Htoa)....

Translation of the hepatitis C virus (HCV) RNA is initiated from a highly structured internal ribosomal entry site (IRES) in 5′ untranslated region (5′ UTR) genome. An important structural feature native an approximately 90° helical bend localized to domain IIa that positions apical loop IIb IRES near 40S E-site promote eIF2-GDP release, facilitating 80S ribosome assembly. We report here NMR structure construct complex with potent small-molecule inhibitor HCV replication. Molecular dynamics...

Structural and functional studies of small, disulfide-rich peptides depend on their efficient chemical synthesis folding. A large group derived from animals plants contains the Cys pattern C-C-CC-C-C that forms inhibitory cystine knot (ICK) or knottin motif. Here we report effect site-specific incorporation pairs selenocysteine residues oxidative folding activity omega-conotoxin GVIA, a well-characterized ICK-motif peptidic antagonist voltage-gated calcium channels. Three selenoconotoxin...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDesign of a Unique Protein Scaffold for MaquettesBrian R. Gibney, Francesc Rabanal, Jack J. Skalicky, A. Joshua Wand, and P. Leslie DuttonView Author Information The Johnson Research Foundation, Department Biochemistry Biophysics, University Pennsylvania Philadelphia, 19104 Departments Chemistry, Biological Sciences, Biophysical Sciences Center Structural Biology State New York Buffalo, 14260−3000 Cite this: Am. Chem. Soc. 1997, 119, 9,...

An iterative redesign protocol for the transformation of a non-native peptide into series nativelike proteins derived from elementary considerations biological evolution coupled with 1H NMR as an artificial selection criterion is presented. Each three heptad d position leucines in helix−helix interfaces prototype heme protein maquette, [H10H24]2 or (α-SS-α)2, were replaced unit modification per helix by more conformationally restricted β-branched and aromatic amino acids. The secondary...

The solution structure of a de novo designed disulfide-bridged two-α-helix peptide that self-assembles to form 2-fold symmetric four-α-helix bundle protein (α'-SS-α')2 has been solved by NMR spectroscopy. 33-residue peptide, (α'-SH), is the basic building block recombinantly expressed. three-dimensional asymmetric unit determined using interproton distance restraints derived from nuclear Overhauser effect (NOE), covalent torsion angle three bond scalar coupling constants, and longer range...

We have characterized, for the first time, motional modes of a protein dissolved in supercooled water: flipping kinetics phenylalanyl and tyrosinyl rings 6 kDa BPTI been investigated by NMR at temperatures between −3 −16.5 °C. At T = −15 °C, ring-flipping rate constants Tyr 23, 35, Phe 45 are smaller than 2 s-1, i.e., flip-broadening aromatic lines is reduced beyond detection averaging NOEs through abolished. This allows neat distinct NOE sets individual 1H spins. In contrast, 4, 10, 21, 22,...

Abstract Several members of the ets gene family transcription factors show negative regulation DNA binding by intramolecular interactions. A structural mechanism for this auto‐inhibition is investigated using a 161‐residue N‐terminal deletion mutant murine Ets‐1, Ets‐1ΔN280. This protein shows similar reduced affinity as native Ets‐1 because it contains ETS domain in context flanking amino‐ and carboxy‐terminal regions that together mediate repression binding. The secondary structure...

Hydroxylation of proline residue occurs in specific peptides and proteins derived from plants animals, but the functional role this modification has been characterized primarily collagen. Marine cone snails produce disulfide-rich that have undergone a plethora posttranslational modifications, including hydroxylation. Although Conus extensively utilize hydroxylation, consequences remain largely unexplored. In work, we investigated function 4-hydroxyproline (Hyp) conotoxins three distinct gene...

Disulfide-rich peptides represent a megadiverse group of natural products with very promising therapeutic potential. To accelerate their functional characterization, high-throughput chemical synthesis and folding methods are required, including efficient mapping multiple disulfide bridges. Here, we describe novel approach for such apply it to three-disulfide-bridged conotoxin, μ-SxIIIA (from the venom Conus striolatus), whose discovery is also reported here first time. was chemically...

A maleimide nitroxide spin-label (MAL-6) linked to a cysteine in the hydrophobic core and coproporphyrin I (CP) appended on N-terminus of synthetic helix−loop−helix peptide ([α2]) have been used examine designed self-association four-helix bundle ([α2]2), focusing topology stability rotational dynamics spin-label. Gel-permeation chromatography demonstrated that [α2] modified with ([MAL-6-α2]), ([CP-α2]) plus ([CP-MAL-6-α2]) self-associate into four helix bundles solution as designed....