Search results for "N-terminus"
showing 9 items of 9 documents
Structural Basis of TRPV4 N Terminus Interaction with Syndapin/PACSIN1-3 and PIP2
2018
Summary Transient receptor potential (TRP) channels are polymodally regulated ion channels. TRPV4 (vanilloid 4) is sensitized by PIP2 and desensitized by Syndapin3/PACSIN3, which bind to the structurally uncharacterized TRPV4 N terminus. We determined the nuclear magnetic resonance structure of the Syndapin3/PACSIN3 SH3 domain in complex with the TRPV4 N-terminal proline-rich region (PRR), which binds as a class I polyproline II (PPII) helix. This PPII conformation is broken by a conserved proline in a cis conformation. Beyond the PPII, we find that the proximal TRPV4 N terminus is unstructured, a feature conserved across species thus explaining the difficulties in resolving it in previous …
Localization of the N-terminal Domain in Light-harvesting Chlorophyll a/b Protein by EPR Measurements
2005
The conformational distribution of the N-terminal domain of the major light-harvesting chlorophyll a/b protein (LHCIIb) has been characterized by electron-electron double resonance yielding distances between spin labels placed in various domains of the protein. Distance distributions involving residue 3 near the N terminus turned out to be bimodal, revealing that this domain, which is involved in regulatory functions such as balancing the energy flow through photosystems (PS) I and II, exists in at least two conformational states. Models of the conformational sub-ensembles were generated on the basis of experimental distance restraints from measurements on LHCIIb monomers and then checked f…
Staphylococcal α-toxin: the role of the N-terminus in formation of the heptameric pore — a fluorescence study1This work contains parts of the M.D. th…
1997
Staphylococcus aureus alpha-toxin forms heptameric pores on eukaryotic cell membranes. Assembly of the heptamer precedes formation of the transmembrane pore. The latter event depends on a conformational change that drives a centrally located stretch of 15 amino acid residues into the lipid bilayer. A second region of the molecule that has been implicated in the pre-pore to pore transition is the far N-terminus. Here, we used fluorescently labeled single cysteine replacement mutants to analyze the functional role of the far N-terminus of alpha-toxin. Pyrene attached to mutants S3C, I5C and 17C forms excimers within the toxin pore complex. This indicates that the distance of adjacent N-termin…
Histidine residues near the N terminus of staphylococcal alpha-toxin as reporters of regions that are critical for oligomerization and pore formation.
1994
Chemical modification of histidine residues in staphylococcal alpha-toxin leads to loss of functional activity. Site-directed mutants of the toxin in which each of the four histidine residues was replaced by several amino acids were therefore produced. The mutant proteins were purified and characterized. Exchange of H-259 or H-144 was sometimes tolerated without reduction in hemolytic activity. These histidine residues are thus not essential for toxin function. Exchange of H-35 and H-48, however, had marked effects. H-35 mutant toxins bound with high affinity to rabbit erythrocytes but displayed faulty oligomerization and were unable to form pores. H-48 mutant toxins also had severely impai…
The Major Conformational IgE-binding Epitopes of Hevein (Hev b6.02) Are Identified by a Novel Chimera-based Allergen Epitope Mapping Strategy
2002
A novel approach to localize and reconstruct conformational IgE-binding epitope regions of hevein (Hev b6.02), a major natural rubber latex allergen, is described. An antimicrobial protein (AMP) from the amaranth Amaranthus caudatus was used as an immunologically non-IgE-binding adaptor molecule to which terminal or central parts of hevein were fused. Hevein and AMP share a structurally identical core region but have different N-terminal and C-terminal regions. Only 1 of 16 hevein-allergic patients showed weak IgE binding to purified native or recombinant AMP. Chimeric AMP with the hevein N terminus was recognized by IgE from 14 (88%) patients, and chimeric AMP with the hevein C terminus wa…
Characterizing the N-terminal processing motif of MHC class I ligands.
2008
Abstract Most peptide ligands presented by MHC class I molecules are the product of an intracellular pathway comprising protein breakdown in the cytosol, transport into the endoplasmic reticulum, and successive N-terminal trimming events. The efficiency of each of these processes depends on the amino acid sequence of the presented ligand and its precursors. Thus, relating the amino acid composition N-terminal of presented ligands to the sequence specificity of processes in the pathway gives insight into the usage of ligand precursors in vivo. Examining the amino acid composition upstream the true N terminus of MHC class I ligands, we demonstrate the existence of a distinct N-terminal proces…
The yeast histone acetyltransferase A2 complex, but not free Gcn5p, binds stably to nucleosomal arrays.
2000
We have investigated the structural basis for the differential catalytic function of the yeast Gcn5p-containing histone acetyltransferase (HAT) A2 complex and free recombinant yeast Gcn5p (rGcn5p). HAT A2 is shown to be a unique complex that contains Gcn5p, Ada2p, and Ada3p, but not proteins specific to other related HAT A complexes, e.g. ADA, SAGA. Nevertheless, HAT A2 produces the same unique polyacetylation pattern of nucleosomal substrates reported previously for ADA and SAGA, demonstrating that proteins specific to the ADA and SAGA complexes do not influence the enzymatic activity of Gcn5p within the HAT A2 complex. To investigate the role of substrate interactions in the differential …
Response to Comment on “Characterizing the N-Terminal Processing Motif of MHC Class I Ligands”
2008
The possibility that ERAAP plays a role in limiting the presentation of peptides derived from signal peptides may be tempting from an immunologist’s view. In eukaryotic cells, signal peptides have a mean length of 22 amino acids and are removed by signal peptide peptidases from the N terminus of
Uncapping the N-terminus of a ubiquitous His-tag peptide enhances its Cu2+ binding affinity
2019
Metal complexes with an N-terminally free and N-terminally acetylated polyhistidine region of Echis ocellatus venom, with an interesting His-rich motif present in numerous metal binding proteins from all kingdoms of life (DHDHDHHHHHHPGSSV-NH2 and Ac-DHDHDHHHHHHPGSSV-NH2) show the role of the free amino group in the thermodynamic enhancement of Cu2+, Ni2+ and Zn2+ binding. In the studied sequences, Cu2+ can be coordinated by different sets of imidazole rings, and a 3–10 helix is detected in close proximity of Cu2+ binding sites. The complexes are more stable than those with a typical His6-tag, despite a similar copper(II) coordination mode in both cases.