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81.
The adsorption of NO on Ru(001), and its co-adsorption with oxygen, has been investigated using temperature programmed desorption and infra-red reflection-absorption spectroscopy (IRAS). Only one band due to the NO stretch of adsorbed NO could be observed and was assigned to the linearly bound v2 species. Pre-adsorption of oxygen caused surprisingly little effect on the total desorbed flux of NO and its dissociation products in the TPD spectrum. The main effect of oxygen was to shift intensity from the v1 peak to a new desorption peak v1(O), which is accompanied by a splitting in the IRAS spectrum of the v2 species. The absence of the band observed in the “bridging region” in EELS experiments and the small influence of the pre-adsorbed oxygen on the v2 species is discussed in the light of current models for this adsorption system. 相似文献
82.
Measurement of a radiative lifetime of 9.6 ± 1.0 nsec for the SiOA1Π-state is reported. RKR Franck-Condon factors have been computed and, with these, absolute oscillator strengths are calculated. A band system at ∼ 3022Å has been found that may be due to SiO+, but the band is not resolved at our experimental resolution, and identification remains uncertain. The upper state of the carrier of this spectrum has a radiative lifetime of 8.3 ± 0.8 nsec. 相似文献
83.
Inside Back Cover: Infinite Polyiodide Chains in the Pyrroloperylene–Iodine Complex: Insights into the Starch–Iodine and Perylene–Iodine Complexes (Angew. Chem. Int. Ed. 28/2016) 下载免费PDF全文
84.
Lipid nanotube formation from streptavidin-membrane binding 总被引:1,自引:0,他引:1
Liu H Bachand GD Kim H Hayden CC Abate EA Sasaki DY 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):3686-3689
A novel transformation of giant lipid vesicles to produce nanotubular structures was observed upon the binding of streptavidin to biotinylated membranes. Unlike membrane budding and tubulation processes caused by proteins involved with endocytosis and vesicle fusion, streptavidin is known to crystallize at near the isoelectric point (pI 5 to 6) into planar sheets against biotinylated films. We have found, however, that at neutral pH membranes of low bending rigidity (<10kT), such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), spontaneously produce tubular structures with widths ranging from micrometers to below the diffraction limit (<250 nm) and lengths spanning up to hundreds of micrometers. The nanotubes were typically held taut between surface-bound vesicles suggesting high membrane tension, yet the lipid nanotubes exhibited a fluidic nature that enabled the transport of entrained vesicles. Confocal microscopy confirmed the uniform coating of streptavidin over the vesicles and nanotubes. Giant vesicles composed of lipid membranes of higher bending energy exhibited only aggregation in the presence of streptavidin. Routes toward the development of these highly curved membrane structures are discussed in terms of general protein-membrane interactions. 相似文献
85.
Matthew G. Alteen Hayden Peacock Richard W. Meek Jil A. Busmann Sha Zhu Gideon J. Davies Hiroaki Suga David J. Vocadlo 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215671
Glycosyltransferases are a superfamily of enzymes that are notoriously difficult to inhibit. Here we apply an mRNA display technology integrated with genetic code reprogramming, referred to as the RaPID (random non-standard peptides integrated discovery) system, to identify macrocyclic peptides with high binding affinities for O-GlcNAc transferase (OGT). These macrocycles inhibit OGT activity through an allosteric mechanism that is driven by their binding to the tetratricopeptide repeats of OGT. Saturation mutagenesis in a maturation screen using 39 amino acids, including 22 non-canonical residues, led to an improved unnatural macrocycle that is ≈40 times more potent than the parent compound (Kiapp=1.5 nM). Subsequent derivatization delivered a biotinylated derivative that enabled one-step affinity purification of OGT from complex samples. The high potency and novel mechanism of action of these OGT ligands should enable new approaches to elucidate the specificity and regulation of OGT. 相似文献
86.
87.
AbstractNε-methylation of lysine within proteins is a critical biological process that, among other roles, is involved in the control of gene expression. Compounds that recognise Nε-methylated lysine may therefore be useful probes for the study of the associated biological mechanisms and have therapeutic potential. Here, we show that tetracyanoresorcin[4]arene (1) selectively recognises Nε-trimethyllysine and binds to Nε-trimethyllysine within the context of a short peptide. Its binding properties compare favourably to a previously characterised Nε-trimethyllysine binder, p-sulfonatocalix[4]arene (2). We also show that both 1 and 2 inhibit the demethylation of Nε-trimethyllysine within a histone-derived peptide by the histone demethylase KDM4A. 相似文献
88.
Timothy R. Corkish Christian T. Haakansson Peter D. Watson Hayden T. Robinson Prof. Allan J. McKinley Dr. Duncan A. Wild 《Chemphyschem》2021,22(13):1316-1320
The anion photoelectron spectra of Cl−⋅⋅⋅CD3CDO, Cl−⋅⋅⋅(CD3CDO)2, Br−⋅⋅⋅CH3CHO, and I−⋅⋅⋅CH3CHO are presented with electron stabilisation energies of 0.55, 0.93, 0.48, and 0.40 eV, respectively. Optimised geometries of the singly solvated species featured the halide appended to the CH3CHO molecule in-line with the electropositive portion of the C=O bond and having binding energies between 45 and 52 kJ mol−1. The doubly solvated Cl−⋅⋅⋅(CH3CHO)2 species features asymmetric solvation upon the addition of a second CH3CHO molecule. Theoretical detachment energies were found to be in excellent agreement with experiment, with comparisons drawn between other halide complexes with simple carbonyl molecules. 相似文献
89.
Christian T. Haakansson Timothy R. Corkish Peter D. Watson Hayden T. Robinson Terrence Tsui Prof. Allan J. McKinley Dr. Duncan A. Wild 《Chemphyschem》2021,22(9):808-812
A combined experimental and theoretical approach has been used to study intermolecular chalcogen bonding. Specifically, the chalcogen bonding occurring between halide anions and CS2 molecules has been investigated using both anion photoelectron spectroscopy and high-level CCSD(T) calculations. The relative strength of the chalcogen bond has been determined computationally using the complex dissociation energies as well as experimentally using the electron stabilisation energies. The anion complexes featured dissociation energies on the order of 47 kJ/mol to 37 kJ/mol, decreasing with increasing halide size. Additionally, the corresponding neutral complexes have been examined computationally, and show three loosely-bound structural motifs and a molecular radical. 相似文献
90.
Frolova LV Evdokimov NM Hayden K Malik I Rogelj S Kornienko A Magedov IV 《Organic letters》2011,13(5):1118-1121
Privileged medicinal scaffolds based on the structures of tetra- and pentasubstituted 2-aminopyrroles were prepared via one-pot multicomponent reactions of structurally diverse aldehydes and N-(aryl-, hetaryl-, alkylsulfonamido)acetophenones with activated methylene compounds. This methodology was used in a four-step synthesis of alkaloids rigidins A, B, C, and D in overall yields of 61%, 58%, 60%, and 53%, respectively. Of these, rigidins B, C, and D were synthesized for the first time. 相似文献