The author would like to express his appreciation to Professor Ephraim Katchalski for his hospitality, to Professor Michael Sela for samples from his collection and for valuable discussion, to Professor Franz Sondheimer for the use of a spectrophotometer, and to Dr. Israel Schechter and Mr. Shmuel Shaltiel for valuable advice. Abbreviations used are: pTR, poly-L-tyrosyl ribonuclease; pApTR-L, l...

The synthesis and characterization of an isomorphous series of copper-containing microporous metal-organic frameworks (MOFs) based on triazolyl isophthalate linkers with the general formula [Cu₄(μ₃-OH)₂(R¹-R²-trz-ia)₃(H₂O)x] are presented. Through size adjustment of the alkyl substituents R¹ and/or R² at the linker, the impact of linker functionalization on structure-property relationships was ...

Abstract The valorization of biomass-derived molecules into commodity chemicals is important for the transition to renewable feedstocks. model platform molecule 2,5-dimethylfuran (2,5-dmf) can be converted value-added aromatics such as benzene, toluene, and xylenes (BTX) over zeolite catalysts. To explore role acid site(s) in BTX selectivity, gallium has been isomorphously substituted framework...

The trace cations could incorporate into the structure of oxidized green rust (Ox-GR), a layered reactive Fe(III) oxyhydroxide formed from rapid oxidation GR, but effects cation incorporation on mineralogical properties and surface reactivity Ox-GR remain unknown. Here, we synthesized Mn- or Al-incorporated by sulfate-bearing GR determined their structure, elemental composition distribution, As...

Abstract Two novel nonlinear optical isomorphous crystals of proline derivatives with alkyne functionality have been obtained (Boc-L-ProNH(CH 2 ) CCH and Boc-cis-4-fluoro-L-ProNH(CH CCH). Both derivatives, which differ only by the substitution a H atom to F atom, adopt same polar columnar right-handed helix arrangement in crystalline state. In addition, adjacent helical columns all point direct...

Structure determination using the single isomorphous replacement (SIR) or single-wavelength anomalous diffraction (SAD) methods with weak derivatives remains very challenging. In a recent structure determination of glycoprotein E2 from bovine viral diarrhea virus, three isomorphous uranium-derivative data sets were merged to obtain partially interpretable initial experimental maps. Small differ...

Substructure-solution and phasing procedures using a combination of anomalous scattering and radiation-damage-induced isomorphous differences have been investigated. The tyrosine residues in thaumatin were iodinated with N-iodosuccinimide in the crystalline form as well as prior to crystallization. Several data sets were collected from both forms and used for substructure solution and phasing u...

An ab initio study of the electronic structures of solid metallotetrabenzoporphyrins (MTBPs) utilized in organic transistors and photovoltaics is presented. Band structures, densities of states, and orbitals are calculated for H2, Cu, Ni, and Zn core substitutions of the unit cell of solid TBP, as deposited via soluble precursors that are thermally annealed to produce polycrystalline, semicondu...

Attempts to determine the X-ray crystal structure of the intact homohexameric arginine repressor/activator from B. subtilis have so far been unsuccessful. The major problem appears to be the lack of an isomorphous heavy-atom derivative with a manageable number of substitution sites. Here it is shown how electron microscopy of thin three-dimensional crystals, the same as those used for the X-ray...