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Effects of arsenic binding on [Beta]-hairpin are studied by introducing pairs of cysteines into a model monomeric [Beta]-hairpin to yield a family of peptides. Results reveal that arsenic binding could both favor and disfavor helical and [Beta]-hairpin structures depending on the placement of cysteine residues and the plasticity of the secondary structural elements to insertion of a monoalkylated As(III) derivative.

As(III) displays a wide range of effects in cellular chemistry. Model alpha-helical peptides containing two cysteine (Cys) residues in various sequential arrangements and spatial locations is utilized to study the structural effects of arsenic binding.

Nearly 262 empirically based articles, published between 1980 and 1987, were used to conduct a methodical descriptive review to identify difficulties in estimation, to explore the nature of evaluation insufficiencies and offer suggestions for the future. Standardized tools such as the Inventory of Socially Supportive Behavior, the Interpersonal Support Evaluation List and the Arizona Social Support Interview Schedule should be used, because they include the operational facets of social support.

Mono-, di, and trimethyl ester analogues of tris(2-carboxyethyl)phosphine were synthesized to evaluate the role of carboxylate anions in the reduction mechanism, and to expand the range of phosphine reductants. Model disulfides, including a fluorescent disulfide-containing peptide (H3N(super +)-VTWCGACKM-NH2), and with protein disulfide bonds in thioredoxin and sulfhydryl oxidase, are used to determine the effectiveness of all four phosphines relative to the dithiothreitol.

The title quaternary ammonium salt, C18H24NS2+·Cl−, was reported several decades ago, but its structure was not determined at the time. The crystal structure displays extensive hydrogen bonding, linking cations and anions into infinite chains. There are two cations and two anions in the asymmetric unit. [ABSTRACT FROM AUTHOR]