Structural Modeling of Djenkolic Acid with Sulfur Replaced by Selenium and Tellurium

Abstract

Abstract:The comparative structural modeling of djenkolic acid and its derivatives containing selenium and tellurium in chalcogen sites (Ch = Se, Te) has provided detailed information about the bond lengths and bond angles, filling the gap in what we know about the structural characteristics of these aminoacids. The investigation using the molecular mechanics technique with good approximation confirmed the available information on X-ray refinements for the related compounds methionine and selenomethionine, as well as for an estimate made earlier for telluromethionine. It was shown that the Ch-C(3) and Ch-C(4) bond lengths grow in parallel with the increasing anionic radii. Although the distances C-C, C-O, and C-N are very similar, the geometry of conformers is quite different owing to the possibility of rotation about four carbon atoms, hence the remarkable variability observed in dihedral angles. It was shown that the compounds contain a rigid block with two Ch atoms connected through a methylene group. The standard program Gaussian 03 with graphical interface Gaussview 4.1.2 has proved to be satisfactory tool for the structural description of less-common bioactive compositions when direct X-ray results are absent.

Adaptive Laboratory Evolution Reveals the Selenium Efflux Process To Improve Selenium Tolerance Mediated by the Membrane Sulfite Pump in Saccharomyces cerevisiae

“…Fzf1p is composed of five zinc fingers (ZFs) and plays a positive role in the transcription of ssu1 ( 26 ). Given the tight regulatory relationship between ssu1 and fzf1 and that they were both mutated in most evolved groups within several positions coincidentally, these results suggested that ssu1 and fzf1 are likely to perform homogeneous functions in selenium metabolism combined with the chemical similarity between selenium and sulfur ( 27 – 29 ). Therefore, we investigated the latent functions of ssu1 and fzf1 in the selenium tolerance of yeasts and then confirmed that both ssu1 and fzf1 indeed play vital roles, while the other four most frequently mutated genes ( fcy21 , cos9 , mnn4 , and bio3 ) screened by sequencing analysis were found to be irrelevant for selenium tolerance (Fig.…”