Sampling of structure and sequence space of small protein folds.

Nature only samples a small fraction of the sequence space that can fold into stable proteins. Furthermore, small structural variations in a single fold, sometimes only a few amino acids, can define a protein's molecular function. Hence, to design proteins with novel functionalities, such as molecular recognition, methods to control and sample shape diversity are necessary.

Carbene-Stabilized Disilicon as a Silicon-Transfer Agent: Synthesis of a Dianionic Silicon Tris(dithiolene) Complex.

Reaction of carbene-stabilized disilicon (1) with the lithium-based dithiolene radical (2 ) affords the first dianionic silicon tris(dithiolene) complex (3). Notably, the formation of 3 represents the unprecedented utilization of carbene-stabilized disilicon (1) as a silicon-transfer agent. The nature of 3 was probed by multinuclear NMR spectroscopy, single-crystal X-ray diffraction, and DFT computations.

Direct Sodium Channel Regulation by Calmodulin.

Many aspects of the sophisticated mechanism of sodium channel regulation by Ca and calmodulin remain unresolved and controversial. In this issue of Structure, Johnson et al. (2018) provide compelling structural and functional evidence clarifying considerably how calmodulin engages the inactivation gate of the sodium channel and the consequences for regulation.

Glucose consumption in carbohydrate mixtures by phosphotransferase-system mutants of Escherichia coli.

Escherichia coli lacking the glucose phosphotransferase system (PTS), mannose PTS and glucokinase are supposedly unable to grow on glucose as the sole carbon source (Curtis SJ, Epstein W. J Bacteriol 1975;122:1189-1199). We report that W ptsG manZ glk (ALS1406) grows slowly on glucose in media containing glucose with a second carbon source: ALS1406 metabolizes glucose after that other carbon source, including arabinose, fructose, glycerol, succinate or xylose, is exhausted.