Crystal Structure and Mutagenesis of an XYP Subfamily Cyclodipeptide Synthase Reveal Key Determinants of Enzyme Activity and Substrate Specificity.

Cyclodipeptide synthases (CDPSs) catalyze the synthesis of diverse cyclodipeptides (CDPs) by utilizing two aminoacyl-tRNA (aa-tRNA) substrates in a sequential ping-pong reaction mechanism. Numerous CDPSs have been characterized to provide precursors for diketopiperazines (DKPs) with diverse structural characteristics and biological activities. BcmA, belonging to the XYP subfamily, is a cyclo(l-Ile-l-Leu)-synthesizing CDPS involved in the biosynthesis of the antibiotic bicyclomycin.

TMSBr-mediated solvent- and work-up-free synthesis of α-2-deoxyglycosides from glycals.

The thio-additions of glycals were efficiently promoted by a stoichiometric amount of trimethylsilyl bromide (TMSBr) to produce S-2-deoxyglycosides under solvent-free conditions in good to excellent yields. In addition, with triphenylphosphine oxide as an additive, the TMSBr-mediated direct glycosylations of glycals with a large range of alcohols were highly α-selective.

Thyroid metastasis from breast cancer presenting with diffuse microcalcifications on sonography: a case report.

Microcalcifications are frequently associated with papillary thyroid cancers. Metastatic nodules from extrathyroid malignancies may mimic primary thyroid neoplasm on sonography, but do not present with microcalcifications. We report the case of a 45-year-old woman with a history of invasive ductal carcinomas of bilateral breasts, status post surgery and neoadjuvant chemotherapy.