Crystal Structure Analysis Reveals Functional Flexibility in the Selenocysteine-Specific tRNA from Mouse

Selenocysteine tRNAs (tRNA(Sec)) exhibit a number of unique identity elements that are recognized specifically by proteins of the selenocysteine biosynthetic pathways and decoding machineries. Presently, these identity elements and the mechanisms by which they are interpreted by tRNA(Sec)-interacting factors are incompletely understood.We applied rational mutagenesis to obtain well diffracting crystals of murine tRNA(Sec). tRNA(Sec) lacking the single-stranded 3'-acceptor end ((ΔGCCA)RNA(Sec)) yielded a crystal structure at 2.0 Å resolution. The global structure of (ΔGCCA)RNA(Sec) resembles the structure of human tRNA(Sec) determined at 3.1 Å resolution. Structural comparisons revealed flexible regions in tRNA(Sec) used for induced fit binding to selenophosphate synthetase. Water molecules located in the present structure were involved in the stabilization of two alternative conformations of the anticodon stem-loop. Modeling of a 2'-O-methylated ribose at position U34 of the anticodon loop as found in a sub-population of tRNA(Sec)in vivo showed how this modification favors an anticodon loop conformation that is functional during decoding on the ribosome. Soaking of crystals in Mn(2+)-containing buffer revealed eight potential divalent metal ion binding sites but the located metal ions did not significantly stabilize specific structural features of tRNA(Sec).We provide the most highly resolved structure of a tRNA(Sec) molecule to date and assessed the influence of water molecules and metal ions on the molecule's conformation and dynamics. Our results suggest how conformational changes of tRNA(Sec) support its interaction with proteins

An Analysis of Hospitality of Front Office Staffs at Favehotel Bandung. Villar Sherlin Agustina:177010012

Hospitality industry has developed along with the needs of the community to fulfill their activities. Especially in this Pandemic era, many people choose to stay at hotels. The front office has an important role in hotel operations, namely as the main gate for reception of guests. Front Office staff must have an attractive and good first impression in the eyes of guests. The object of this research is the Front Office Staff at Favehotel Bandung. This research was conducted to determine the friendliness of the Front Office Staff at Favehotel Bandung. The writer makes a research entitled “An Analysis of Hospitality of Front Office Staff Favehotel Bandung”. The research method in this study uses descriptive qualitative research methods as research procedures that produce descriptive data in the form of written or spoken words from people or sources and observed behavior. The results of this study indicate that the Front Office Staff at favehotel Bandung work as much as possible to make guests comfortable while staying at the hotel. The management of favehotel Bandung is also very concerned about the friendliness of their staff, especially in the Front Office Department. It is evident from the guests who repeat come to Favehotel Bandung because their Front Office is very trustworthy in matters of privacy and guest comfort. Front Office Staff at favehotel Bandung are very able to maintain their manners from greeting guests, clothes, appearance and always looks friendly. Keywords: Hospitality, Front Office, Hote

Diversity-oriented synthesis yields novel multistage antimalarial inhibitors

Antimalarial drugs have thus far been chiefly derived from two sources—natural products and synthetic drug-like compounds. Here we investigate whether antimalarial agents with novel mechanisms of action could be discovered using a diverse collection of synthetic compounds that have three-dimensional features reminiscent of natural products and are underrepresented in typical screening collections. We report the identification of such compounds with both previously reported and undescribed mechanisms of action, including a series of bicyclic azetidines that inhibit a new antimalarial target, phenylalanyl-tRNA synthetase. These molecules are curative in mice at a single, low dose and show activity against all parasite life stages in multiple in vivo efficacy models. Our findings identify bicyclic azetidines with the potential to both cure and prevent transmission of the disease as well as protect at-risk populations with a single oral dose, highlighting the strength of diversity-oriented synthesis in revealing promising therapeutic targets