Negative DNA supercoiling enhances DARS2 binding of DNA-bending protein IHF in the activation of Fis-dependent ATP-DnaA production.

Oscillation of the active form of the initiator protein DnaA (ATP-DnaA) allows for the timely regulation for chromosome replication. After initiation, DnaA-bound ATP is hydrolyzed, producing inactive ADP-DnaA. For the next round of initiation, ADP-DnaA interacts with the chromosomal locus DARS2 bearing binding sites for DnaA, a DNA-bending protein IHF, and a transcription activator Fis.

Stable sugar-chain-immobilized fluorescent nanoparticles for probing lectin and cells.

Sugar chains are important molecules in cellular recognition and signaling, and quantum dots (QDs) are a very powerful tool for in vitro and in vivo imaging. Herein, we report the preparation of stable sugar-chain-immobilized fluorescent nanoparticles (SFNPs) and their application to the analysis of sugar-chain-protein interactions and cellular imaging. SFNPs were easily prepared by mixing CdTe/CdS core/shell QDs with our previously developed sugar-chain-ligand conjugates.