Research Archives - Page 48 of 60 - Yokohama City University

2020-08-12

Structure-Based Functional Modification Study of a Cyanobacterial Chloride Pump for Transporting Multiple Anions

Understanding the structure and functional mechanisms of cyanobacterial halorhodopsin has become increasingly important, given the report that Synechocystis halorhodopsin (SyHR), a homolog of the cyanobacterial halorhodopsin from Mastigocladopsis repens (MrHR), can take up divalent ions, such as SO42−, as well as chloride ions. Here, the crystal structure of MrHR, containing a unique “TSD” chloride ion conduction motif, was determined as a homotrimer at a resolution of 1.9 Å.

2020-08-06

Light Activates Brassinosteroid Biosynthesis to Promote Hook Opening and Petiole Development in Arabidopsis thaliana

Although brassinosteroids (BRs) have been proposed to be negative regulators of photomorphogenesis, their physiological role therein has remained elusive. We studied light-induced photomorphogenic development in the presence of the BR biosynthesis inhibitor, brassinazole (Brz). Hook opening was inhibited in the presence of Brz; this inhibition was reversed in the presence of brassinolide (BL). Hook opening was accompanied by cell expansion on the inner (concave) side of the hook. This cell expansion was inhibited in the presence of Brz but was restored upon the addition of BL. We then evaluated light-induced organ-specific expression of three BR biosynthesis genes, DWF4, BR6ox1 and BR6ox2, and a BR-responsive gene, SAUR-AC1, during the photomorphogenesis of Arabidopsis.

2020-08-04

Acetylated histone H4 tail enhances histone H3 tail acetylation by altering their mutual dynamics in the nucleosome

The structural unit of eukaryotic chromatin is a nucleosome, comprising two histone H2A-H2B heterodimers and one histone (H3-H4)2 tetramer, wrapped around by ∼146 bp of DNA. The N-terminal flexible histone tails stick out from the histone core and have extensive posttranslational modifications, causing epigenetic changes of chromatin. Although crystal and cryogenic electron microscopy structures of nucleosomes are available, the flexible tail structures remain elusive. Using NMR, we have examined the dynamics of histone H3 tails in nucleosomes containing unmodified and tetra-acetylated H4 tails.

2020-07-28

Current national policies for infant universal bacille Calmette-Guerin vaccination were associated with lower mortality from coronavirus disease 2019

An exciting debate has emerged whether bacille Calmette-Guerin (BCG) vaccination is effective for the coronavirus disease 2019 (COVID-19) pandemic. Some advocated that BCG-vaccinated people are less suffered from the virus because BCG vaccination is recommendedin COVID-19 high burden countries. However, the others objected because this seemingly attractive relationship is explainable with confounding factors.