Gosuke Hayashi

The discovery of riboswitching has accelerated research on the interaction between RNA and small organic compounds. It will be important for biologists to artificially and reversibly control gene expression in vivo through the interaction of RNA and small molecules. In this paper, we report that RNA aptamers obtained from in vitro selection in which a photoresponsive short peptide containing the azobenzene moiety with flanking arginine residues on both sides as a ligand provided reversible bindi

In the summer of 2012, 1 year after the nuclear accident in March 2011 at the Fukushima Daiichi nuclear power plant, we examined the effects of gamma radiation on rice at a highly contaminated field of Iitate village in Fukushima, Japan. We investigated the morphological and molecular changes on healthy rice seedlings exposed to continuous low-dose gamma radiation up to 4 µSv h(-1), about 80 times higher than natural background level. After exposure to gamma rays, expression profiles of selected

Modulation of biological networks assembled by diverse interactions among biologically active molecules has provided a platform for innovative biotechnologies. Here, we report RNA aptamers that bind to a photoresponsive peptide (KRAzR; Lys-Arg-azobenzene-Arg) containing azobenzene chromophore, which can change its structure by photoirradiation. Aptamers were identified after 10 cycles of an in vitro selection procedure starting with a DNA library containing a 70 nt random region. Surface plasmon

5-Hydroxymethylcytosine (^hmC) is an essential intermediate in the active DNA demethylation pathway. Here we report a new base-resolution method for measuring ^hmC by combining peroxotungstate-mediated oxidation and sequencing analysis. We reveal that an oxidized product of ^hmC, trihydroxylated thymine (^thT), tolerated the incorporation of dATP as a substrate in the process of DNA polymerase elongation. By comparing the results of Sanger sequencing befor

The application of organometallic compounds for protein science has received attention. Recently, total chemical protein synthesis using transition metal complexes has been developed to produce various proteins bearing site-specific posttranslational modifications (PTMs). However, in general, significant amounts of metal complexes were required to achieve chemical reactions of proteins bearing a large number of nucleophilic functional groups. Moreover, syntheses of medium-size proteins (>20 kDa)

The chemical synthetic route to histone H2A is described. An H2A-H2B dimer, histone octamer, and nucleosome were reconstituted with the synthetic H2A. Fluorescein-labeled H2A and multiply modified H2A, which has three different posttranslational modifications, were also synthesized, and applied to live-cell imaging and in vitro nucleosome stability assays, respectively.

We report selective removals of N-terminal and internal Cys protecting groups using different palladium complexes to facilitate the efficient chemical protein synthesis. Utilizing the orthogonal deprotection pairs, we accomplished chemical synthesis of histone H3 containing trimethylated Lys through the combination of Pd(0)-mediated Alloc deprotection for one-pot multiple peptide ligation and Pd(II)Cl₂-mediated Acm deprotection to recover native Cys residues after desulfurization.

Native chemical ligation (NCL) between the C-terminal peptide thioester and the N-terminal cysteinyl-peptide revolutionized the field of chemical protein synthesis. The difficulty of direct synthesis of the peptide thioester in the Fmoc method has prompted the development of crypto-thioesters that can be efficiently converted into thioesters. Cysteinylprolyl ester (CPE), which is an <i>N</i>-<i>S</i> acyl shift-driven crypto-thioester that relies on an intramolecular <i>O</i>-<i>N</i> acyl shift

Strategies for one-pot peptide ligation enable chemists to access synthetic proteins at a high yield in a short time. Herein, we report a novel one-pot multi-segments ligation strategy using N-terminal thiazolidine (Thz) peptide and a newly designed formaldehyde scavenger. Among the designed 2-aminobenzamide-based aldehyde scavengers, 2-amino-5-methoxy-N',N'-dimethylbenzohydrazide (AMDBH) can remarkably convert Thz into unprotected cysteine at pH 4.0. Furthermore, AMDBH degrades Thz at a conside

Single strand stands out. A polymerase chain reaction (PCR) with a primer containing a mirror image DNA (L-DNA) sequence tag at the 5′-end produced an L-DNA duplex labeled with a single strand of L-DNA of defined sequence. The PCR products could be directly detected on the surface plasmon resonance (SPR) imaging array where the complementary L-DNA sequences were immobilized.

Peptide ligation is an indispensable step in the chemical synthesis of target peptides and proteins that are difficult to synthesize at once by a solid-phase synthesis. The ligation reaction is generally conducted with two peptide fragments at a high aqueous concentration to increase the reaction rate; however, this often causes unpredictable aggregation and precipitation of starting or resulting peptides due to their hydrophobicities. Here, we have developed a novel peptide ligation strategy ha

Live-cell RNA imaging at specific intracellular locations is technically limited because of the diffusive nature of small oligonucleotide probes. The bulky fluorescent light-up probes that possess streptavidin or gold nanoparticles at the end of oligonucleotides were designed and synthesized. The bulky probes allowed nucleus- and cytoplasm-selective monitoring of endogenous mRNAs through nuclear and cytoplasmic microinjection, respectively. Simultaneous use of bulky and unbulky probes conjugated

Biologically produced protein drugs are generally susceptible to degradation by proteases and often exhibit immunogenicity. To address this issue, mirror-image peptide/protein binders consisting of D-amino acids have been developed so far through the mirror-image phage display technique. Here, we develop a mirror-image protein binder derived from a monobody, one of the promising protein scaffolds, utilizing two notable technologies: chemical protein synthesis and TRAP display, an improved versio