10 research outputs found
Crystal Structure Analysis and the Identification of Distinctive Functional Regions of the Protein Elicitor Mohrip2
The protein elicitor MoHrip2, which was extracted from Magnaporthe oryzae as an exocrine protein, triggers the tobacco immune system and enhances blast resistance in rice. However, the detailed mechanisms by which MoHrip2 acts as an elicitor remain unclear. Here, we investigated the structure of MoHrip2 to elucidate its functions based on molecular structure. The 3-dimensional structure of MoHrip2 was obtained. Overall, the crystal structure formed a β-barrel structure and showed high similarity to the pathogenesis-related (PR) thaumatin superfamily protein thaumatin-like xylanase inhibitor (TL-XI). To investigate the functional regions responsible for MoHrip2 elicitor activities, the full length and 8 truncated proteins were expressed in Escherichia coli and were evaluated for elicitor activity in tobacco. Biological function analysis showed that MoHrip2 triggered the defense system against Botrytis cinerea in tobacco. Moreover, only MoHrip2M14 and other fragments containing the 14 amino acids residues in the middle region of the protein showed the elicitor activity of inducing a hypersensitive response and resistance related pathways, which were similar to that of full-length MoHrip2. These results revealed that the central 14 amino acid residues were essential for anti-pathogenic activity
Two human monoclonal SARS-CoV-2 antibodies that maintain neutralizing potency against the SARS-CoV-2 Omicron BA.1 and BA.2 variants
Monolayer MoS2-Based Flexible and Highly Sensitive Pressure Sensor with Wide Sensing Range
Flexible pressure sensors play an important role in flexible robotics, human-machine interaction (HMI), and human physiological information. However, most of the reported flexible pressure sensors suffer from a highly nonlinear response and a significant decrease in sensitivity at high pressures. Herein, we propose a flexible novel iontronic pressure sensor based on monolayer molybdenum disulfide (MoS2). Based on the unique structure and the excellent mechanical properties as well as the large intercalation capacitance of MoS2, the prepared sensor holds an ultra-high sensitivity (Smax = 89.75 kPa−1) and a wide sensing range (722.2 kPa). Further, the response time and relaxation time of the flexible sensor are only 3 ms, respectively, indicating that the device can respond to external pressure rapidly. In addition, it shows long-term cycling stability (over 5000 cycles with almost no degradation) at a high pressure of 138.9 kPa. Finally, it is demonstrated that the sensor can be used in physiological information monitoring and flexible robotics. It is anticipated that our prepared sensor provide a reliable approach to advance the theory and practicality of the flexible sensor electronics
Highly Selective Off–On Fluorescent Probe for Imaging Thioredoxin Reductase in Living Cells
The
first fluorescent probe for mammalian thioredoxin reductase
(TrxR), TRFS-green, was designed, synthesized, and fully evaluated.
The probe features a 1,2-dithiolane scaffold with a quenched naphthalimide
fluorophore. TRFS-green displays a green fluorescence off–on
change induced by the TrxR-mediated disulfide cleavage and subsequent
intramolecular cyclization to liberate the masked naphthalimide fluorophore.
It was demonstrated in vitro that TRFS-green manifests high selectivity
toward TrxR over other related enzymes and various small molecule
thiols as well as biological reducing molecules. HPLC analyses indicated
that TRFS-green was exclusively converted to naphthalimide catalyzed
by TrxR. The ability in triggering on the fluorescence signal by cellular
protein extracts correlates well with the endogenous TrxR activity
in different cells. Furthermore, inhibition of TrxR by 2,4-dinitrochlorobenzene
or depletion of TrxR by immunoprecipitation remarkably decreases the
reduction of TRFS-green by cellular protein extracts. Finally, TRFS-green
was successfully applied in imaging TrxR activity in living cells.
The fluorescence signal of TRFS-green in living cells was inhibited
by pretreating the cells with TrxR inhibitor in a dose-dependent manner,
potentiating the development of living cell-based screening assay
for identifying TrxR inhibitors. We expect the novel fluorescent probe
TRFS-green would facilitate the discovery of TrxR-targeting small
molecules for potential therapeutic agents and provide significant
advances in understanding the physiological/pathophysiological functions
of TrxR in vivo