Spectroscopic Signatures of Mode-Dependent Tunnel Splitting in the Iodide–Water Binary Complex

2020 ◽  
Vol 124 (15) ◽  
pp. 2991-3001 ◽  
Author(s):  
Justin J. Talbot ◽  
Nan Yang ◽  
Meng Huang ◽  
Chinh H. Duong ◽  
Anne B. McCoy ◽  
...  
Keyword(s):  
Binary Complex ◽  
Tunnel Splitting ◽  
Spectroscopic Signatures

scholarly journals Linking Bi-Metal Distribution Patterns in Porous Carbon Nitride Fullerene to Its Catalytic Activity toward Gas Adsorption

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1794
Author(s):  
Parisa Nematollahi ◽  
Erik C. Neyts
Keyword(s):  
Catalytic Activity ◽  
Carbon Nitride ◽  
Gas Adsorption ◽  
Distribution Patterns ◽  
Catalyst Design ◽  
Metal Distribution ◽  
Binary Complex ◽  
Metal Atoms ◽  
Metal Composition ◽  
Single Transition

Immobilization of two single transition metal (TM) atoms on a substrate host opens numerous possibilities for catalyst design. If the substrate contains more than one vacancy site, the combination of TMs along with their distribution patterns becomes a design parameter potentially complementary to the substrate itself and the bi-metal composition. By means of DFT calculations, we modeled three dissimilar bi-metal atoms (Ti, Mn, and Cu) doped into the six porphyrin-like cavities of porous C24N24 fullerene, considering different bi-metal distribution patterns for each binary complex, viz. TixCuz@C24N24, TixMny@C24N24, and MnyCuz@C24N24 (with x, y, z = 0–6). We elucidate whether controlling the distribution of bi-metal atoms into the C24N24 cavities can alter their catalytic activity toward CO2, NO2, H2, and N2 gas capture. Interestingly, Ti2Mn4@C24N24 and Ti2Cu4@C24N24 complexes showed the highest activity and selectively toward gas capture. Our findings provide useful information for further design of novel few-atom carbon-nitride-based catalysts.

scholarly journals Domains for protein-protein interactions at the N and C termini of the large subunit of bacteriophage lambda terminase.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 477-484
Author(s):  
W F Wu ◽  
S Christiansen ◽  
M Feiss
Keyword(s):  
Protein Interactions ◽  
Ternary Complex ◽  
Large Subunit ◽  
Small Subunit ◽  
Functional Domain ◽  
Binary Complex ◽  
Protein Protein Interactions ◽  
Related Phage ◽  
Carboxy Terminal ◽  
Lambda Dna

Abstract The large subunit of phage lambda terminase, gpA, the gene product of the phage A gene, interacts with the small subunit, gpNul, to form functional terminase. Terminase binds to lambda DNA at cosB to form a binary complex. The terminase:DNA complex binds a prohead to form a ternary complex. Ternary complex formation involves an interaction of the prohead with gpA. The amino terminus of gpA contains a functional domain for interaction with gpNul, and the carboxy-terminal 38 amino acids of gpA contain a functional domain for prohead binding. This information about the structure of gpA was obtained through the use of hybrid phages resulting from recombination between lambda and the related phage 21. lambda and 21 encode terminases that are analogous in structural organization and have ca. 60% sequence identity. In spite of these similarities, lambda and 21 terminases differ in specificity for DNA binding, subunit assembly, and prohead binding. A lambda-21 hybrid phage produces a terminase in which one of the subunits is chimeric and had recombinant specificities. In the work reported here; a new hybrid, lambda-21 hybrid 67, is characterized. lambda-21 hybrid 67 is the result of a crossover between lambda and 21 in the large subunit genes, such that the DNA from the left chromosome end is from 21, including cosB phi 21, the 1 gene, and the first 48 codons for the 2 gene. The rest of the hybrid 67 chromosome is lambda DNA, including 593 codons of the A gene. The chimeric gp2/A of hybrid 67 binds gp1 to form functional terminase.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Three Pillars of Natural Product Dereplication. Alkaloids from the Bulbs of Urceolina peruviana (C. Presl) J.F. Macbr. as a Preliminary Test Case

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 637
Author(s):  
Mariacaterina Lianza ◽  
Ritchy Leroy ◽  
Carine Machado Rodrigues ◽  
Nicolas Borie ◽  
Charlotte Sayagh ◽  
...  
Keyword(s):  
Natural Product ◽  
Spectroscopic Data ◽  
Preliminary Test ◽  
Rapid Identification ◽  
Molecular Structures ◽  
Data Sources ◽  
Test Case ◽  
The Andes ◽  
Spectroscopic Signatures ◽  
Product Chemistry

The role and importance of the identification of natural products are discussed in the perspective of the study of secondary metabolites. The rapid identification of already reported compounds, or structural dereplication, is recognized as a key element in natural product chemistry. The biological taxonomy of metabolite producing organisms, the knowledge of metabolite molecular structures, and the availability of metabolite spectroscopic signatures are considered as the three pillars of structural dereplication. The role and the construction of databases is illustrated by references to the KNApSAcK, UNPD, CSEARCH, and COCONUT databases, and by the importance of calculated taxonomic and spectroscopic data as substitutes for missing or lost original ones. Two NMR-based tools, the PNMRNP database that derives from UNPD, and KnapsackSearch, a database generator that provides taxonomically focused libraries of compounds, are proposed to the community of natural product chemists. The study of the alkaloids from Urceolina peruviana, a plant from the Andes used in traditional medicine for antibacterial and anticancer actions, has given the opportunity to test different approaches to dereplication, favoring the use of publicly available data sources.

scholarly journals Spectroscopy of a tunable moiré system with a correlated and topological flat band

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaomeng Liu ◽  
Cheng-Li Chiu ◽  
Jong Yeon Lee ◽  
Gelareh Farahi ◽  
Kenji Watanabe ◽  
...  
Keyword(s):  
Band Structure ◽  
Twist Angle ◽  
Bilayer Graphene ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Flat Band ◽  
Correlated Electron ◽  
Partial Filling ◽  
Valley Polarization ◽  
Spectroscopic Signatures

AbstractMoiré superlattices created by the twisted stacking of two-dimensional crystals can host electronic bands with flat energy dispersion in which enhanced interactions promote correlated electron states. The twisted double bilayer graphene (TDBG), where two Bernal bilayer graphene are stacked with a twist angle, is such a moiré system with tunable flat bands. Here, we use gate-tuned scanning tunneling spectroscopy to directly demonstrate the tunability of the band structure of TDBG with an electric field and to show spectroscopic signatures of electronic correlations and topology for its flat band. Our spectroscopic experiments are in agreement with a continuum model of TDBG band structure and reveal signatures of a correlated insulator gap at partial filling of its isolated flat band. The topological properties of this flat band are probed with the application of a magnetic field, which leads to valley polarization and the splitting of Chern bands with a large effective g-factor.

scholarly journals Mechanistic insights into the R-loop formation and cleavage in CRISPR-Cas12i1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo Zhang ◽  
Diyin Luo ◽  
Yu Li ◽  
Vanja Perčulija ◽  
Jing Chen ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dna Cleavage ◽  
Binary Complex ◽  
Loop Formation ◽  
Dna Duplex ◽  
Target Dna ◽  
Before And After ◽  
Dna Strand ◽  
Type V ◽  
Functionally Diverse

AbstractCas12i is a newly identified member of the functionally diverse type V CRISPR-Cas effectors. Although Cas12i has the potential to serve as genome-editing tool, its structural and functional characteristics need to be investigated in more detail before effective application. Here we report the crystal structures of the Cas12i1 R-loop complexes before and after target DNA cleavage to elucidate the mechanisms underlying target DNA duplex unwinding, R-loop formation and cis cleavage. The structure of the R-loop complex after target DNA cleavage also provides information regarding trans cleavage. Besides, we report a crystal structure of the Cas12i1 binary complex interacting with a pseudo target oligonucleotide, which mimics target interrogation. Upon target DNA duplex binding, the Cas12i1 PAM-interacting cleft undergoes a remarkable open-to-closed adjustment. Notably, a zipper motif in the Helical-I domain facilitates unzipping of the target DNA duplex. Formation of the 19-bp crRNA-target DNA strand heteroduplex in the R-loop complexes triggers a conformational rearrangement and unleashes the DNase activity. This study provides valuable insights for developing Cas12i1 into a reliable genome-editing tool.

scholarly journals Spectroscopic signatures of the T to R conformational transition in the insulin hexamer

1989 ◽  
Vol 264 (32) ◽  
pp. 19081-19085 ◽  
Author(s):  
M Roy ◽  
M L Brader ◽  
R W Lee ◽  
N C Kaarsholm ◽  
J F Hansen ◽  
...  
Keyword(s):  
Conformational Transition ◽  
Spectroscopic Signatures
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