Nanopores have been studied as a unique DNA sequencing technology that can quickly read long stretched DNA sequences. A DNA molecule could pass through a nanopore in a speed of microsecond per base and even faster. Wi...Nanopores have been studied as a unique DNA sequencing technology that can quickly read long stretched DNA sequences. A DNA molecule could pass through a nanopore in a speed of microsecond per base and even faster. With this speed, a human genome can potentially be sequenced by one nanopore in 〈1 h. In contrast to next- generation DNA sequencing （NGS）, the nanopore sequencing is enzyme free without need of sample amplification due to its single-molecule nature. The nanopore sequencing has been envisioned as a new generation of DNA sequencing technology in the post-NGS era. This progress focuses on status quo of the nanopore DNA sequencing and discusses the opportunities and challenges in this rapidly growing field.展开更多
Understanding the mechanisms underlying the assembly of nucleobases is a great challenge. The ability to deeply understand how nucleobases interact with themselves as well as with other molecules will allow us to gain...Understanding the mechanisms underlying the assembly of nucleobases is a great challenge. The ability to deeply understand how nucleobases interact with themselves as well as with other molecules will allow us to gain valuable insights into how we might be able to harness these interesting biological molecules to construct complex nanostructures and materials. Uracil and thymine derivatives have been reported for use in biological applications and in self-assembling triple hydrogen bonded systems. Either uracil or thymine possesses three binding sites （Site 1, Site 2, and Site 3） that can induce strong directional N-H...O=C hydrogen bonding interaction. In this paper, theoretical calculations are carded out on the structural features and binding energies of hydrogen-bonded dimers and trimers formed by uracil and thymine bases. We find that the hydrogen bonds formed through Site 1 are the strongest, those formed through Site 3 are next, while those formed through Site 2 are the weakest. The atoms in molecules analysis show that the electron densities at the bond critical points and the corresponding Laplacians have greater values for those hydrogen bonds formed through Site 1 than through Site 2. All these results indicate that a uracil （or thymine） would interact with another uracil or thymine most likely through Site 1 and least likely through Site 2. We also find that a simple summation rule roughly exists for the binding energies in these dimers and trimers.展开更多
In our synthetic studies toward huperzine A, a diastereoselective α＇-alkylation of the α-amido-γ-methyl hexenone 4 was real- ized through a dianion intermediate which significantly enhanced the reactivity. Under t...In our synthetic studies toward huperzine A, a diastereoselective α＇-alkylation of the α-amido-γ-methyl hexenone 4 was real- ized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular T-arylation of 3 was observed, which generated 18 with bicyclo[3.3, l]nonane framework in satisfactory yield.展开更多
A peptide nucleic acid （PNA）-peptide conjugated molecule, T＇3（AKAE）2, was designed to have both a PNA segment for oligo- nucleotide binding and an ionic self-complementary peptide sequence for self-association. T...A peptide nucleic acid （PNA）-peptide conjugated molecule, T＇3（AKAE）2, was designed to have both a PNA segment for oligo- nucleotide binding and an ionic self-complementary peptide sequence for self-association. T＇3（AKAE）2 could co-assemble with oligoadenines （d（A）x） to form virus-like supramolecular structures whose morphology showed dependence on the chain length and rigidity of the d（A）x molecules. Smaller nanospheres with diameters of 13.0±2.0 nm were produced in the case of d（A）6. Wormlike aggregates with lengths of 20-50 nm and diameters of 15.0±2.5 nm were found in the cases of d（A）12, d（A）ls, d（A）24 and d（A）30. And larger spherical aggregates with diameters of 18±5 nm came into presence in the cases of d（A）36 and d（A）42＋. These nanostructures were suggested to be formed under a cooperative effect of base pair recognition and peptidic association. The study provides insights into the programmed assembly of a multi-components system as well as control of the size and shade of the co-assembled structures, which is of great significance in develouing gene/drug deliverv systems.展开更多
基金supported by the National Natural Science Foundation of China (21372183)the Hubei Province Natural Science Foundation (2013CFB328)+1 种基金the Key Laboratory of Analytical Chemistry for Biology and Medicine (Wuhan University), Ministry of Education (ACBM2014001)the Start-Up-Fund grant provided by Wuhan University of Science and Technology
文摘Nanopores have been studied as a unique DNA sequencing technology that can quickly read long stretched DNA sequences. A DNA molecule could pass through a nanopore in a speed of microsecond per base and even faster. With this speed, a human genome can potentially be sequenced by one nanopore in 〈1 h. In contrast to next- generation DNA sequencing （NGS）, the nanopore sequencing is enzyme free without need of sample amplification due to its single-molecule nature. The nanopore sequencing has been envisioned as a new generation of DNA sequencing technology in the post-NGS era. This progress focuses on status quo of the nanopore DNA sequencing and discusses the opportunities and challenges in this rapidly growing field.
基金supported by the National Natural Science Foundation of China (20973088)the Educational Department of Liaoning Province (2007T091, 2008T106)
文摘Understanding the mechanisms underlying the assembly of nucleobases is a great challenge. The ability to deeply understand how nucleobases interact with themselves as well as with other molecules will allow us to gain valuable insights into how we might be able to harness these interesting biological molecules to construct complex nanostructures and materials. Uracil and thymine derivatives have been reported for use in biological applications and in self-assembling triple hydrogen bonded systems. Either uracil or thymine possesses three binding sites （Site 1, Site 2, and Site 3） that can induce strong directional N-H...O=C hydrogen bonding interaction. In this paper, theoretical calculations are carded out on the structural features and binding energies of hydrogen-bonded dimers and trimers formed by uracil and thymine bases. We find that the hydrogen bonds formed through Site 1 are the strongest, those formed through Site 3 are next, while those formed through Site 2 are the weakest. The atoms in molecules analysis show that the electron densities at the bond critical points and the corresponding Laplacians have greater values for those hydrogen bonds formed through Site 1 than through Site 2. All these results indicate that a uracil （or thymine） would interact with another uracil or thymine most likely through Site 1 and least likely through Site 2. We also find that a simple summation rule roughly exists for the binding energies in these dimers and trimers.
基金supported by the National Natural Science Foundation of China (20902101 & 21172246)National Basic Research Program of China (973 Program) (2010CB833206)
文摘In our synthetic studies toward huperzine A, a diastereoselective α＇-alkylation of the α-amido-γ-methyl hexenone 4 was real- ized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular T-arylation of 3 was observed, which generated 18 with bicyclo[3.3, l]nonane framework in satisfactory yield.
基金the National Natural Science Foundation of China (21473255, 21003160)the Fundamental Research Funds for the Central Universities (14CX05040A, 15CX05017A)
文摘A peptide nucleic acid （PNA）-peptide conjugated molecule, T＇3（AKAE）2, was designed to have both a PNA segment for oligo- nucleotide binding and an ionic self-complementary peptide sequence for self-association. T＇3（AKAE）2 could co-assemble with oligoadenines （d（A）x） to form virus-like supramolecular structures whose morphology showed dependence on the chain length and rigidity of the d（A）x molecules. Smaller nanospheres with diameters of 13.0±2.0 nm were produced in the case of d（A）6. Wormlike aggregates with lengths of 20-50 nm and diameters of 15.0±2.5 nm were found in the cases of d（A）12, d（A）ls, d（A）24 and d（A）30. And larger spherical aggregates with diameters of 18±5 nm came into presence in the cases of d（A）36 and d（A）42＋. These nanostructures were suggested to be formed under a cooperative effect of base pair recognition and peptidic association. The study provides insights into the programmed assembly of a multi-components system as well as control of the size and shade of the co-assembled structures, which is of great significance in develouing gene/drug deliverv systems.
