22 research outputs found
Hydration of the Sulfuric AcidâMethylamine Complex and Implications for Aerosol Formation
The binary H2SO4âH2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0â6. Because it is a strong acidâbase system, H2SO4âNH2CH3 quickly forms a tightly bound HSO4ââNH3CH3+ complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4âNH2CH3 is â21.8 kcal molâ1 compared with â16.8 kcal molâ1 for H2SO4âNH3 and â12.8 kcal molâ1 for H2SO4âH2O. Adding one to two water molecules to the H2SO4âNH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n â„ 3. However, the average number of water molecules around H2SO4âNH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity
Chromatin targeting of the RNF12/RLIM E3 ubiquitin ligase controls transcriptional responses
Protein ubiquitylation regulates key biological processes including transcription. This is exemplified by the E3 ubiquitin ligase RNF12/RLIM, which controls developmental gene expression by ubiquitylating the REX1 transcription factor and is mutated in an X-linked intellectual disability disorder. However, the precise mechanisms by which ubiquitylation drives specific transcriptional responses are not known. Here, we show that RNF12 is recruited to specific genomic locations via a consensus sequence motif, which enables co-localisation with REX1 substrate at gene promoters. Surprisingly, RNF12 chromatin recruitment is achieved via a non-catalytic basic region and comprises a previously unappreciated N-terminal autoinhibitory mechanism. Furthermore, RNF12 chromatin targeting is critical for REX1 ubiquitylation and downstream RNF12-dependent gene regulation. Our results demonstrate a key role for chromatin in regulation of the RNF12-REX1 axis and provide insight into mechanisms by which protein ubiquitylation enables programming of gene expression.</p
Chromatin targeting of the RNF12/RLIM E3 ubiquitin ligase controls transcriptional responses
Protein ubiquitylation regulates key biological processes including transcription. This is exemplified by the E3 ubiquitin ligase RNF12/RLIM, which controls developmental gene expression by ubiquitylating the REX1 transcription factor and is mutated in an X-linked intellectual disability disorder. However, the precise mechanisms by which ubiquitylation drives specific transcriptional responses are not known. Here, we show that RNF12 is recruited to specific genomic locations via a consensus sequence motif, which enables co-localisation with REX1 substrate at gene promoters. Surprisingly, RNF12 chromatin recruitment is achieved via a non-catalytic basic region and comprises a previously unappreciated N-terminal autoinhibitory mechanism. Furthermore, RNF12 chromatin targeting is critical for REX1 ubiquitylation and downstream RNF12-dependent gene regulation. Our results demonstrate a key role for chromatin in regulation of the RNF12-REX1 axis and provide insight into mechanisms by which protein ubiquitylation enables programming of gene expression.</p
Chromatin targeting of the RNF12/RLIM E3 ubiquitin ligase controls transcriptional responses
Protein ubiquitylation regulates key biological processes including transcription. This isexemplified by the E3 ubiquitin ligase RNF12/RLIM, which controls developmental geneexpression by ubiquitylating the REX1 transcription factor and is mutated in an X-linkedintellectual disability disorder. However, the precise mechanisms by which ubiquitylationdrives specific transcriptional responses are not known. Here, we show that RNF12 isrecruited to specific genomic locations via a consensus sequence motif, which enables colocalisationwith REX1 substrate at gene promoters. Surprisingly, RNF12 chromatinrecruitment is achieved via a non-catalytic basic region and comprises a previouslyunappreciated N-terminal autoinhibitory mechanism. Furthermore, RNF12 chromatintargeting is critical for REX1 ubiquitylation and downstream RNF12-dependent generegulation. Our results demonstrate a key role for chromatin in regulation of the RNF12-REX1axis and provide insight into mechanisms by which protein ubiquitylation enablesprogramming of gene expression
Hydration of the Sulfuric Acid-Methylamine Complex and Implications for Aerosol Formation
The binary H2SO4-H2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0-6. Because it is a strong acid-base system, H2SO4-NH2CH3 quickly forms a tightly bound HSO4(-)-NH3CH3(+) complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4-NH2CH3 is -21.8 kcal mol(-1) compared with -16.8 kcal mol(-1) for H2SO4-NH3 and -12.8 kcal mol(-1) for H2SO4-H2O. Adding one to two water molecules to the H2SO4-NH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n â„ 3. However, the average number of water molecules around H2SO4-NH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity
Hydration of the Sulfuric AcidâMethylamine Complex and Implications for Aerosol Formation
The binary H<sub>2</sub>SO<sub>4</sub>âH<sub>2</sub>O nucleation
is one of the most important pathways by which aerosols form in the
atmosphere, and the presence of ternary species like amines increases
aerosol formation rates. In this study, we focus on the hydration
of a ternary system of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>),
methylamine (NH<sub>2</sub>CH<sub>3</sub>), and up to six waters to
evaluate its implications for aerosol formation. By combining molecular
dynamics (MD) sampling with high-level ab initio calculations, we
determine the thermodynamics of forming H<sub>2</sub>SO<sub>4</sub>(NH<sub>2</sub>CH<sub>3</sub>)Â(H<sub>2</sub>O)<sub><i>n</i></sub>, where <i>n</i> = 0â6. Because it is a strong
acidâbase system, H<sub>2</sub>SO<sub>4</sub>âNH<sub>2</sub>CH<sub>3</sub> quickly forms a tightly bound HSO<sub>4</sub><sup>â</sup>âNH<sub>3</sub>CH<sub>3</sub><sup>+</sup> complex that condenses water more readily than H<sub>2</sub>SO<sub>4</sub> alone. The electronic binding energy of H<sub>2</sub>SO<sub>4</sub>âNH<sub>2</sub>CH<sub>3</sub> is â21.8 kcal
mol<sup>â1</sup> compared with â16.8 kcal mol<sup>â1</sup> for H<sub>2</sub>SO<sub>4</sub>âNH<sub>3</sub> and â12.8
kcal mol<sup>â1</sup> for H<sub>2</sub>SO<sub>4</sub>âH<sub>2</sub>O. Adding one to two water molecules to the H<sub>2</sub>SO<sub>4</sub>âNH<sub>2</sub>CH<sub>3</sub> complex is more favorable
than adding to H<sub>2</sub>SO<sub>4</sub> alone, yet there is no
systematic difference for <i>n</i> â„ 3. However,
the average number of water molecules around H<sub>2</sub>SO<sub>4</sub>âNH<sub>2</sub>CH<sub>3</sub> is consistently higher than
that of H<sub>2</sub>SO<sub>4</sub>, and it is fairly independent
of temperature and relative humidity
Hydration of the Sulfuric Acid-Methylamine Complex and Implications for Aerosol Formation
The binary H2SO4âH2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0â6. Because it is a strong acidâbase system, H2SO4âNH2CH3 quickly forms a tightly bound H2SO4âNH3CH3 + complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4âNH2CH3 is â21.8 kcal molâ1 compared with â16.8 kcal molâ1 for H2SO4âNH3 and â12.8 kcal molâ1 for H2SO4âH2O. Adding one to two water molecules to the H2SO4âNH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n â„ 3. However, the average number of water molecules around H2SO4âNH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity
Hydration of the Sulfuric AcidâMethylamine Complex and Implications for Aerosol Formation
NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics
Xenarthransâanteaters, sloths, and armadillosâhave essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data