Publications by authors named "Philip Callow"

Article Synopsis
  • The text indicates that there is a correction to an article referenced by the DOI: 10.1371/journal.pone.0035263.
  • This correction likely addresses errors or inaccuracies in the original publication.
  • Such corrections are common in academic publishing to ensure the integrity and accuracy of research findings.
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Article Synopsis
  • The article DOI: 10.1371/journal.pone.0035263 has been revised or updated to correct inaccuracies or errors present in the original publication.
  • The corrections aim to enhance the reliability and clarity of the research findings discussed in that article.
  • Readers are encouraged to refer to the updated version for the most accurate information on the study's conclusions and data.
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The ParB protein, KorB, from the RK2 plasmid is required for DNA partitioning and transcriptional repression. It acts co-operatively with other proteins, including the repressor KorA. Like many multifunctional proteins, KorB contains regions of intrinsically disordered structure, existing in a large ensemble of interconverting conformations.

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Small-angle neutron scattering (SANS) with contrast variation was used to obtain the low-resolution structure of nascent HDL (nHDL) reconstituted with dimyristoyl phosphatidylcholine (DMPC) in the absence and presence of cholesterol, [apoA1:DMPC (1:80, mol:mol) and apoA1:DMPC:cholesterol (1:86:9, mol:mol:mol)]. The overall shape of both particles is discoidal with the low-resolution structure of apoA1 visualized as an open, contorted, and out of plane conformation with three arms in nascent HDL/dimyristoyl phosphatidylcholine without cholesterol (nHDL(DMPC)) and two arms in nascent HDL/dimyristoyl phosphatidylcholine with cholesterol (nHDL(DMPC+Chol)). The low-resolution shape of the lipid phase in both nHDL(DMPC) and nHDL(DMPC+Chol) were oblate ellipsoids, and fit well within their respective protein shapes.

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DNA transposases facilitate genome rearrangements by moving DNA transposons around and between genomes by a cut-and-paste mechanism. DNA transposition proceeds in an ordered series of nucleoprotein complexes that coordinate pairing and cleavage of the transposon ends and integration of the cleaved ends at a new genomic site. Transposition is initiated by transposase recognition of the inverted repeat sequences marking each transposon end.

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Article Synopsis
  • * Syntaxin1a, a neuronal protein, can interact with Munc18-1 both with and without its N-peptide, while Syntaxin4 from adipose tissue requires the N-peptide for interaction with Munc18c.
  • * The study reveals that the Munc18-1:Syntaxin1a complex can exist in two functional states (closed and open), influenced by the presence of the N-peptide, while Munc18c:Syntaxin4 is limited to only the open state.
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  • Type I restriction-modification (RM) systems consist of two main enzymes, the methyltransferase and the restriction endonuclease, that work together to modify and cleave DNA.
  • The study focuses on EcoR124I, an engineered RM system that recognizes a specific DNA sequence and evaluates its endonuclease activity in vitro, as well as how the subunits of the enzyme come together.
  • Using techniques like small-angle neutron scattering, researchers create a structural model of the endonuclease and find that the physical connection between parts of the specificity subunit is not necessary for the enzyme's assembly or function, providing insights into the evolution of these enzymes.
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  • Type I DNA restriction/modification enzymes are crucial molecular machines in most bacteria, playing a key role in genetic engineering by managing the uptake of foreign DNA while modifying host DNA for protection.
  • These enzymes, like EcoKI and EcoR124I, undergo significant structural changes during function, transitioning from an open to a compact form when they bind DNA.
  • The research reveals these enzymes' structures and provides insights into the evolutionary connection between Type I and Type II restriction/modification enzymes through advanced imaging and molecular modeling techniques.
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The structure of cellulose microfibrils in wood is not known in detail, despite the abundance of cellulose in woody biomass and its importance for biology, energy, and engineering. The structure of the microfibrils of spruce wood cellulose was investigated using a range of spectroscopic methods coupled to small-angle neutron and wide-angle X-ray scattering. The scattering data were consistent with 24-chain microfibrils and favored a "rectangular" model with both hydrophobic and hydrophilic surfaces exposed.

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Crucial to glucose homoeostasis in humans, the hPDC (human pyruvate dehydrogenase complex) is a massive molecular machine comprising multiple copies of three distinct enzymes (E1-E3) and an accessory subunit, E3BP (E3-binding protein). Its icosahedral E2/E3BP 60-meric 'core' provides the central structural and mechanistic framework ensuring favourable E1 and E3 positioning and enzyme co-operativity. Current core models indicate either a 48E2+12E3BP or a 40E2+20E3BP subunit composition.

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DivIB(FtsQ), FtsL, and DivIC(FtsB) are enigmatic membrane proteins that are central to the process of bacterial cell division. DivIB(FtsQ) is dispensable in specific conditions in some species, and appears to be absent in other bacterial species. The presence of FtsL and DivIC(FtsB) appears to be conserved despite very low sequence conservation.

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Article Synopsis
  • - Type I restriction-modification (RM) systems consist of three subunits, with HsdS recognizing specific DNA sequences, HsdM methylating adenosine residues, and HsdR translocating and cleaving unmethylated DNA, although the exact mechanism of HsdR remains unclear due to a lack of structural data.
  • - The research identified an error in the gene sequence for the HsdR subunit of EcoR124I, which affected the stop codon position and the last 17 amino acids of the protein, leading to improved purification strategies for HsdR for further analysis.
  • - Using analytical ultracentrifugation and small-angle neutron scattering, the study established that HsdR
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