Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Keywords: PROTEINS ; VELOCITY ; AGGREGATION ; BIOPHARMACEUTICALS ; FLUORESCENCE-DETECTED SEDIMENTATION ; SIZE-EXCLUSION CHROMATOGRAPHY ; FIELD-FLOW FRACTIONATION ; SPINCO ULTRACENTRIFUGE ; BEAD MODELS ; HYDRODYNAMICS
    Abstract: Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 +/- 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of +/- 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies.
    Type of Publication: Journal article published
    PubMed ID: 25997164
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1017
    Keywords: Key words IgE ; FcεRI ; Stoichiometry ; Analytical centrifugation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A soluble fragment of the high-affinity IgE receptor FcεRI α-chain (sFcεRIα) binds to the Fc fragment of IgE (IgE-Fc) as a 1:1 complex. IgE-Fc consists of a dimer of the Cε2, Cε3 and Cε4 domains of the ε-heavy chain of IgE. This region of IgE has been modelled on the crystal structure of the Fc region of IgG1, which exhibits twofold rotational symmetry. This implies that IgE should be divalent with respect to its ligands. X-ray scattering studies reveal however that the twofold rotational symmetry of IgE-Fc is perturbed by a bend in the linker region between the Cε2 and Cε3 domains. The 1:1 stoichiometry could then arise from the conformational asymmetry or from steric occlusion of one of the sites by the overhanging Cε2 domains. To test this hypothesis we have expressed a recombinant ε-chain fragment containing Cε3 and Cε4. This product, Fcε3–4, is secreted from cells as a disulphide linked dimer and binds with higher affinity than either IgE or IgE-Fc to cell surface FcεRI. Titration experiments, together with molecular mass measurements of the Fcε3–4/sFcεRIα complex, reveal that Fcε3–4 binds only a single receptor molecule. This excludes the possibility that steric hindrance by Cε2 accounts for the unexpected stoichiometry.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0022-2836
    Keywords: chromatin compaction ; negative supercoils ; nucleosome core ; positive supercoils
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0040-4020
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2018-01-19
    Description: Accurate chromosome segregation requires the proper assembly of kinetochore proteins. A key step in this process is the recognition of the histone H3 variant CENP-A in the centromeric nucleosome by the kinetochore protein CENP-N. We report cryo–electron microscopy (cryo-EM), biophysical, biochemical, and cell biological studies of the interaction between the CENP-A nucleosome and CENP-N. We show that human CENP-N confers binding specificity through interactions with the L1 loop of CENP-A, stabilized by electrostatic interactions with the nucleosomal DNA. Mutational analyses demonstrate analogous interactions in Xenopus , which are further supported by residue-swapping experiments involving the L1 loop of CENP-A. Our results are consistent with the coevolution of CENP-N and CENP-A and establish the structural basis for recognition of the CENP-A nucleosome to enable kinetochore assembly and centromeric chromatin organization.
    Keywords: Biochemistry, Cell Biology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2011-03-18
    Description: The centromere is a unique chromosomal locus that ensures accurate segregation of chromosomes during cell division by directing the assembly of a multiprotein complex, the kinetochore. The centromere is marked by a conserved variant of conventional histone H3 termed CenH3 or CENP-A (ref. 2). A conserved motif of CenH3, the CATD, defined by loop 1 and helix 2 of the histone fold, is necessary and sufficient for specifying centromere functions of CenH3 (refs 3, 4). The structural basis of this specification is of particular interest. Yeast Scm3 and human HJURP are conserved non-histone proteins that interact physically with the (CenH3-H4)(2) heterotetramer and are required for the deposition of CenH3 at centromeres in vivo. Here we have elucidated the structural basis for recognition of budding yeast (Saccharomyces cerevisiae) CenH3 (called Cse4) by Scm3. We solved the structure of the Cse4-binding domain (CBD) of Scm3 in complex with Cse4 and H4 in a single chain model. An alpha-helix and an irregular loop at the conserved amino terminus and a shorter alpha-helix at the carboxy terminus of Scm3(CBD) wraps around the Cse4-H4 dimer. Four Cse4-specific residues in the N-terminal region of helix 2 are sufficient for specific recognition by conserved and functionally important residues in the N-terminal helix of Scm3 through formation of a hydrophobic cluster. Scm3(CBD) induces major conformational changes and sterically occludes DNA-binding sites in the structure of Cse4 and H4. These findings have implications for the assembly and architecture of the centromeric nucleosome.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077455/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077455/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, Zheng -- Feng, Hanqiao -- Zhou, Bing-Rui -- Ghirlando, Rodolfo -- Hu, Kaifeng -- Zwolak, Adam -- Miller Jenkins, Lisa M -- Xiao, Hua -- Tjandra, Nico -- Wu, Carl -- Bai, Yawen -- Z01 BC010808-01/Intramural NIH HHS/ -- England -- Nature. 2011 Apr 14;472(7342):234-7. doi: 10.1038/nature09854. Epub 2011 Mar 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21412236" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Amino Acid Sequence ; Autoantigens/chemistry/metabolism ; Binding Sites ; Centromere/*chemistry/metabolism ; Chromosomal Proteins, Non-Histone/*chemistry/*metabolism ; Conserved Sequence ; DNA/chemistry/metabolism ; DNA-Binding Proteins/*chemistry/*metabolism ; Histones/chemistry/metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Molecular Chaperones/chemistry/metabolism ; Molecular Sequence Data ; Nuclear Magnetic Resonance, Biomolecular ; Nucleosomes/chemistry/metabolism ; Protein Binding ; Protein Conformation ; *Saccharomyces cerevisiae/cytology/metabolism ; Saccharomyces cerevisiae Proteins/*chemistry/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2011-11-01
    Description: Exchange dynamics between molecules free in solution and bound to the surface of a large supramolecular structure, a polymer, a membrane or solid support are important in many phenomena in biology and materials science. Here we present a novel and generally applicable solution NMR technique, known as dark-state exchange saturation transfer (DEST), to probe such exchange phenomena with atomic resolution. This is illustrated by the exchange reaction between amyloid-beta (Abeta) monomers and polydisperse, NMR-invisible ('dark') protofibrils, a process of significant interest because the accumulation of toxic, aggregated forms of Abeta, from small oligomers to very large assemblies, has been implicated in the aetiology of Alzheimer's disease. The (15)N-DEST experiment imprints with single-residue-resolution dynamic information on the protofibril-bound species in the form of (15)N transverse relaxation rates ((15)N-R(2)) and exchange kinetics between monomers and protofibrils onto the easily observed two-dimensional (1)H-(15)N correlation spectrum of the monomer. The exchanging species on the protofibril surface comprise an ensemble of sparsely populated states where each residue is either tethered to (through other residues) or in direct contact with the surface. The first eight residues exist predominantly in a mobile tethered state, whereas the largely hydrophobic central region and part of the carboxy (C)-terminal hydrophobic region are in direct contact with the protofibril surface for a significant proportion of the time. The C-terminal residues of both Abeta40 and Abeta42 display lower affinity for the protofibril surface, indicating that they are likely to be surface exposed rather than buried as in structures of Abeta fibrils, and might therefore comprise the critical nucleus for fibril formation. The values, however, are significantly larger for the C-terminal residues of Abeta42 than Abeta40, which might explain the former's higher propensity for rapid aggregation and fibril formation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3237923/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3237923/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fawzi, Nicolas L -- Ying, Jinfa -- Ghirlando, Rodolfo -- Torchia, Dennis A -- Clore, G Marius -- Z01 DK029023-18/Intramural NIH HHS/ -- England -- Nature. 2011 Oct 30;480(7376):268-72. doi: 10.1038/nature10577.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22037310" target="_blank"〉PubMed〈/a〉
    Keywords: Alzheimer Disease/metabolism ; Amino Acid Sequence ; Amyloid/*chemistry ; Amyloid beta-Peptides/*chemistry ; Kinetics ; Molecular Sequence Data ; Nuclear Magnetic Resonance, Biomolecular ; Protein Multimerization ; Thermodynamics
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2013-06-01
    Description: Chromosome segregation during mitosis requires assembly of the kinetochore complex at the centromere. Kinetochore assembly depends on specific recognition of the histone variant CENP-A in the centromeric nucleosome by centromere protein C (CENP-C). We have defined the determinants of this recognition mechanism and discovered that CENP-C binds a hydrophobic region in the CENP-A tail and docks onto the acidic patch of histone H2A and H2B. We further found that the more broadly conserved CENP-C motif uses the same mechanism for CENP-A nucleosome recognition. Our findings reveal a conserved mechanism for protein recruitment to centromeres and a histone recognition mode whereby a disordered peptide binds the histone tail through hydrophobic interactions facilitated by nucleosome docking.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3763809/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3763809/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kato, Hidenori -- Jiang, Jiansheng -- Zhou, Bing-Rui -- Rozendaal, Marieke -- Feng, Hanqiao -- Ghirlando, Rodolfo -- Xiao, T Sam -- Straight, Aaron F -- Bai, Yawen -- R01 GM074728/GM/NIGMS NIH HHS/ -- Y1-CO-1020/CO/NCI NIH HHS/ -- Y1-GM-1104/GM/NIGMS NIH HHS/ -- ZIA AI000960-07/Intramural NIH HHS/ -- New York, N.Y. -- Science. 2013 May 31;340(6136):1110-3. doi: 10.1126/science.1235532.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23723239" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Amino Acid Sequence ; Animals ; Autoantigens/metabolism ; Binding Sites ; Centromere/*metabolism ; Chromosomal Proteins, Non-Histone/genetics/*metabolism ; Conserved Sequence ; Drosophila ; Histones/*metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions ; Molecular Sequence Data ; Nucleosomes/*metabolism ; Protein Structure, Secondary
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...