Investigation of the molecular chaperone DnaJ by analytical ultracentrifugation

Over recent years the binding ability of the molecular chaperone cpn60 (GroEL14) and its co-chaperone cpn10 (GroES7) has been reported to occur under an assortment of specific conditions from the use of non-hydrolysable ATP analogues (namely adenosine 5′-[γ-thio]triphosphate) to requiring hydrolysable ATP for any interaction to occur. We have investigated this further using the molecular hydrodynamic methods (hydrodynamic bead modelling, sedimentation-velocity analytical ultracentrifugation and dynamic light-scattering), allowing the process to be followed under physiologically relevant dilute solution conditions, combined with absorption spectrophotometry to determine GroES7—GroEL14 interaction through the rate inhibition of the cpn60's ATPase activity by GroES7. The results found here indicate that the presence of hydrolysable ATP is required to facilitate correct GroES7 interaction with GroEL14 in solution.

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The Nature of Rapidly Extracted Phycocyanin from the Blue-Green Alga Plectonema Boryanum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065870 ◽

1971 ◽

Vol 29 ◽

pp. 366-367

Author(s):

M. Kessel ◽

R. MacColl

Keyword(s):

Self Assembly ◽

Analytical Ultracentrifugation ◽

Uranyl Acetate ◽

The Self ◽

Major Protein ◽

Subunit Structure ◽

Blue Green Alga ◽

Thin Sections ◽

Blue Green Algae ◽

Cacodylate Buffer

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.

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Molecular chaperone

AccessScience ◽

10.1036/1097-8542.801470 ◽

2015 ◽

Keyword(s):

Molecular Chaperone

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Study of an influence of the intersubunit disulphide bond on the structural properties of a molecular chaperone, murine small heat shock protein HSP25

Immunology Letters ◽

10.1016/s0165-2478(97)88374-5 ◽

1997 ◽

Vol 56 (1-3) ◽

pp. 380

Author(s):

A Zavialov

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Structural Properties ◽

Molecular Chaperone ◽

Small Heat Shock Protein ◽

Disulphide Bond

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Bovine Platelet Proteins II. Purification of Platelet Fibrinogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653556 ◽

1969 ◽

Vol 21 (03) ◽

pp. 419-427 ◽

Cited By ~ 5

Author(s):

N. O Solum ◽

S Łopaciuk

Keyword(s):

Analytical Ultracentrifugation ◽

Insoluble Fraction ◽

Disc Electrophoresis ◽

Plasma Fibrinogen ◽

Starch Gel Electrophoresis ◽

Freezing And Thawing ◽

Insoluble Material ◽

High Resolution Power ◽

Starch Gel ◽

Platelet Proteins

Summary1. Platelet fibrinogen has been purified from washed bovine platelets. The procedure was based on the methods for purification of plasma fibrinogen by fractionated precipitations and extractions with ethanol and glycine below 0°, and precipitation of proteins by dimethylformamide at 0°.2. The platelet extract obtained by freezing and thawing of the cells, freed from insoluble material by centrifugation at 23,000 x g for 30 min, contained 0.22 ±0.003mg fibrinogen per 109 platelets. Total protein of this fraction was 0.77 ±0.08 mg per 109 platelets whereas that of the insoluble fraction was 0.79 ±0.09 mg per 109 platelets.3. The most purified platelet fibrinogen fraction contained 91-98% of the protein in a thrombin-clottable state. The yield was approx. 20%. It showed homogeneity in analytical ultracentrifugation, in immunoelectrophoresis using an antiserum produced by immunization of rabbits against platelet extract, and in starch gel electrophoresis using a discontinuous system of Tris HCl and borate buffers offering a high resolution power towards the platelet proteins. Polyacrylamide disc electrophoresis revealed two to three faint lines behind the main fibrinogen line. At least one such line was also observed with purified plasma fibrinogen.

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The HSP70 Molecular Chaperone Machines

10.3389/978-2-88945-125-8 ◽

2017 ◽

Cited By ~ 1

Keyword(s):

Molecular Chaperone

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A Cross-Method Comparison of Sub-10 nm Nanoparticle Size Distribution

10.26434/chemrxiv.9891992.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Ye Yang ◽

Suiyang Liao ◽

Zhi Luo ◽

Runzhang Qi ◽

Niamh Mac Fhionnlaoich ◽

...

Keyword(s):

Size Distribution ◽

Analytical Ultracentrifugation ◽

Statistical Significance ◽

Method Comparison ◽

Size Determination ◽

Size Dependent ◽

X Ray Scattering ◽

Transmission Electron ◽

Gold Nps ◽

Reliable Representation

Accurate nanoparticle (NP) size determination is essential across research domains, with many functions in nanoscience and biomedical research being size-dependent. Although transmission electron microscopy (TEM) is capable of resolving a single NP down to the sub-nm scale, the reliable representation of entire populations is plagued by challenges in providing statistical significance, predominantly due to limited sample counts, suboptimal preparation procedures and operator bias during image acquisition and analysis. Meanwhile alternative techniques exist, but reliable implementation requires a detailed understanding of appendant limitations. Herein, conventional TEM is compared to the size determination of sub-10 nm gold NPs in solution by small-angle X-ray scattering and analytical ultracentrifugation. Form-free Monte Carlo fitting of scattering profiles offers access to a direct representation of the core size distribution while ultracentrifugation sedimentation velocity analysis provides information of the hydrodynamic size distribution. We report a comparison of these three methods in determining the size of quasi-monodisperse, polydisperse and bimodal gold nanoparticles of 2 – 7 nm and discuss advantages and limitations of each technique.

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