Isolation and Characterization of Lipid-Protein Complexes Present in Commercial Albumin Preparations

Abstract After lysis of Pseudomonas testosteroni with lysozyme and non-ionic detergents different DNA-protein complexes can be separated in 5 -25% (w/v) neutral sucrose gradient. The protein to DNA ratio of these complexes varies between 0.5-4.5 to 1, whereby the faster sedimenting forms contain more protein than the slower sedimenting ones. Different initial rates of DNase digestion may indicate various degrees of DNA packing in these complexes. The chromosomal complexes of Pseudomonas testosteroni are relatively stable towards pronase. Treatment with RNase or sodium dodecylsulphate is accompanied by a dramatic increase in viscosity and decrease in relative density. It suggests that DNA in these complexes is maintained in its supercoiled form by RNA molecule (s) in a similar way as in isolated chromosome of E. coli.

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Isolation and characterization of the pigment-protein complexes of Rhodopseudomonas sphaeroides by lithium dodecyl sulfate/polyacrylamide gel electrophoresis.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.77.1.87 ◽

1980 ◽

Vol 77 (1) ◽

pp. 87-91 ◽

Cited By ~ 104

Author(s):

R. M. Broglie ◽

C. N. Hunter ◽

P. Delepelaire ◽

R. A. Niederman ◽

N. H. Chua ◽

...

Keyword(s):

Gel Electrophoresis ◽

Protein Complexes ◽

Polyacrylamide Gel Electrophoresis ◽

Polyacrylamide Gel ◽

Rhodopseudomonas Sphaeroides ◽

Isolation And Characterization ◽

Lithium Dodecyl Sulfate ◽

Dodecyl Sulfate ◽

Pigment Protein Complexes

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Isolation and Characterization of HRT1 Using a Genetic Screen for Mutants Unable to Degrade Gic2p in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/155.3.1033 ◽

2000 ◽

Vol 155 (3) ◽

pp. 1033-1044

Author(s):

Marc Blondel ◽

Jean-Marc Galan ◽

Matthias Peter

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Protein Complexes ◽

Ring Finger ◽

Genetic Screen ◽

Single Mutation ◽

Dependent Manner ◽

E3 Ligases ◽

Isolation And Characterization

Abstract Skp1p-cullin-F-box (SCF) protein complexes are ubiquitin ligases required for degradation of many regulatory proteins involved in cell cycle progression, morphogenesis, and signal transduction. Using a genetic screen, we have isolated a novel allele of the HRT1/RBX1 gene in budding yeast (hrt1-C81Y). hrt1-C81Y mutant cells exhibited an aberrant morphology but were viable at all temperatures. The cells displayed multiple genetic interactions with mutations in known SCF components and were defective for the degradation of several SCF targets including Gic2p, Far1p, Sic1p, and Cln2p. In addition, they also failed to degrade the F-box proteins Grr1p, Cdc4p, and Met30p. Wild-type Hrt1p but not Hrt1p-C81Y was able to bind multiple F-box proteins in an F-box-dependent manner. Hrt1p-C81Y harbors a single mutation in its ring-finger domain, which is conserved in subunits of distinct E3 ligases. Finally, Hrt1p was localized in both nucleus and cytoplasm and despite a short half-life was expressed constitutively throughout the cell cycle. Taken together, these results suggest that Hrt1p is a core subunit of multiple SCF complexes.

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