scholarly journals Tug of War between Condensate Phases in a Minimal Macromolecular System

2020 ◽  
Vol 142 (19) ◽  
pp. 8848-8861 ◽  
Author(s):  
Archishman Ghosh ◽  
Xiaojia Zhang ◽  
Huan-Xiang Zhou
1961 ◽  
Vol 16 (11) ◽  
pp. 730-739 ◽  
Author(s):  
A. Kleinschmidt. ◽  
D. Lang ◽  
C. Plescher ◽  
W. Hellmann ◽  
J. Haass ◽  
...  

1. Electron micrographs of ultra-thin sections of Staphylococcus aureus and Micrococcus lysodeikticus in Vestopal as embedding medium disclose a multiplicity of DNA containing threads with varying interparticular distances.2. The diameter of these threads is about one tenth of the average optimal section thickness.3. This section thickness inevitably is implicated in the visualization of the internal distances between the threads as well as in some common trends in the DNA pool, a fact that has to be accounted for in the analysis of the macromolecules.4. By spreading lysozyme protoplasts of M. lysodeikticus on a water-air interface in a Langmuir trough and by transferring this surface layer to carbon supported Formvar films, two-dimensional systems can be demonstrated which as a thread of constant width comprise the total DNA content of one microorganism each.5. Such a macromolecular system shows equally shaped, coiled loops in a peripheral zone and many crossings towards the center. Branching of threads never has been observed so far. From this evidence we conlude:a) Intracellular DNA in these bacteria seems to exist in one pool as a “woolen ball” which is centered in the cytoplasm as a more or less dense object.b) This “woolen ball“ embodies the total amount of DNA most probably as one single threadlike unit.6. Partial destruction of the thread system of protoplasts will result upon changing optimal spreading conditions.7. The same kind of destruction is shown upon isolation of the DNA from protoplasts, the length of the threads being an inverse function of the number of precipitation steps showing purification.


1982 ◽  
Vol 205 (3) ◽  
pp. 639-641 ◽  
Author(s):  
J. Michael Creeth ◽  
Stephen E. Harding

A simple check for the presence of heterogeneity in a macromolecular system is proposed, employing comparison of Rayleigh sedimentation-equilibrium patterns for two solutions of the same fringe concentration but differing absolute concentrations. The method is illustrated by application to a bronchial glycoprotein from a cystic-fibrosis patient.


2002 ◽  
Vol 35 (7) ◽  
pp. 2748-2753 ◽  
Author(s):  
Sehoon Kim ◽  
Dong Wook Chang ◽  
Soo Young Park ◽  
Hideki Kawai ◽  
Toshihiko Nagamura

Pramana ◽  
1981 ◽  
Vol 17 (4) ◽  
pp. 361-368 ◽  
Author(s):  
R C Agnihotri ◽  
C Mehrotra ◽  
V D Gupta ◽  
Vandana Srivastava

Author(s):  
M. Boublik ◽  
G.T. Oostergetel ◽  
B. Frankland ◽  
F.P. Ottensmeyer

Visualization of the in situ location of the individual components of any macromolecular system is important for understanding its assembly, interactions, and function. Ribosomes, which are small cellular organelles involved in protein synthesis are high molecular weight nucleoprotein complexes composed only of proteins and RNAs. This “simple” composition of ribosomes enables us topographical studies directed either towards localization of the individual ribosomal protein and RNA molecules or merely to the determination of the distribution of the protein and RNA moieties within the ribosome and its subunits. We have utilized the recent progress in the development of microanalytical electron spectroscopic techniques, electron energy loss spectroscopy (EELS) in particular, and the unique distribution of the phosphorus atoms on the ribosome (the phosphorus atoms are present only in the structural backbone of the rRNA) for the direct tracing of the RNA molecules in situ.


2010 ◽  
Vol 98 (9) ◽  
pp. 1986-1994 ◽  
Author(s):  
Patrick J.B. Edwards ◽  
Motoko Kakubayashi ◽  
Robin Dykstra ◽  
Steven M. Pascal ◽  
Martin A.K. Williams

Author(s):  
Takuya Matsumoto ◽  
Haruka Matsuo ◽  
Saki Sumida ◽  
Yoshiaki Hirano ◽  
Dock-Chil Che ◽  
...  

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Anusmita Sahoo ◽  
Shruti Khare ◽  
Sivasankar Devanarayanan ◽  
Pankaj C. Jain ◽  
Raghavan Varadarajan

Identification of residue-residue contacts from primary sequence can be used to guide protein structure prediction. Using Escherichia coli CcdB as the test case, we describe an experimental method termed saturation-suppressor mutagenesis to acquire residue contact information. In this methodology, for each of five inactive CcdB mutants, exhaustive screens for suppressors were performed. Proximal suppressors were accurately discriminated from distal suppressors based on their phenotypes when present as single mutants. Experimentally identified putative proximal pairs formed spatial constraints to recover >98% of native-like models of CcdB from a decoy dataset. Suppressor methodology was also applied to the integral membrane protein, diacylglycerol kinase A where the structures determined by X-ray crystallography and NMR were significantly different. Suppressor as well as sequence co-variation data clearly point to the X-ray structure being the functional one adopted in vivo. The methodology is applicable to any macromolecular system for which a convenient phenotypic assay exists.


2020 ◽  
Author(s):  
Archishman Ghosh ◽  
Xiaojia Zhang ◽  
Huan-Xiang Zhou

AbstractMembraneless organelles formed via liquid-liquid phase separation (LLPS) contain a multitude of macromolecular species. A few of these species drive LLPS while most serve as regulators. The LLPS of SH35 (S) and PRM5 (P), two oppositely charged protein constructs, was promoted by a polyanion heparin (H) but suppressed by a cationic protein lysozyme (L). Here, using these four components alone, we demonstrate complex phase behaviors associated with membraneless organelles and uncover the underlying physical rules. The S:P, S:L, and P:H binaries form droplets, but the H:L binary forms precipitates, therefore setting off a tug of water between different phases within the S:P:H:L quaternary. We observe dissolution of precipitates upon compositional change, transformation from precipitates to droplet-like condensates over time, and segregation of S:L-rich and P:H-rich foci inside droplet-like condensates. A minimal macromolecular system can thus recapitulate membraneless organelles in essential ways and provide crucial physical understanding.


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