scholarly journals Nucleic Acid Helix Stability: Effects of Salt Concentration, Cation Valence and Size, and Chain Length

2006 ◽  
Vol 90 (4) ◽  
pp. 1175-1190 ◽  
Author(s):  
Zhi-Jie Tan ◽  
Shi-Jie Chen
1980 ◽  
Vol 191 (3) ◽  
pp. 769-776 ◽  
Author(s):  
P E Bock ◽  
M Luscombe ◽  
S E Marshall ◽  
D S Pepper ◽  
J J Holbrook

The anisotropy of the fluorescence of dansyl (5-dimethylaminonaphthalene-1- sulphonyl) groups covalently attached to human platelet factor 4 was used to detect the macromolecular compounds formed when the factor was mixed with heparin. At low heparin/protein ratios a very-high-molecular-weight compound (1) was formed that dissociated to give a smaller compound (2) when excess heparin was added. 2. A large complex was also detected as a precipitate that formed at high protein concentrations in chloride buffer. It contained 15.7% (w/w) polysaccharide, equivalent to four or five heparin tetrasaccharide units per protein tetramer. In this complex, more than one molecule of protein binds to each heparin molecule of molecular weight greater than about 6 × 10(3).3. The stability of these complexes varied with pH, salt concentration and the chain length of the heparin. The limit complexes found in excess of the larger heparins consisted of only one heparin molecule per protein tetramer, and the failure to observe complexes with four heparin molecules/protein tetramer is discussed.


2005 ◽  
Vol 19 (8) ◽  
pp. 606-616 ◽  
Author(s):  
A. C. Dias-Cabral ◽  
A. S. Ferreira ◽  
J. Phillips ◽  
J. A. Queiroz ◽  
N. G. Pinto

1946 ◽  
Vol 30 (2) ◽  
pp. 101-116 ◽  
Author(s):  
A. W. Pollister ◽  
A. E. Mirsky

The nucleoprotamine of trout sperm can be extracted completely with 1 M sodium chloride. On reducing the salt concentration to 0.14 M, physiological saline, the nucleoprotamine precipitates in long, fibrous strands. When the nucleoprotamine, dissolved in M NaCl, is dialyzed all the protamine diffuses through the membrane leaving behind highly polymerized, protein-free desoxyribose nucleic acid. The nucleoprotamine constitutes 91 per cent of the lipid-free mass of the sperm nucleus. While nucleoprotamine is being extracted by M NaCl a stage is reached at which the sperm chromosomes are clearly visible.


2021 ◽  
Author(s):  
Reece W. Lewis ◽  
Benjamin Klemm ◽  
Mariano Macchione ◽  
Rienk Eelkema

Triggered coacervate phase (de)stabilisation in complex coacervate core micelles (C3Ms) has traditionally been limited to changes in pH and salt concentration, limiting options in responsive C3M material design. To expand this toolbox, we have developed C3Ms, that, at constant physiological pH, assemble and disassemble by coupling to a chemical reaction network (CRN) driven by the conversion of electron deficient allyl acetates and thiol or amine nucleophiles. This CRN produces transient quaternization of tertiary amine-functionalised block copolymers, which can then form the complex coacervate phase. We demonstrate triggered C3M assembly using two different allyl acetates, resulting in dramatically different assembly rates from hours to days. These are applied in various combinations with selected nucleophiles, demonstrating sequential signal induced C3M formation and deformation, as well as transient non-equilibrium (de)formation. We expect that timed and signal-responsive control over coacervate phase formation at physiological pH will find application in nucleic acid delivery, nano reactors and protocell research.


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