scholarly journals Photocontrol of the Structure and Functions of a Polypeptide Membrane Composed of Poly(L-glutamic acid) Containing Pararosaniline Leucocyanide Groups in the Side Chains

1989 ◽  
Vol 21 (5) ◽  
pp. 369-376 ◽  
Author(s):  
Morimasa Sato ◽  
Takatoshi Kinoshita ◽  
Akira Takizawa ◽  
Yoshiharu Tsujita
Keyword(s):  
Glutamic Acid ◽  
Side Chains ◽  
Structure And Functions

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

scholarly journals Effects of Amino Acid Side Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

2021 ◽  
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α-L-glutamic acid and α-L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is the search of the ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side chain length, chemical structure and their interplay is required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side chain rotation enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

Reversible conformational changes induced by light in poly(L-glutamic acid) with photochromic side chains

1980 ◽  
Vol 102 (18) ◽  
pp. 5913-5915 ◽  
Author(s):  
Osvaldo Pieroni ◽  
Julien L. Houben ◽  
Adriano Fissi ◽  
Paolo Costantino ◽  
Francesco Ciardelli
Keyword(s):  
Glutamic Acid ◽  
Conformational Changes ◽  
Side Chains

Photoinduced conformational transition of polypeptide membrane composed of poly(L-glutamic acid) containing pararosaniline groups in the side chains

1988 ◽  
Vol 21 (12) ◽  
pp. 3419-3424 ◽  
Author(s):  
Morimasa Sato ◽  
Takatoshi Kinoshita ◽  
Akira Takizawa ◽  
Yoshiharu Tsujita
Keyword(s):  
Glutamic Acid ◽  
Conformational Transition ◽  
Side Chains

Sodium versus potassium effects on the glutamic acid side-chains interaction on a heptapeptide

2014 ◽  
Vol 13 (03) ◽  
pp. 1440004 ◽  
Author(s):  
Eliana K. Asciutto ◽  
Timothy Gaborek ◽  
Jeffry D. Madura
Keyword(s):  
Glutamic Acid ◽  
Pure Water ◽  
Three Dimensional ◽  
Side Chains ◽  
Saline Environment ◽  
Polyproline Ii ◽  
Peptide Conformations ◽  
Free Energy Landscapes ◽  
The Stability ◽  
Α Helix

Equilibrium peptide conformations in solution, especially in the presence of salts, has been of interest for several decades. The fundamental interactions that determine the dominant peptide conformations in solution have been experimentally and computationally probed; however, a unified understanding has not yet emerged. In a previous study, we performed metadynamics simulations on the heptapeptide AEAAAEA in Sodium Chloride ( NaCl ) and Potassium Chloride ( KCl ) solutions at concentrations ranging from 0.5–2.0 M. Using a three-dimensional collective variable coordinate system, we computed the free energy landscapes in each saline environment as well as in pure water. We found that the presence of Na + and K + ions induces some changes in the stability of the conformers that define the state space, but does not alter the overall energetics between conformers and does not favor helical conformations. We investigate here, how the presence of salts ( NaCl and KCl ) affects the glutamic–glutamic interaction and its consequences on the stability of each equilibrium conformation. We perform this study through fixed backbone simulations for the most populated conformations identified in our previous work: the α-helix, 310-helix, π-helix, the extended polyproline II (PPII) and 2.51-helix conformations. It was found that for each conformation, there exists stable substates determined by the glutamic acid side-chains distance and orientation, and that Na + and K + cations (de)stabilize preferentially each conformation. It was also found that intramolecular single water mediated hydrogen bonds play a crucial role in the observed (de) stabilization of each equilibrium conformation.

scholarly journals Mutational Analysis of a Conserved Glutamic Acid Required for Self-Catalyzed Cross-Linking of Bacteriophage HK97 Capsids

2008 ◽  
Vol 83 (5) ◽  
pp. 2088-2098 ◽  
Author(s):  
Lindsay E. Dierkes ◽  
Craig L. Peebles ◽  
Brian A. Firek ◽  
Roger W. Hendrix ◽  
Robert L. Duda
Keyword(s):  
Glutamic Acid ◽  
Large Scale ◽  
Mutational Analysis ◽  
Chemical Mechanism ◽  
Proton Acceptor ◽  
Cross Linking ◽  
Side Chains ◽  
Cross Link ◽  
Cross Links ◽  
The Cross

ABSTRACT The capsid of bacteriophage HK97 is stabilized by ∼400 covalent cross-links between subunits which form without any action by external enzymes or cofactors. Cross-linking only occurs in fully assembled particles after large-scale structural changes bring together side chains from three subunits at each cross-linking site. Isopeptide cross-links form between asparagine and lysine side chains on two subunits. The carboxylate of glutamic acid 363 (E363) from a third subunit is found ∼2.4 Å from the isopeptide bond in the partly hydrophobic pocket that contains the cross-link. It was previously reported without supporting data that changing E363 to alanine abolishes cross-linking, suggesting that E363 plays a role in cross-linking. This alanine mutant and six additional substitutions for E363 were fully characterized and the proheads produced by the mutants were tested for their ability to cross-link under a variety of conditions. Aspartic acid and histidine substitutions supported cross-linking to a significant extent, while alanine, asparagine, glutamine, and tyrosine did not, suggesting that residue 363 acts as a proton acceptor during cross-linking. These results support a chemical mechanism, not yet fully tested, that incorporates this suggestion, as well as features of the structure at the cross-link site. The chemically identical isopeptide bonds recently documented in bacterial pili have a strikingly similar chemical geometry at their cross-linking sites, suggesting a common chemical mechanism with the phage protein, but the completely different structures and folds of the two proteins argues that the phage capsid and bacterial pilus proteins have achieved shared cross-linking chemistry by convergent evolution.

scholarly journals Reactions of I,I-Diacetoxyiodobenzene with Proteins: Conversion of Amide Side-Chains to Amines

1981 ◽  
Vol 34 (4) ◽  
pp. 395 ◽  
Author(s):  
Leo A Holt ◽  
Brian Milligan
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Side Reactions ◽  
Side Chains ◽  
Diaminobutyric Acid ◽  
Methyl Cyanide ◽  
Diaminopropionic Acid ◽  
Derivatives Of

Experiments with the N-benzyloxycarbonyl derivatives of asparagine and glutamine as models show that, in unbuffered solutions, I,I-diacetoxyiodobenzene (1) is more effective than the corresponding trifluoroacetoxy derivative (2) for converting the amide side-chains of proteins to amines. Maximum modification of the glutamine residues of insulin and lysozyme occurs within 1-2 h of treatment with 1 in aqueous methyl cyanide at 20�C, but asparagine residues react more slowly. The amide side-chains are converted to the corresponding amines in at least 90 % yield, as shown by analysis of acid hydrolysates for aspartic acid, lX,p-diaminopropionic acid, glutamic acid and lX,y-diaminobutyric acid. Numerous side-reactions also occur, tyrosine, cystine, methionine, arginine, lysine and N-terminal residues all being modified to some extent.

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