Electrostatic interactions between

Electrostatic interactions between the positively and negatively
charged amino acids in proteins play an important role in macromolecular stability,
binding, and recognition. Numerous amino acids in proteins are ionizable and may
exist in negatively (e.g., Glu, Asp, Cys, Tyr) or positively (e.g., Arg, Lys, His, Orn)
charged form dependent on pH and their pKas. In this work, isothermal titration
calorimetry was used to determine the average standard values of thermodynamic
parameters (the Gibbs free energy, enthalpy, entropy, and the heat capacity) of
interaction between the positively charged amino acid homopolymers (polyarginine,
polylysine, and polyornithine) and the negatively charged homopolymers
(polyaspartic and polyglutamic acids). These values are of potential use in the
computational models of interacting proteins and other biological macromolecules.
The study showed that oppositely charged poly(amino acid)s bound each other
with the stoichiometry of one positive to one negative charge. Arginine bound to
the negatively charged amino acids with exothermic enthalpy and higher affinity
than lysine. This result also suggests that positive charges in proteins should not be considered entirely equivalent if carried by
lysine or arginine. The difference in binding energy of arginine and lysine association with the negatively charged amino acids was
attributed to the enthalpy of the second ionic hydrogen bond formation between the guanidine and carboxylic groups. Despite
the favorable enthalpic contribution, all such ion pair formation reactions were largely entropy-driven. Consistent with previously
observed ionic interactions, the positive heat capacity was always observed during the amino acid ion pair formation.

ผลลัพธ์ (อังกฤษ) 2:

Electrostatic interactions between the Positively and negatively
charged amino acids in Proteins Play an important role in macromolecular stability,
binding, and Recognition. Proteins are amino acids in numerous Ionizable and May
exist in negatively (eg, Glu, Asp, Cys, Tyr) or Positively (eg, Arg, Lys, His, Orn)
charged form dependent on pH and their PKas. In this Work, isothermal Titration
calorimetry was used to Determine the average standard values ​​of thermodynamic
Parameters (the Gibbs free Energy, enthalpy, entropy, and the heat capacity) of
Interaction between the Positively charged amino acid homopolymers (Polyarginine,
polylysine, and Polyornithine). and the negatively charged homopolymers
(Polyaspartic and Polyglutamic acids). These values ​​are of potential use in the
Computational models of interacting Proteins and Other Biological macromolecules.
The Study Showed that oppositely charged Poly (amino acid) s Other bound each
with the stoichiometry of one positive to one negative charge. Arginine bound to
the negatively charged amino acids with a higher exothermic enthalpy and FFI nity
than lysine. Result also suggests that this should not be considered positive charges in Proteins Equivalent entirely if carried by
lysine or arginine. The FF di arginine and lysine of Energy Erence in binding negatively charged amino acids association with the was
attributed to the enthalpy of the Second Ionic Bond Formation between the guanidine hydrogen and carboxylic groups. Despite
the favorable contribution Enthalpic, all such ion pair Formation reactions were largely entropy-driven. Consistent with previously
observed Ionic interactions, the positive heat capacity was observed during the amino acid ion pair always Formation.