Ramachandran plot data were generated for 50 thermophilic and 50 mesophilic proteins The proteins Table B and C in S1 File which were used for the assessment of the salt bridges and other physico-chemical properties, further utilized to generate the Ramachandran plot utilizing the STAN—the STructure ANalysis server Uppsala Software Factory [ 30 ]. This is reported that Cys can be modified and remain as-SH or-S-S- form for the enactment of the redox-switching of some of the protein molecules depending on the intracellular redox status.
And, the de-selection of the destabilizing polar amino acids in thermophilic proteins, as found in the present study has been a natural deliberation. Our points have been strongly justified by Karplus 1996 and Berkholz et al.
Linus Pauling and the planar peptide bond.
The effect of net charge on the solubility, activity, and stability of ribonuclease Sa. View Article Google Scholar 43.
References 1. Understanding biological functions through molecular networks. When the average charge in mesophiles is found to be a positive value at neutral pH , the same is found to be negative in thermophiles Fig 3. The pI, a determinant of protein solubility and stability is of the great practical importance in some disease condition, i.
This figure demonstrates the possible fates of a polypeptide having a significant hydrophilic and hydrophobic residues combination. PLoS One.
Arrigo AP. Electrostatic contribution of surface charge residues to the stability of a thermophilic protein: These findings are suggested to have more evolutionary concern than only physical thermo-stabilization in protein molecules [ 79 ]. The results from Fig 1 suggest the higher rate of occurrence of Ala in a number of thermophilic proteins, but lower rate was occurring in more mesophilic proteins.
The higher level of phospho-modification of Tyr in thermophiles suggests enhanced metabolic regulations in this group. Mechanisms of Protein Folding. Experimentally observed conformation-dependent geometry and hidden strain in proteins.
Beyond the extent of the compulsion of the peptide bond to remain in planarity, it may acquire a nonplanar structure depending on the nature of stress. At the gene level, the extrinsic selective force is found to be linked to the process of synonymous codon usage for some amino acids particularly for the arginine and isoleucine in thermophiles.
Mol Biol Evol. An extensive genome-wide study of related species of Archaea and Bacteria suggests that, natural selection dominates to eliminate non-synonymous and synonymous mutation in thermophiles at a higher rate than in nonthermophiles [ 19 ].
The frequency zone was arranged in ascending order.