Biomaterial Database

Composition-related structural transition of random peptides: insight into the boundary between intrinsically disordered proteins and folded proteins. 2019

Wen-Bin Kang, and Chuan He, and Zhen-Xing Liu, and Jun Wang, and Wei Wang

a School of Physics , Nanjing University , Nanjing 210093 , P.R. China.

Previous studies based on bioinformatics showed that there is a sharp distinction of structural features and residue composition between the intrinsically disordered proteins and the folded proteins. What induces such a composition-related structural transition? How do various kinds of interactions work in such processes? In this work, we investigate these problems based on a survey on peptides randomly composed of charged residues (including glutamic acids and lysines) and the residues with different hydrophobicity, such as alanines, glycines, or phenylalanines. Based on simulations using all-atom model and replica-exchange Monte Carlo method, a coil-globule transition is observed for each peptide. The corresponding transition temperature is found to be dependent on the contents of the hydrophobic and charged residues. For several cases, when the mean hydrophobicity is larger than a certain threshold, the transition temperature is higher than the room temperature, and vise versa. These thresholds of hydrophobicity and net charge are quantitatively consistent with the border line observed from the study of bioinformatics. These results outline the basic physical reasons for the compositional distinction between the intrinsically disordered proteins and the folded proteins. Furthermore, the contributions of various interactions to the structural variation of peptides are analyzed based on the contact statistics and the charge-pattern dependence of the gyration radii of the peptides. Our observations imply that the hydrophobicity contributes essentially to such composition-related transitions. Thus, we achieve a better understanding on composition-structure relation of the natural proteins and the underlying physics.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009010	Monte Carlo Method	In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo. (From Random House Unabridged Dictionary, 2d ed, 1993)	Method, Monte Carlo
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic
D017510	Protein Folding	Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.	Protein Folding, Globular,Folding, Globular Protein,Folding, Protein,Foldings, Globular Protein,Foldings, Protein,Globular Protein Folding,Globular Protein Foldings,Protein Foldings,Protein Foldings, Globular
D055672	Static Electricity	The accumulation of an electric charge on a object	Electrostatic,Electrostatics,Static Charge,Charge, Static,Charges, Static,Electricity, Static,Static Charges
D057927	Hydrophobic and Hydrophilic Interactions	The thermodynamic interaction between a substance and WATER.	Hydrophilic Interactions,Hydrophilic and Hydrophobic Interactions,Hydrophilicity,Hydrophobic Interactions,Hydrophobicity,Hydrophilic Interaction,Hydrophilicities,Hydrophobic Interaction,Hydrophobicities,Interaction, Hydrophilic,Interaction, Hydrophobic,Interactions, Hydrophilic,Interactions, Hydrophobic
D064267	Intrinsically Disordered Proteins	Functional proteins that do not have unique, stable, folded, three-dimensional native structures or that possess non-ordered regions under physiological conditions. They are characterized by extraordinary structural flexibility and plasticity, which enable them to adopt different conformations in response to different stimuli or different interactions.	Intrinsically Disordered Protein,Natively Unfolded Protein,Unstructured Protein,Natively Unfolded Proteins,Unstructured Proteins,Disordered Protein, Intrinsically,Protein, Intrinsically Disordered,Protein, Natively Unfolded,Protein, Unstructured,Unfolded Protein, Natively