"Protein folding is the physical process where a protein chain is translated into its native three-dimensional structure, typically a 'folded' conformation, by which the protein becomes biologically functional."
An exploration of the process by which proteins are synthesized and folded into their functional structures.
Amino acids: Building blocks of proteins; essential and nonessential amino acids.
Protein structure: Primary, secondary, tertiary, and quaternary structures of proteins.
RNA: Types of RNA involved in protein synthesis, including messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).
Transcription: The process of making mRNA from DNA.
Translation: The process of making a protein from mRNA.
Ribosome: The organelle where protein synthesis occurs.
Genetic code: The sequence of nucleotides on mRNA and the corresponding amino acid.
Protein folding: The process by which a protein attains its functional shape.
Molecular chaperones: Proteins that aid in the folding of other proteins.
Protein quality control: Mechanisms that ensure proper protein folding and prevent the accumulation of misfolded proteins.
Prion diseases: Diseases caused by misfolded proteins, such as Creutzfeldt-Jakob disease and mad cow disease.
Protein misfolding diseases: Diseases caused by misfolded disease-related proteins, such as Alzheimer's and Parkinson's diseases.
Post-translational modifications: Modifications made to proteins after they are synthesized, such as phosphorylation and glycosylation.
Protein degradation: The process by which proteins are broken down and recycled by the cell.
Protein synthesis inhibitors: Compounds that interfere with protein synthesis, such as antibiotics that target bacterial ribosomes.
Transcription: The process of copying genetic information from DNA into RNA. Enzymes called RNA polymerases are responsible for synthesizing RNA molecules that are complementary to a segment of DNA.
Translation: The process by which ribosomes read the sequence of codons in messenger RNA and use that information to string together amino acids to form a protein.
Spontaneous folding: A type of protein folding that occurs without the aid of any cellular machinery. The final folded structure is determined solely by the properties of the amino acids themselves and the aqueous environment in which the protein resides.
Assisted folding: Proteins that require additional assistance in order to fold into their proper structure. These can include molecular chaperones, which help proteins along the folding process by binding to stretches of protein that are prone to misfolding, or enzymes that participate in covalent bond formation.
Molecular chaperones: A class of proteins that assist in the folding and unfolding of other proteins by preventing incorrect interactions and helping to maintain the proper shape of the protein.
Post-translational modifications: Chemical modifications to a protein that occur after the initial formation of the polypeptide chain. Examples include phosphorylation, glycosylation, methylation, and acetylation.
Protein misfolding: The process by which a protein fails to fold into its intended conformation, leading to diseases such as Alzheimer’s, Parkinson’s, and cystic fibrosis.
"At this stage, the polypeptide lacks any stable (i.e., long-lasting) three-dimensional structure (see the left side of the first figure)."
"The folding of many proteins begins even during the translation of the polypeptide chain. The amino acids interact with each other to produce a well-defined three-dimensional structure, the folded protein (see the right side of the figure), known as the native state."
"The resulting three-dimensional structure is determined by the amino-acid sequence or primary structure (e.g., Anfinsen's dogma)."
"The correct three-dimensional structure is essential to function."
"Failure to fold into a native structure generally produces inactive proteins, but in some instances, misfolded proteins have modified or toxic functionality."
"Several neurodegenerative and other diseases are believed to result from the accumulation of amyloid fibrils formed by misfolded proteins, the infectious varieties of which are known as prions."
"Many allergies are caused by the incorrect folding of some proteins because the immune system does not produce the antibodies for certain protein structures."
"Denaturation of proteins is a process of transition from a folded to an unfolded state. It happens in cooking, burns, proteinopathies, and other contexts."
"The duration of the folding process varies dramatically depending on the protein of interest. When studied outside the cell, the slowest folding proteins require many minutes or hours to fold."
"The folding time scale of a protein depends on its size, contact order, and circuit topology."
"The fastest known protein folding reactions are complete within a few microseconds."
"Understanding and simulating the protein folding process has been an important challenge for computational biology since the late 1960s." Note: Due to the limitations of the model's output capacity, only 13 study questions have been provided.