Biochem 2.3 Protein Folding and Stability

The process by which proteins adopt their functional three-dimensional shape.

The tendency of hydrophobic (water-fearing) amino acids to cluster together inside a protein structure, away from water.

A cage-like structure formed by water molecules surrounding dissolved molecules.

The state of order or disorder within a system. Higher entropy means more disorder.

The energy released or absorbed during the formation or breaking of bonds.

The energy released when a protein folds, driving the process towards a lower energy state.

The measure of the tendency for a process to occur spontaneously. A negative free energy change means the process is spontaneous.

Local secondary structures, such as α-helices and β-strands, tend to form early during protein synthesis based on the amino acid sequence.

Proteins can explore different conformations during folding, but ultimately funnel towards the lowest-energy conformation.

Proteins are not static; their atoms and bonds constantly move, leading to small changes in shape.

Unstructured regions in proteins are more flexible and prone to larger shape changes.

Structured regions of proteins, while less dynamic, can still undergo subtle shape changes.

Structured regions tend to reside in their lowest-energy conformation, but may briefly transition to higher-energy states.

Changes in the environment surrounding a protein can alter its energy landscape, favoring higher-energy conformations.

Proteins are highly specific in their function and have a preferred conformation that allows them to interact with other molecules.

The process where a protein unfolds and loses its tertiary and secondary structure, becoming nonfunctional.

The ability of a protein to change its shape in response to environmental conditions.

Molecules that bind to proteins and can influence their conformation.

Changes in the protein's primary structure due to alterations in the amino acid sequence, often caused by mutations.

Chemical alterations that can change the conformation of a protein, often affecting its function.

The average kinetic energy of the molecules in a system.

Substances that cause proteins to unfold or denature, often by disrupting the forces that stabilize protein structure.

The tendency for a protein to unfold or denature, becoming more favorable under certain conditions.

The forces that hold together a protein's structure, including hydrogen bonds, hydrophobic interactions, ionic bonds, and disulfide bonds.

The energy landscape of a protein's folding, which can be altered by changes in environmental conditions.

A measure of a protein's stability based on the temperature at which half the protein molecules in solution are denatured.

A stable, nonfunctional protein conformation that can trap a protein and prevent it from folding correctly.

Specialized proteins within cells that help other proteins fold correctly.

The process by which misfolded proteins are broken down into their component amino acids.

The change in pH that can disrupt the interactions between charged amino acid residues on the surface of a protein, leading to a change in shape and loss of function.

The change in salt concentration that can disrupt ionic interactions between charged amino acids on the protein surface, leading to partial denaturation.

A type of denaturing agent that has a hydrophobic tail that interacts with hydrophobic residues within a protein, disrupting the hydrophobic core and causing unfolding.

A long chain of amino acids linked together by peptide bonds.

The sequence of amino acids in a polypeptide chain.

The three-dimensional structure of a protein, which is determined by the interactions between different amino acids in the polypeptide chain.