Biochem 2.4 Protein Modifications Quiz

Changes in the amino acid sequence of a protein due to alterations in the corresponding gene.

The most common amino acid sequence of a protein found in nature.

A version of a protein with an amino acid sequence different from the wild-type.

A way to represent a protein mutation using the single-letter code for amino acids. For example, Q37L indicates that glutamine (Q) at position 37 is replaced by leucine (L).

A mutation that changes an amino acid to another with similar chemical properties, often having a smaller impact on the protein's function.

A mutation that changes an amino acid to one with significantly different chemical properties, potentially causing a major change in protein function.

The location of a mutation within a protein can influence its effect on the protein's structure and function.

The specific amino acid sequence of a protein determines its three-dimensional shape and function.

Mutations in flexible regions of a protein are less likely to significantly affect its function.

Mutations in highly structured regions of a protein are more likely to disrupt protein function.

Regions crucial for protein function may be affected even by conservative mutations - changes that maintain the same chemical properties.

Comparing protein sequences across different species reveals which amino acids are essential for function.

Amino acids that are crucial for protein structure and function are present in all species.

Amino acids that can be replaced by others with similar chemical properties are also conserved, but less strictly.

Amino acids that vary significantly across species are not conserved and may be less important for function.

The process of a ribosome synthesizing a protein.

Modifications to a protein after its synthesis, often involving adding chemical groups.

The transfer of a phosphate group to an amino acid residue, typically occurring on serine, threonine, or tyrosine.

The addition of an acetyl group (CH3CO) to a lysine residue in a protein.

The addition of a lipid molecule to a protein.

The process of breaking down a protein by hydrolyzing peptide bonds.

A non-amino acid molecule required for a protein's function.

A process where a phosphate group is added to an amino acid side chain, often regulating protein function.

Enzymes that catalyze the addition of a phosphate group to proteins.

The amino acids serine, threonine, and tyrosine are commonly phosphorylated, due to their hydroxyl groups acting as nucleophiles for phosphate group attachment.

The addition of a phosphate group can activate or inactivate a protein based on specific protein structure and function.

Mutations that replace serine or threonine with glutamate or aspartate can mimic the effect of phosphorylation, making a protein constitutively active.

The process of adding carbohydrate groups (sugars) to proteins, often occurring in the endoplasmic reticulum and Golgi apparatus.

Enzymes that catalyze the addition of carbohydrates to proteins.

A type of glycosylation that occurs on the -NH2 groups of asparagine side chains.

A type of glycosylation that occurs on the -OH groups of serine or threonine side chains.

The addition of carbohydrate groups can affect protein folding, stability, and interactions with other molecules.

A post-translational modification (PTM) where a small protein called ubiquitin is attached to a target protein. Ubiquitination often targets proteins for degradation by the proteasome, a cellular machinery that breaks down proteins.

A type of covalent bond that connects ubiquitin to the target protein through the side chain of lysine residues. This bond is similar to the peptide bond that links amino acids in a protein chain, but it forms between a side chain and a backbone group rather than two backbone groups.

A chain of ubiquitin molecules attached to a target protein. Polyubiquitination can signal for protein degradation by directing the protein to the proteasome.

A protein complex responsible for degrading proteins that are tagged with a ubiquitin chain. It breaks down proteins into smaller peptides and amino acids.

A molecule that carries acetyl groups and is involved in the acetylation of proteins. It's a key player in this PTM.

The N-terminus of a protein can also be a site for acetylation, similar to the lysine side chain. This PTM regulates protein function in various ways.