Protein Structure and Folding

These flashcards cover key vocabulary related to protein structure and folding, essential for understanding biochemistry.

Primary structure

The amino acid sequence of a protein.

Secondary structure

Regular sub-structures in proteins such as alpha helices and beta sheets.

Tertiary structure

The three-dimensional structure of a single polypeptide chain.

Quaternary structure

The complex of protein molecules formed by multiple polypeptides.

Amide bond

The bond between the amino group of one amino acid and the carboxyl group of another.

Ramachandran plot

A graphical representation of the allowed angles of rotation around the backbone of a protein.

Alpha helix

A common secondary structure where the polypeptide chain coils into a helical shape.

Beta sheet

A secondary structure where strands of the protein are aligned next to each other and linked by hydrogen bonds.

Hydrophobic interactions

Interactions that occur between nonpolar molecules or parts of molecules in aqueous solutions.

Steric crowding

A situation in which atoms are in close proximity and may hinder the ideal spatial arrangement.

Turn

A short sequence in a protein that connects different secondary structures.

Helix-Loop-Helix motif

A structural motif in proteins formed by alternating helices and loop regions.

Zinc Finger Motif

A protein structural motif that stabilizes its fold using zinc ions.

Superfamilies

Groups of proteins that share similar structures but may have different functions.

Linus Pauling

A chemist known for his foundational work on protein secondary structures, including the alpha helix and beta sheet.

Helix-helix packing

The precise arrangement and interaction of two or more alpha helices within a protein structure, often driven by hydrophobic interactions.

Type I Beta Turn

A common type of eta -turn in proteins, characterized by specific dihedral angles for the second and third residues, and a hydrogen bond between the carbonyl oxygen of residue i and the amide hydrogen of residue i+3 . Typically has a residue at position i+2 that is not glycine.

Type II Beta Turn

A common type of eta -turn in proteins, characterized by specific dihedral angles for the second and third residues, and a hydrogen bond between the carbonyl oxygen of residue i and the amide hydrogen of residue i+3 . This turn often has glycine at position i+2 .