The Three-Dimensional Structure of Proteins

Flashcards covering vocabulary terms and definitions related to the three-dimensional structure of proteins, including peptide bonds, protein structure levels, and specific protein types.

Peptide Bond

A covalent linkage between amino acids formed by condensation reactions involving the loss of a water molecule.

Primary Structure

The linear sequence of amino acids in a polypeptide, presented from the N (amino) terminus to the C (carboxyl) terminus.

Secondary Structure

Localized patterns of folding in a polypeptide maintained by hydrogen bonds between main-chain amide and carbonyl groups.

Tertiary Structure

Final folding pattern of a single polypeptide, determining the biological active structure.

Quaternary Structure

The folding pattern when multiple polypeptides are involved, typically involving non-covalent interactions.

α-Helix

A right-handed helix with 3.6 residues per turn, stabilized by hydrogen bonds parallel to the axis of the helix.

β-Sheet

Involves multiple β strands arranged side-by-side, stabilized by hydrogen bonds between adjacent strands.

Hydrogen Bonding

An interaction that plays a critical role in maintaining secondary structure through attractions between electropositive and electronegative atoms.

Steric Interference

A phenomenon where two groups cannot occupy the same space at the same time, affecting molecular conformation.

Denaturation

The disruption of native conformation in proteins, resulting in the loss of biological activity.

Amphipathic Helix

A helix that exhibits both hydrophilic and hydrophobic regions, influencing its behavior in biological environments.

Disulfide Bonds

Covalent linkages between cysteine residues, contributing to the stabilization of protein structure.

Prion

A misfolded self-protein capable of inducing abnormal folding in other proteins, leading to neurodegenerative diseases.

Vitamin C

A nutrient required for the post-translational modification of collagen that stabilizes its structure.

Osteogenesis Imperfecta

A genetic disorder characterized by brittle bones, often associated with abnormalities in collagen structure.