Protein Shape

Protein shape determines...

its function

Protein conformation

Three-dimensional shape of a protein.

Native Conformation

the correct folding pattern that makes a protein functional

Primary Structure

The amino acid structure of a polypeptide chain.

secondary structure

the hydrogen bonded connections in a repeating peptide unit; contains alpha helices and beta-plated sheets

Alpha Helix

Spiral structure where the carboxyl group of one residue is hydrogen bonded to an anime group a few residues away.

Disrupts alpha helix

Proline, large, or charged R groups

Denaturation

destroys H bonds

Alpha helix arrangement

can be arranged based on hydrophilic or hydrophobic

Beta-Plated Sheets

AA connected laterally by H bonds between a peptide bond

parallel beta pleated sheet

Peptide strands run in same direction; 1:2 ratio; Unstable H bonds

anti-parallel beta sheet

peptide strands run in opposite direction; 1:1 ratio; stable H bonds

What determines if the secondary structure is alpha helix or beta plated sheets?

The R group

Secondary structures can...

Turn, loop, and twist

Motifs

group of secondary structures that cluster together to carry out a specific function; linked via turns and loops

Domain

large part of the protein that has a specific function; can continue its job even if its separated from the rest of the protein; can contain several motifs

Fibrous Protein

long, straight, and narrow fiber strands that are strong and stable; provide structural support to the cell; mostly primary and secondary structure; Ex: collagen

Globular

Peptide chains that fold back on themselves and create specific receptor sites for functionality; has tertiary structure

Collagen

Glycine next to the proline allows the chain to fold back on itself in reverse turns and loops; Made up of a triple helix; no H bonds holding strands together

What holds collagen together?

A hydroxyl group added to proline with cofactor vitamin C; the OH from hydroxyproline forms bonds between the strands

Osteogenesis Imperfecta

Brittle Bone Disease; defect in collagen

dentinogenesis imperfecta

Disorder of tooth development; causes weak and translucent teeth

Scurvy

Condition caused by deficient vitamin C; Results in bruising, bleeding gums; weakness; fatigue, and rashes

Tertiary Structure

3d structure of a single polypeptide chain; includes cofactors, side chains, and secondary structures

Bonds that hold the tertiary structure

H bonds, covalent bonds, disulfide bonds, hydrophobic forces, Van der waal forces, electrostatic forces

Complex

protein made up of more than one polypeptide chains

Subunit

an individual polypeptide chain in the protein complex

Quaternary structure

the arrangement of subunits and their interactions

Bonds that hold the quaternary structure

H bonds, covalent bonds, disulfide bonds, hydrophobic forces, Van der waal forces, electrostatic forces

A conformational change in one subunit can cause a change in the rest of the protein

True

Allosteric

Change that takes place when the protein/enzyme is bound to a substrate; can be initiated by the hydrophobic effect

Protein denaturation is caused by...

Heat, pH changes, reducing agents

Improper folding of proteins can cause diseases such as

Cataracts, Mad Cow, Alzheimer's, Parkinsons

Chaperone Protein

Specialized protein that aid protein folding