Fibrous Proteins: Structure and Function

This set of flashcards reviews key concepts related to the structure and function of fibrous proteins, including α-keratin, elastin, and collagen, as well as their roles in human health and disease.

What are the three main types of fibrous proteins discussed?

α-Keratin, Elastin, Collagen.

What is one function of α-keratin in the body?

It offers external protection and toughness.

How does elastin contribute to connective tissues?

It provides elasticity and stretchability.

What are the four main stages of collagen synthesis?

Procollagen, tropocollagen, assembly, crosslinking.

What is connective tissue?

Connective tissue fills spaces between organs and provides structural support.

Name a property of fibrous proteins.

They are insoluble in water.

What form does elastin take when stretched?

Fibrous form.

What type of structure is α-keratin primarily composed of?

α-helices.

What kind of linkage strengthens α-keratin?

Disulphide bridges.

What is tropoelastin?

The building unit of elastin.

What is the function of desmosine cross-links in elastin?

They provide a rubbery consistency to the elastin network.

What role does hydroxyproline play in collagen?

It forms hydrogen bonds between chains, contributing to collagen's strength.

How does type I collagen differ from type II collagen?

Type I contains two α1 chains and one α2 chain, while type II contains three α1 chains.

What are some clinical disorders associated with collagen synthesis?

Osteogenesis imperfecta, Ehlers-Danlos syndrome, scurvy, lathyrism.

What causes osteogenesis imperfecta?

A mutation in collagen where a glycine residue is changed to cysteine.

What is the clinical manifestation of Ehlers-Danlos syndrome?

Stretchable skin and hypermobile joints.

What is the significance of vitamin C in collagen formation?

It is required for the hydroxylation of proline and lysine residues.

What is lathyrism?

A disease caused by the inhibition of lysine oxidase, affecting collagen cross-linking.

What does collagen provide to connective tissues?

Tensile strength.

What happens during the assembly of tropocollagen?

A staggered array forms gaps for calcium phosphate deposition.

What is the importance of glycine in collagen structure?

It allows polypeptide chains to be very close to each other.

What is scurvy's effect on collagen fibrils?

It leads to poor formation of collagen fibrils.

What is the structural characteristic of collagen?

It consists of a triple helix structure.

What is a common symptom of scurvy?

Bleeding under the skin and fragile blood vessels.

What are the building blocks of collagen's structure known as?

Tropocollagen.