Fibrous Proteins and Collagen

Flashcards on Fibrous Proteins and Collagen Structure

Fibrous Proteins

Folded into extended filaments or sheet-like structures with repeated amino acid sequences, relatively insoluble, and provide structural or protective function.

Collagen and Elastin

Examples of fibrous proteins found in the extracellular matrix, serving structural functions in the body as components of skin, connective tissue, and blood vessel walls.

Collagen Molecule

A long, rigid structure where three polypeptides (alpha chains) are wound around one another in a rope-like triple helix.

Collagen

The most abundant protein in the human body.

Collagen Alpha Chains

Collagen superfamily proteins held together by interchain hydrogen bonds, with variations in amino acid sequence resulting in slightly different properties.

Fibril-forming Collagens

Collagen types that include type I, II, and III, possessing a rope-like structure and characteristic banding patterns under an electron microscope.

Network-forming Collagens

Collagen types that include IV and VIII, forming a two-dimensional mesh that makes up a major part of basement membranes.

Fibril-associated Collagens

Collagen types that include IX and XII, binding to the surface of collagen fibrils and linking them to other components in the ECM.

Fibrous Collagen Protein

Has an elongated triple-helix structure stabilized by interchain hydrogen bonds and is rich in proline and glycine.

Proline

Facilitates the formation of the helical conformation of each alpha chain in collagen due to its ring structure, causing 'kinks' in the peptide chain.

Glycine

Found in every third position of each polypeptide chain in collagen, fitting into the restricted spaces where the three chains of the helix come together.

Hydroxyproline and Hydroxylysine

Nonstandard amino acids present in collagen, resulting from the hydroxylation of some proline and lysine residues after their incorporation into polypeptide chains.

Glycosylation

The enzymatic glycosylation of the hydroxyl group of hydroxylysine residues in collagen, involving the sequential attachment of glucose and galactose to the polypeptide chain.