Tertiary structure of fibrous proteins

Secondary structure of fibrous proteins?

Usually dominated by a single regular structure, usually insoluble, to be compact you need irregular

What fibrous proteins are dominated by a-helixes?

a-keratin (hair, feathers, nails)

What structures are regulated by B-sheets?

Fibroin 9silk), B-keratin

What primary structure does Collagen use?

Collagen (p2) helix

A-keratin filaments

N-terminal heads, c-terminal tails, alternating handedness for stability, dimmer of a-helices and coiled coil in between, super helix

High alanine and cysteine, vary in disulphide bonds depending on stability needed/felxibility

Super helix

Two chains in a diner are twisted in a left-handed coiled coil

Collagen

Important in skin and tendons, bones, teeth

Regular helical structure, three residues per turn, interchain H bonds, three chains combine to form right-handed super helix

Primary structure of collagen

Glycine-proline-hydroxyproline

Glycine is most important, ish pattern not always, important for where other a.a couldn’t fit

Rich in 4-hydroxyproline, 5-hydroxylysine

H-bonding of collagen

Between strands not within them

4-hydroxyproline

Confirmation of collagen helix, hydroxylation after protein synthesis, needs vitamin C to form properly (ascorbic acid)- maintains oxidation states of active sites

5-hydroxlysine

Needs vitamin c too, in collagen, cross linking is through: this, lysine, histidine (not disulphide like a-helix)