Flashcards
Protein types
Cards in this deck (9)
- 1Protein typesGlobular protein chain(s) are arranged in compact domains active components of the cellular ‘machinery’.
Fibrous protein chains are arranged into fibres. Have a structural role - 2Types of fibrous proteins (secondary strcutures)coiled-coil (e.g. keratin and myosin)
b-sheets (e.g. amyloid fibres and silks)
triple helix (the collagens) - 3Alpha keratin I- Mechanically durable
- In nails, hair etc.
Primary - a, b, c d, e, f, g repeated
- a and d are hydrophobic
- Two helices twist around each other, associating via the hydrophobic faces of the helices. COILED-COIL - 4Alpha keratin II- The coiled-coil dimer then lines up with another to form a staggered antiparallel tetramer
- tetramers - protofilaments - protofibrils - microfibrils - 5Fibroin I- Made by silkworms
Primary structure - Gly, Ser, Gly, Ala, Gly, Ala repeated
Secondary structure - antiparallel Beta sheet - 6Fibroin II- Silk is very strong due covalent bonds yet flexible due vdW between B sheets.
- The b-sheets can stack into layers of contacting Gly side chains alternating with layers of Ser/Ala side chains - 7Collagen I- The most abundant vertebrate protein
- In skin, bone etc
- 1/3 Gly and 15-30% Pro and hyrdoxypro - 8Collagen IIPrimary - Gly, pro, hyp repeated
Secondary - . Instead it forms a ‘loose’ helix with around three residues per turn - 9tertiary structure of collagen- Three collagen polypeptides wind around each other in a rope-like twist to form a TRIPLE HELIX
- Every 3rd Gy passes through the centre of the triple helix
- Pro and Hyp allow rigidity
- Inter-chain H bonds form
- Large, strong fibers form
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- Uni BIOL 111: Molecules of life Flashcards on Protein types, created by Jumael Zafar on 26/12/2018.
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- Jumael Zafar
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