Problem 18.3 Fibrous Protein Check all that apply. Structural proteins O Enzymes
ID: 1044990 • Letter: P
Question
Problem 18.3 Fibrous Protein Check all that apply. Structural proteins O Enzymes, hormones, transport Water-insoluble O Usually water-soluble Contains many Gly and Pro residues. Amino acid composition varies; hydrophilic groups on the outside account for solubility er Large regions of ?-helix or ?-sheet. smaller regions of ?-helix or ?-sheet. Few interactions between side chains on the same backbone. Complex Tertiary Structure: determined by hydrophobic and hydrophilic groups on side chains, as well as by disulfide bonds OExplanation / Answer
1. Fibrous proteins form 'rod' or 'wire' -like shapes and are usually inert structural or storage proteins.They are mostly structural proteins that are responsible for organisms in support and protection such as forming connective tissue, muscle fibers, bones, and tendons.
2. Nearly all enzymes are globular proteins as in protein hormones, blood transport proteins, antibodies and nutrient storage proteins.
3,4. The amino chain in the fibrous proteins can't twist in the way such that polar group lies at the surface and hence, are generally insoluble in water.
5. Many of the proteins contains residues of Gly (beta pleated sheet) while Gly and Pro in triple helix structures. Collagen is a common example.
6. In an protein, the interior consists on hydrophobic side chains while the surface consists of hydrophilic amino acids that interact with the aqueous environment and determine the solubility.
7,8. Folded proteins contain a considerable proportion of alpha helix or beta sheet. For example, myoglobin, an alpha-helical bundle, is 70% alpha helix and in addition to the same, other proteins may contain beta sheets or a mixture of both.
9. Fibrous proteins are rich in secondary structure while the tertiary structures containing the interaction between side chains are not rich and hence, include lesser interactions.
10. For amino acids, hydrogen bonding would occur between the backbone of the amine group and the oxygen of the carbonyl group.To add to it, the hydrophobic interaction originates from the tendency of non-polar molecules to minimize their interactions with water and form a micelle. In last, adisulfide bond can be form between two cysteines through oxidation and are strongest covalent bonds within a protein's tertiary structure.