Bke2 Biochemistry Lectures

Lecture 5: Protein chemistry, structure & function I
Reading material: Horton, Chapter 4.

Abstract: To a large extent, proteins are built up by ordered structures; the secondary structure elements a-helices and b-pleated sheet. These arise when the same phi/psi angles are repeated over a number of residues and are stabilised by hydrogen bonds involving the main chain carbonyl oxygen and peptide nitrogen. Secondary structural elements are joined by loops or turns, and are often combined in particular ways called motifs that in turn are combined to generate functional protein domains. The principles governing protein folding will be discussed in some detail, and protein folding in the cell briefly described. The structure of some fibrous proteins will also be briefly discussed.

Key concepts:
Secondary structure (a-helix, b-sheet)
Turns, loops
Motifs
Domains
Water soluble proteins have hydrophobic cores
The hydrophobic effect is the main driving force for protein folding
By forming secondary structure elements, the hydrophilic main chain regions are hidden from the hydrophobic interior of the protein
Stabilizing forces
Hydrogen bonds
van der Waals forces
Ionic interactions
Disulfide bonds
Inside cells, folding is often aided by chaperones.

Links:

Lecture index

[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35]