1 / 45 Chapter 1 Amino Acids to Proteins 1.1 Protein Composition 1.2 Protein Conformations 1.3 Protein Structure and Function: A Few Examples 1.4 The Dynamics of Proteins 1.5 Experiments 1.1 蛋白质的组成 1.2 蛋白质的构象 1.3 蛋白质的结构与 功能：几个例子 1.4 蛋白质动力学 1.5 实验研究

2 / 45 Chapter 1 Amino Acids to Proteins 第 1 章 氨基酸到蛋白质 Life is most directly the work of proteins. Proteins allow organisms to grow and reproduce. They provide shape, strength and movement. In the cell, proteins are everywhere and do almost everything. 生命几乎就是蛋白质 的杰作。蛋白质让生 物可以生长和繁殖。 它们为生物提供了外 形和力量，以及运动 功能。 在细胞中，蛋白质无 处不在，行使着几乎 任何功能。

3 / Protein Composition / 蛋白质的组成

4 / The twenty amino acids and their abbreviation

5 / 45 Structures of hydrophobic amino acids

6 / 45 Structures of the hydrophilic amino acids

7 / 45 Structures of the 20 common amino acids Negative charge Positive charge

8 / 45 The formation of a peptide bond

9 / 45 Partial double bond / 部分双键 Partial double bond

10 / 45 Rigid and flexible bonds 3D structure

11 / 45 N-terminus and C-terminus / N- 末端和 C- 末端

12 / Protein Conformations / 1.2 蛋白质的构象 Describing Protein Structure Chemical and Physical Basis for Protein Folding 描述蛋白质 的结构 蛋白质折叠的 化学和物理基础

13 / Describing Protein Structure

14 / 45 α helix / α 螺旋 Hydrogen bond

15 / 45 β sheet / β 折叠 Hydrogen bond

16 / 45 Parallel and antiparallel β sheets

17 / 45 Tertiary structure / 三级结构 αhelix βsheet Turn

18 / 45 Quaternary structure / 四级结构 One subunit

19 / 45 Physical interactions involved in protein folding 1) Covalent bonding 2) Hydrogen bonding 3) Ionic bonding 4) Van der Waals forces 5) Hydrophobic interaction Chemical and Physical Basis for Protein Folding

20 / 45 1) Covalent bond / 共价键 Shared electrons H－HH－H H +1 H Covalent bond

21 / 45 Covalent bond / 共价键 Covalent bond

22 / 45 Covalent bond / 共价键 Covalent bond

23 / 45 2) Hydrogen bond / 氢键 Hydrogen bond

24 / 45 Partial charges vs. Full charges Cl δ – δ + δ + Na

25 / 45 Hydrogen bond / 氢键 Hydrogen bond

26 / 45 3) Ionic bond / 离子键 The ionic bond of sodium chloride, NaCl Na +11 Cl +17

27 / 45 Ionic bond / 离子键 Glu Lys

28 / 45 4) Van der Waals forces / 范德华力 Atom 1 Atom 2 van der Waals force

29 / 45 Van der Waals forces vs. Ionic bond Atom 1 Atom 2 Van der Waals forces The atom itself has negative and positive parts The interaction is transient Ionic bond The whole atom is either negative or positive The interaction is stable Atom 1 Atom 2

30 / 45 Van der Waals forces vs. hydrogen bond Atom 1 Atom 2 Van der Waals forces The atom itself has negative and positive parts The interaction is transient Hydrogen bond The whole atom is either partially negative or positive The interaction is stable Atom 1 Atom 2 δ – δ + δ – δ +

31 / 45 5) Hydrophobic interaction ?

32 / 45 Nonpolar molecules are forced together Water molecules get contacts with each other.

33 / 45 Hydrophobic interaction / 疏水相互作用

34 / Protein Structure and Function carbonic anhydrase

35 / 45 Actin / 肌动蛋白 An actin filament

36 / 45 Kinesin / 驱动蛋白

37 / The Dynamics of Proteins

38 / 45 Induced-fit vs. lock-and-key models

39 / 45 ATP synthetase / ATP 合成酶

40 / 45 Allosteric regulation / 别构调节

41 / 45 lac repressor / lac 阻遏蛋白

42 / Experiments/ 1.5 实验研究 dialyse dialysis