第四章 细胞质膜
陈建国 北京大学 生命科学学院
Cell membranes act as selective barriers
Cell membranes act asselective barriers
Internal membranes form many different compartments in a eukaryotic cell
Amphipathic phospholipids form a bilayer in water
Figure 10-8 Molecular Biology of the Cell (© Garland Science 2008)
Pure phospholipids can form closed, spherical liposomes.
β barrels formed from different numbers of β strands
A single-pass transmembrane protein
Figure 10-27 Molecular Biology of the Cell (© Garland Science 2008)
Membrane Proteins Can Be Solubilized and Purified in Detergents
Figure 10-30 Molecular Biology of the Cell (© Garland Science 2008)
The use of mild nonionic detergents for solubilizing, purifying, and reconstituting functional membrane protein systems.
The carbohydrate layer on the cell surface
Figure 10-28a Molecular Biology of the Cell (© Garland Science 2008)
Figure 10-28b Molecular Biology of the Cell (© Garland Science 2008)
Figure 10-19 Molecular Biology of the Cell (© Garland Science 2008)
肉豆蔻酰,十四酰
棕榈酰,十六酰,软脂酰
法呢基
Membrane protein attachment by a fatty acid chain or a prenyl group.
Figure 10-20 Molecular Biology of the Cell (© Garland Science 2008)
Figure 10-21 Molecular Biology of the Cell (© Garland Science 2008)
A segment of a membrane-spanning polypeptide chain crossing the lipid bilayer as an α helix.
A model of a Lipid Bilayer Is Functionally Important
The asymmetrical distribution of phospholipids and glycolipids in the lipid bilayer of human red blood cells.
Pure phospholipids can form closed, spherical liposomes.
Figure 10-11b Molecular Biology of the Cell (© Garland Science 2008)
Table 10-1 Molecular Biology of the Cell (© Garland Science 2008)
Phosphatidylcholine is the most common phospholipid in cell membranes
磷脂酰乙醇胺, 脑磷酯
磷脂酰丝氨酸, 丝氨酸磷脂
磷酸卵磷酯
鞘磷脂
鞘氨醇, 神经鞘氨醇
The structure of cholesterol
Cholesterol in a lipid bilayer.
Two views of a cell membrane. (A) An electron micrograph of a segment of the plasma membrane, showing its bilayer structure. (B-C) A three-dimensional schematic view of a cell membrane and the general disposition of its lipid and protein constituents. It is estimated that about 30% of the proteins encoded in an animal’s genome are membrane proteins.
Many Membrane Proteins Diffuse in the Plane of the Membrane
An experiment demonstrating the diffusion of proteins in the plasma membrane of mouse–human hybrid cells
Membrane Proteins
Plasma membrane proteins have a variety of functions
Figure 13-1 Molecular Biology of the Cell (© Garland Science 2008)
Various ways in which proteins associate with the lipid bilayer