细胞膜和细胞表面
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鞘脂和胆固醇形成，厚度和构成均和周围不同，脂筏可以集中某些蛋白。 The first hint that lipids may be organized within the leaflets was the
discovery that the residues remaining after the extraction of plasma membranes with detergents contain two lipids: cholesterol and sphingomyelin. Because these two lipids are found in more ordered, less fluid bilayers, researchers hypothesized that they form microdomains, termed lipid rafts, surrounded by other more fluid phospholipids that are easily extracted by detergents.
膜脂可分为三大类，磷脂（磷脂甘油）， 鞘脂和胆固醇
A typical biomembrane is assembled from phosphoglycerides,sphingolipids, and steroids. All three classes of lipids are amphipathic molecules having a polar (hydrophilic) head group and hydrophobic tail.
sphingosine amino group.
胆固醇，有4个环，一个羟基（亲水） 前面两种膜脂可以单独或混合形成脂双层，胆固醇则不能形成
脂双层。
Cholesterol is especially abundant in the plasma membranes of mammalian cells but is absent from most prokaryotic cells. As much as 30–50 percent of the lipids in plant plasma membranes consist of certain steroids unique to plants.
Integral membrane proteins, Lipid-anchored membrane proteins Peripheral membrane proteins
蛋白穿膜部分的主要二级结构是α螺旋 Membrane-Embedded α Helices Are the Primary Secondary Structures in Most Transmembrane Proteins
磷脂甘油 3-磷酸甘油的衍生物 the most abundant class of lipids in most membranes, are derivatives of glycerol 3-phosphate .
Pho磷sp脂ha具tid有y2le个th脂an酰ola基m构in成e 的疏水性尾部和与磷 磷脂酸酰相乙连醇的胺亲水性头部 PhoAsptyhpaitcidalylpchhooslipnheoglyceride molecule consists 磷脂of酰a胆hy碱drophobic tail composed of two fatty Phoascpyhl acthidayinlsseerisnterified to the two hydroxyl 磷脂gr酰ou丝ps氨in酸glycerol phosphate and a polar head Phogsrpohuaptiadtytlaincohseidtotlo the phosphate group. 磷脂酰肌醇
Long, saturated fatty acyl chains have the greatest tendency to aggregate, packing tightly together into a gel-like state.
膜蛋白荧光标记脱色恢复实验
膜脂的运动方式
沿膜平面侧向运动 围绕轴心的自旋 分子尾部的摆动 双层分子间的翻转
鞘磷脂 sphingomyelins
Glucosylcerebroside，葡萄糖神经酰胺，是一 种糖脂，糖脂在神经组织最多 Glycolipids constitute 2–10 percent of the total lipid in plasma membranes; they are most abundant in nervous tissue.
血型糖蛋白，跨膜螺旋由20-25个疏水性氨基酸构成
Structure of glycophorin A, a typical singlepass transmembrane protein. Typically, a membraneembedded helix is composed of 20–25 hydrophobic (uncharged) amino acids. The predicted length of such a helix (3.75 nm) is just sufficient to span the hydrocarbon core of a phospholipid bilayer. The hydrophobic side chains protrude outward from the helix and form van der Waals interactions with the fatty acyl chains in the bilayer.
Lipid droplets are surrounded by a phospholipid monolayer
脂质体（liposome）
脂质体是根据磷脂分子可在水相中形成 稳定的脂双层膜的趋势而制备的人工膜。
脂质体的类型和应用
(a)水溶液中的磷脂分子团； (b)球形脂质体； (c)平面脂质体膜； (d）用于疾病治疗的脂质体的示意图
膜脂 Lipid Composition and Structural Organization
生物膜的结构基础， 脂质双分子层
Biomembranes: Lipid Composition and Structural Organization
膜脂——生物膜的基本组成成分
Three Classes of Lipids Are Found in Biomembranes
红色部分为鞘氨醇，具有一个长的碳氢链，一个氨基与 脂肪酸链相连，一个羟基和磷酸相连
All of these compounds are derived from sphingosine, an amino alcohol with a long hydrocarbon chain, and contain a long-chain fatty acid attached to the
离子通道也是多次跨膜蛋白家 族
钾离子通道由四聚体构成，每个亚单位有一对 跨膜螺旋，螺旋的方向改变调节离子的流动。
Ion channels compose a second large and important family of multipass transmembrane proteins. As revealed by the crystal structure of a resting K+ channel, ion channels are typically tetrameric proteins. Each of the four subunits has a pair of membrane-spanning helices that bundle with helices of other subunits, forming a central channel
七次跨膜螺旋在很多跨膜蛋白中存在，如G蛋 白偶联受体，细菌中的细菌视紫质。
A large and important family of integral proteins is defined by the presence of seven membrane-spanning α helices. Among them are the G protein–coupled receptors. The structure of bacteriorhodopsin, a protein found in the membrane of certain photosynthetic bacteria, illustrates the g细e菌ne视r紫a质l s结t构ru模c型ture of all these proteins
膜的侧面流动性和脂肪酸链长度，饱和或不饱和 脂肪酸，及温度有关。 膜脂的流动性限制了膜蛋白的流动性
The ability of lipids to diffuse laterally in a bilayer indicates that it can act as a fluid. The degree of bilayer fluidity depends on the lipid composition
in plasma membranes from human erythrocytes, almost all the sphingomyelin and phosphatidylcholine, both of which form less fluid bilayers, are found in the exoplasmic leaflet. In contrast, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, which form more fluid bilayers, are preferentially located in the cytosolic leaflet.
脂质体的应用 研究膜脂与膜蛋白及其生物学性质； 脂质体中裹入DNA可用于基因转移； 在临床治疗中,脂质体作为药物或酶等载体
膜蛋白 Biomembranes: Protein Components and Basic Functions
膜蛋白分内在蛋白，锚定蛋白，外周蛋 白
Proteins Interact with Membranes in Three Different Ways
脂双层结构的形成
the polar head groups in all phospholipids can pack together into the characteristic bilayer structure. Sphingomyelins are similar in shape to phosphoglycerides and can form mixed bilayers with them. Cholesterol and other steroids are too hydrophobic to form a bilayer structure unless they are mixed with phospholipids.
膜脂在细胞质侧和外侧的分布不一样
Membrane Lipids Are Usually Distributed Unequally in the Exoplasmic and Cytosolic Leaflets
在红细胞，鞘脂和磷脂胆碱，分布细胞外侧，磷脂乙 醇胺，磷脂丝氨酸，磷脂肌醇，分布在细胞内侧
discovery that the residues remaining after the extraction of plasma membranes with detergents contain two lipids: cholesterol and sphingomyelin. Because these two lipids are found in more ordered, less fluid bilayers, researchers hypothesized that they form microdomains, termed lipid rafts, surrounded by other more fluid phospholipids that are easily extracted by detergents.
膜脂可分为三大类，磷脂（磷脂甘油）， 鞘脂和胆固醇
A typical biomembrane is assembled from phosphoglycerides,sphingolipids, and steroids. All three classes of lipids are amphipathic molecules having a polar (hydrophilic) head group and hydrophobic tail.
sphingosine amino group.
胆固醇，有4个环，一个羟基（亲水） 前面两种膜脂可以单独或混合形成脂双层，胆固醇则不能形成
脂双层。
Cholesterol is especially abundant in the plasma membranes of mammalian cells but is absent from most prokaryotic cells. As much as 30–50 percent of the lipids in plant plasma membranes consist of certain steroids unique to plants.
Integral membrane proteins, Lipid-anchored membrane proteins Peripheral membrane proteins
蛋白穿膜部分的主要二级结构是α螺旋 Membrane-Embedded α Helices Are the Primary Secondary Structures in Most Transmembrane Proteins
磷脂甘油 3-磷酸甘油的衍生物 the most abundant class of lipids in most membranes, are derivatives of glycerol 3-phosphate .
Pho磷sp脂ha具tid有y2le个th脂an酰ola基m构in成e 的疏水性尾部和与磷 磷脂酸酰相乙连醇的胺亲水性头部 PhoAsptyhpaitcidalylpchhooslipnheoglyceride molecule consists 磷脂of酰a胆hy碱drophobic tail composed of two fatty Phoascpyhl acthidayinlsseerisnterified to the two hydroxyl 磷脂gr酰ou丝ps氨in酸glycerol phosphate and a polar head Phogsrpohuaptiadtytlaincohseidtotlo the phosphate group. 磷脂酰肌醇
Long, saturated fatty acyl chains have the greatest tendency to aggregate, packing tightly together into a gel-like state.
膜蛋白荧光标记脱色恢复实验
膜脂的运动方式
沿膜平面侧向运动 围绕轴心的自旋 分子尾部的摆动 双层分子间的翻转
鞘磷脂 sphingomyelins
Glucosylcerebroside，葡萄糖神经酰胺，是一 种糖脂，糖脂在神经组织最多 Glycolipids constitute 2–10 percent of the total lipid in plasma membranes; they are most abundant in nervous tissue.
血型糖蛋白，跨膜螺旋由20-25个疏水性氨基酸构成
Structure of glycophorin A, a typical singlepass transmembrane protein. Typically, a membraneembedded helix is composed of 20–25 hydrophobic (uncharged) amino acids. The predicted length of such a helix (3.75 nm) is just sufficient to span the hydrocarbon core of a phospholipid bilayer. The hydrophobic side chains protrude outward from the helix and form van der Waals interactions with the fatty acyl chains in the bilayer.
Lipid droplets are surrounded by a phospholipid monolayer
脂质体（liposome）
脂质体是根据磷脂分子可在水相中形成 稳定的脂双层膜的趋势而制备的人工膜。
脂质体的类型和应用
(a)水溶液中的磷脂分子团； (b)球形脂质体； (c)平面脂质体膜； (d）用于疾病治疗的脂质体的示意图
膜脂 Lipid Composition and Structural Organization
生物膜的结构基础， 脂质双分子层
Biomembranes: Lipid Composition and Structural Organization
膜脂——生物膜的基本组成成分
Three Classes of Lipids Are Found in Biomembranes
红色部分为鞘氨醇，具有一个长的碳氢链，一个氨基与 脂肪酸链相连，一个羟基和磷酸相连
All of these compounds are derived from sphingosine, an amino alcohol with a long hydrocarbon chain, and contain a long-chain fatty acid attached to the
离子通道也是多次跨膜蛋白家 族
钾离子通道由四聚体构成，每个亚单位有一对 跨膜螺旋，螺旋的方向改变调节离子的流动。
Ion channels compose a second large and important family of multipass transmembrane proteins. As revealed by the crystal structure of a resting K+ channel, ion channels are typically tetrameric proteins. Each of the four subunits has a pair of membrane-spanning helices that bundle with helices of other subunits, forming a central channel
七次跨膜螺旋在很多跨膜蛋白中存在，如G蛋 白偶联受体，细菌中的细菌视紫质。
A large and important family of integral proteins is defined by the presence of seven membrane-spanning α helices. Among them are the G protein–coupled receptors. The structure of bacteriorhodopsin, a protein found in the membrane of certain photosynthetic bacteria, illustrates the g细e菌ne视r紫a质l s结t构ru模c型ture of all these proteins
膜的侧面流动性和脂肪酸链长度，饱和或不饱和 脂肪酸，及温度有关。 膜脂的流动性限制了膜蛋白的流动性
The ability of lipids to diffuse laterally in a bilayer indicates that it can act as a fluid. The degree of bilayer fluidity depends on the lipid composition
in plasma membranes from human erythrocytes, almost all the sphingomyelin and phosphatidylcholine, both of which form less fluid bilayers, are found in the exoplasmic leaflet. In contrast, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, which form more fluid bilayers, are preferentially located in the cytosolic leaflet.
脂质体的应用 研究膜脂与膜蛋白及其生物学性质； 脂质体中裹入DNA可用于基因转移； 在临床治疗中,脂质体作为药物或酶等载体
膜蛋白 Biomembranes: Protein Components and Basic Functions
膜蛋白分内在蛋白，锚定蛋白，外周蛋 白
Proteins Interact with Membranes in Three Different Ways
脂双层结构的形成
the polar head groups in all phospholipids can pack together into the characteristic bilayer structure. Sphingomyelins are similar in shape to phosphoglycerides and can form mixed bilayers with them. Cholesterol and other steroids are too hydrophobic to form a bilayer structure unless they are mixed with phospholipids.
膜脂在细胞质侧和外侧的分布不一样
Membrane Lipids Are Usually Distributed Unequally in the Exoplasmic and Cytosolic Leaflets
在红细胞，鞘脂和磷脂胆碱，分布细胞外侧，磷脂乙 醇胺，磷脂丝氨酸，磷脂肌醇，分布在细胞内侧