细胞与生物大分子.ppt

Cells and macromolecules Molecular Biology Course 中心粒 Glycoproteins are generated by the addition of oligosaccharide groups either to the NH2 group of asparagine (N-linked glycosylation糖基化) or to the OH group of serine, threonine, or hydroxylysine (O-linked glycosylation). N-linked glycosylation is initiated in the endoplasmic reticulum and completed in the Golgi; O-linked glycosylation occurs in the Golgi alone Proteoglycans (蛋白多糖): protein and mucopolysaccharide (粘多糖),bacterial cell walls and in the extracellular space in connective tissue. Lipid-linked proteins: covalently attached, the lipid moiety serves to anchor proteins in membranes and promotes protein-protein interaction. Lipoproteins (脂蛋白): proteins and lipids are linked noncovalently apolipoproteins (载脂蛋白),particles of triglycerides and cholesterol coated with a layer of phospholipids, cholesterol and protein (polar amino acids of the protein make the particles soluble). glycolipids(糖酯): lipids and carbohydrates are covalently linked. For example, cerebrosides (脑苷脂)and gangliosides (神经节甙Dai酯), 3、 Macromolecules 第四节、 Large macromolecular Assemblies protein complexes nucleoprotein membranes noncovalent interactions Protein complexes Long polymers of tubulin Fig.1. Schematic diagram showing the (a) cross-sectional and (b) surface pattern of tubulin a and b subunits in a microtubule (microfilament) actin and myosin, components of muscle fibers as well keratin (cilia and flagella) 4、 Large macromolecular Assemblies Crystal structure of 50S rRNA 4、 Large macromolecular Assemblies Nulceoptotein: associations of nucleic acids and protein (Section A4) Ribosome: consisting of ribosomal proteins and rRNA (structural function and catalytic function) Ribonuclease P: tRNA maturation, RNA catalyzes含有蛋白质和RNA两组分，蛋白无活性，RNA起催化作用，为核酶 Telomerase (端粒酶) : 由RNA和蛋白组成；使真核细胞染色体末端加上重复序列，replicating the ends of eukaryotic chromosomes, RNA acts as the replication template, and protein catalyze s the reaction Chromatin (染