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1、Cells and macromolecules,Cells Procaryotic cell, Eucaryotic cell Macromolecules DNA, RNA, Protein, Lipids, Polysaccharides, Complex macromolecules,The universal phylogenetic tree based on 16S rRNA sequence,Carl Woese 2003 Crafoord Prize winner,Cellular classification,Procaryotic cell Eucaryotic cell
2、,Procaryotes Eucaryotes Eubacteria Archaea Structural 1-10m, pili, flagella, 10-100 m features no distinct subcellular organelles organelles Linkage (membrane ester ether ester lipids) Differentiation formation of spores embryonic cell differentiation,Cell wall to prevent cell lysis in environments
3、of low osmolarity Plasma membrane lipid bilayer and embedded proteins for small molecule exchange Genetic materials nucleoid (single and circular chromosome), plasmid Ribosomes protein synthesis machinery Pili to allow the cell to attach to other cells and surface Flagella cell movement,Subcellular
4、Organelles,Nuclei Mitochondria and chloroplasts Endoplasmic reticulum Microbodies,Glyoxysomes are specialized plant peroxisomes which carry out the reactions of glyoxylate cycle,Microbodies,Organelle isolation,Sedimentation coefficient (S) Supporting materials for density gradient centrifugation: su
5、crose, Ficoll, cesium chloride,Polysaccharides,Glycosidic bond,Lipids,Triglycerides Phospholipids,Complex macromolecules,Covalent or noncovalent associations of more than one major classes of large biomolecules which greatly increases the functionality or structural capabilities of the complex. Nucl
6、eoprotein Glycoprotein Lipoprotein,Large macromolecular Assemblies Protein complexes Nucleoprotein Membranes Noncovalent interactions,Protein complexes,Nucleoprotein,Ribosome ribosomal proteins rRNAs Chromatin DNA+histone (nucleosome) Virus protein capsid + RNA or DNA Telomerase replicating the ends
7、 of eukaryotic chromosomes. RNA acts as the replication template, and protein catalyzes the reaction Ribonuclease P protein + RNA, for tRNA maturation,Membrane,Bilayer lipids + proteins Acceptor Enzyme Channel Medium,Noncovalent interactions,Charge-charge interactions (salt bridges) charged molecule
8、s Charge-dipole, dipole-dipole either or both of the participants is a dipole . Dispersion interactions non-polar molecule van der Waals forces noncovalent associations between uncharged molecules. Hydrogen bonds: nucleic acids Hydrophobic interaction: proteins,Amino acids,Common structure of 19 AAs
9、,H3N+,COO-,R,H,C,Proline,a-carbon is chiral (asymmetric) except glycin (R is H) Only L-isomers are found in proteins Amino acids are dipolar ions in aqueous solution and are amphoteric The side chains (R) differ in size, shape, charge and chemical reactivity Nonstandard amino acids (e.g. 4-OH prolin
10、e and 5-OH lysine),Amino acids-charged (can form salt bridge, hydrophilic),Acidic amino acids containing additional carboxyl group,aspartic acid (Asp, D，天冬氨酸),glutamic acid (Glu, E，谷氨酸),Basic amino acids containing positively charged group,Lysine (Lys, K, 赖氨酸),Arginine (arg, R,精氨酸),Histidine (His, H
11、，组氨酸),Amino acids-polar uncharged (can form hydrogen bond with water, hydrophilic,Serine (Ser, S，丝氨酸),Threonine (Thr, T，苏氨酸),Asparagine (Asn, N，天冬酰氨),Glutamine (Gln, Q，谷氨酰氨),Cysteine (Cys, C，半胱氨酸) has a thiol group， which is often oxidizes to cystine,x-S-S-x,Tyrosine (Tyr, Y，酪氨酸),Amino acids-nonpola
12、r aliphatic (hydrophobic),Glycin (Gly, G，甘氨酸),Proline (Pro, P，脯氨酸),Methionine (Met, M，甲硫氨酸,Alanine (Ala, A，丙氨酸),Leucine (Leu, L，亮氨酸),Valine (Val, V，缬氨酸),Isoleucine (Ile, I，异亮氨酸),Amino acids-aromatic (UV absorbance at 280 nm, hydrophobic),Phenylalanine (Phe, F，苯丙氨酸),Tryptophan (Trp, W，色氨酸),Tyrosine (
13、Tyr, Y，酪氨酸),极性,Protein-shape,Globular proteins: enzymes,Fibrous proteins,Polypeptides contain N- and C- termini and are directional, usually ranging from 100-1500 aa,Formation of a peptide bond (shaded in gray) in a dipeptide.,a-helix right-handed 3.6 aa per turn hydrogen bond N-HO=C,Collagen triple
14、 helix: three polypeptide intertwined,A stereo, space-filling representation,Protein structure Secondary,b-sheet: hydrogen bonding of the peptide bond N-H and C=O groups to the complementary groups of another section of the polypeptide chains,A stereo, space-filling representation of the six-strande
15、d antiparallel b sheet.,Parallel b sheet: sections run in the same direction Antiparallel b sheet: sections run in the opposite direction,fibroin,A two-stranded b sheet,Protein structure Tertiary,The different sections of a-helix, b-sheet, other minor secondary structure and connecting loops of a po
16、lypeptide fold in three dimensions,Noncovalent interaction between side chains that hold the tertiary structure together: van der Waals forces, hydrogen bonds, electrostatic salt bridges, hydrophobic interactions Covalent interaction: disulfide bonds,Denaturation of protein by disruption of its 2o and 3o structure will lead to a random coil conformation,
