Fig. 9-CO, Nucleic acid: how structure conveys information Genetic material Gene-chromosome 親子鑑定 ??? DNA-RNA- Protein deoxyribonucleic acid ribonucleic acid

Nucleic Acids Nucleic acid:Nucleic acid: a biopolymer containing three types of monomer units –a base derived from purine or pyrimidine (nucleobases) –a monosaccharide, either D-ribose or 2-deoxy-D- ribose (nucleoside) –phosphoric acid RNA (Ribonucleic Acid) DNA (Deoxyribonucleic Acid) Nucleotide ( 核甘酸 )

Fig. 9-1 Common nucleobases: primary structure

Fig. 9-2, Less common nucleobases

Fig. 9-3, Ribonucleoside & deoxyribonucleoside:  -D-ribose and nucleobase N-glycosidic linkage N1-pyrimidine N9-purine

Fig. 9-4, Adding phosphoric acid-nucleotide AMP, ADP, ATP Esterified

Fig. 9-4a (1), p. 238

Fig. 9-5, Polymerization 3’,5’-phosphodiester bond Sugar-phosphate backbone pApCpGpU

Fig. 9-6, pd(TGCA)

The DNA family tree fossil Ancient DNA amber (polynucleotides)

Nucleic Acids Levels of structure –1°structure: the order of bases on the polynucleotide sequence; the order of bases specifies the genetic code –2°structure: the three-dimensional conformation of the polynucleotide backbone –3°structure: supercoiling –4°structure: interaction between DNA and proteins

Fig. 9-7, Double helix Watson & Crick-X ray One turn—3.4 nm 10 base pairs Negative charge Major & minor groove Antiparallel Complementary strand A=T, G=C secondary structure

Fig

Fig. 9-9a, B-DNA-major: 10 bp-right-handed Z-DNA-GC rich left –handed A-DNA-11bp, not in vivo (dehydrated DNA), right handed

Fig. 9-10,

Fig. 9-11, GC rich Zigzag: 180 O

Fig. 9-12, Best pairing (but not stacking) Helical twist Expose to water at minor groove

Fig. 9-13, Stacking-propeller-twisted base pairs Eliminate water contact Ring portion is hydrophobic Stacking better than pairing

Fig. 9-15, Supercoiled DNA-tertiary structure

Fig Topoisomerase-type1: one strand type2: double strand DNA gyrase

Fig Chromatin-DNA+ Protein (histone) Histone-positive charge H1, H2A, H2B, H3, H4 Nucleosome 150 base pairs and (H2A)2(H2B)2(H3)2(H4)2 Spacer region: base pairs and histone 1 & others The structure of chromatin

Insertion deletion Insertion and deletion Mutation rate around nucleosome Nucleotide changes

Methylation and Acetylation of histones regulates expression of genes Gene off Gene on Disease and epigenetic states Cancer immune deficiencies Diabetes heart disease DNA methylation: shutting off

Why identical twins are not identical Microarrays coded to show epigenetic differences DNA sequence is the same Gene expression DNA methylation—5-methylcytosine Turn off expression (in Z DNA)

Fig DNA denaturation H bond, stacking Melting hyperchromicity OD260 nm

Fig DNA denaturation PCR reaction (amplification of DNA)

Fig Information transfer in cells Replication Transcription Translation

Fig The role of mRNA in transcription snRNPs: snRNA + proteins mRNA: Small amount and Very short-lived nts

Table 9-1

Fig Transfer RNA-cloverleaf 1 amino acid :1 tRNA or more 80 nts Stem and loop

Fig Modified bases in transfer RNA

Fig Three dimensional structure of tRNA 3 nucleotides: 1 amino acid

Fig E. Coli 70S Reduce Mg 2+ dissociation reversible The structure of typical ribosome antibiotics

Fig The analytical ultracentrifuge Sedimentation coefficient Svedberg unit (S) Molecular weight and shape

Fig Secondary structure for 16S ribosomal RNA 1500 nts 500 KDa

Micro RNA : Regulation of gene Expression dsRNA (siRNA): Used by scientists to knock down a gene Adopted from giuworld.com

The human Genome project 3.3 billion base pair 30,000 genes (25,000) Ethical Legal Social implications Gene therapy Genome on a ID card Synthetic genome created (2009) Watermark—blue colonies