ATGC 2
Buffer r l了 Gel CCGGAAGCATAAAG TGTACAT Scan area Laser Spinning filter tube Buffer Photomultiplier To computer pcbs ocpa detection tube
The ABzs ofDna Secondary structure See Figure 12.10 for details of dna secondary structure Sugar-phosphate backbone outside Bases(hydrogen-bonded)inside Right-twist closes the gaps between base pairs to 3. 4A (0.34 nm) in B-DNA
The ABZs of DNA Secondary Structure • See Figure 12.10 for details of DNA secondary structure • Sugar-phosphate backbone outside • Bases (hydrogen-bonded) inside • Right-twist closes the gaps between base pairs to 3.4 A (0.34 nm) in B-DNA
(a)Ladder (b) Helix 0.6nm Base-pair acIn spacing 0.34nm G Pitch length 3.4nm & G G cI 5T G 3CI
The“ canonical数” base pairs See figure 12.10 The canonical A: T and G: c base pairs have nearly identical overall dimensions统一外形尺寸 a and t share two hbonds G and c share three hbonds G: C-rich regions of dNa are more stable Polar atoms in the sugar-phosphate backbone also form h bonds
The “canonical规范的 ” base pairs See Figure 12.10 • The canonical A:T and G:C base pairs have nearly identical overall dimensions 统一外形尺寸 • A and T share two H-bonds • G and C share three H-bonds • G:C-rich regions of DNA are more stable • Polar atoms in the sugar-phosphate backbone also form H-bonds