上游究更大学 2.A Pair of Nucleic Acid Chains with Complementary SHANGHAI JIAO TONG UNIVERSITY Sequences Can Form a Double-Helical Structure Watson-Crick的DNA双螺旋结构模型 I34A层距 小沟 Minor groove 34A 大沟 Major 34A 螺距 groove 20A 直径 右手双螺旋2. A Pair of Nucleic Acid Chains with Complementary Sequences Can Form a Double-Helical Structure Watson-Crick的DNA双螺旋结构模型 大沟 小沟 螺距 层距 右手双螺旋 34 A 直径