BIO206H5 Lecture Notes - Lecture 5: Noncoding Dna, Tata Box, Dna Ligase
Document Summary
Echo r1: binds dna, binds specific sequence of dna, protein catalyst. Catalytic processes require co-factor: magnesium is co-factor. Enzymes that cleave phosphodiester bonds in dna/rna. Exonucleases cut nucleic acids from the ends. Restriction enzymes: native to bacteria, defends against viral infection. Discovery for development of recombinant dna technology. First time rearranging dna outside of cell. Come from bacteria, have evolved from bacteria. Host cell needs to protect themselves from action of restriction enzymes. 5" to the left, 3" to the right. All type 2 restriction enzymes are homodimer because they bind symmetrically to dna. Have different amino acid sequences, but they still cut the same nucleotides. Can end up making a hybrid dna molecule. It didn"t exist before: artificial dna molecule. Enzyme allows 2 phosphodiester bonds, catalyzes formation of bonds. Dna ligase uses atp to drive formation of single phosphodiester bond. Eukaryotes: dna in nucleus, mitochondria, and chloroplast.
