BCH311H1 Lecture Notes - Lecture 2: Sticky And Blunt Ends, Psy, Ribonuclease
26 Aug 2018
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BCH311 – Lecture 2: RNA Structure and Techniques
RNA: Complex Secondary and Tertiary Structures are important for Function
• Transfer RNA(tRNA)
o Carrying AA for protein synthesis
• Ribosomal RNA(rRNA)
• Catalytic RNAs (Ribozymes)
o Structure is important for folding formation
• Riboswitches
• Primarily single-stranded RNAs
o Don't typically have H-bonding or secondary structure
o Messenger RNA (mRNA)
o MicroRNA (miRNA)
RNA Structures
• Single stranded RNA can form various structures
o Can form based on different interactions
o Can have 2 regions of the molecule coming together to for a structure
• Complementary sequences in RNA can join via intrastrand base pairing
• When the base pairing is not complete, a variety of bulges and loops can form,
including hairpin stem-loop structures
Transfer RNAs (tRNAs)
• Each AA with distinct tRNA
• Transfer RNAs carry amino acids to ribosomes for use in protein synthesis
• Each amino acid has at least one unique tRNA
• Small polynucleotide chains:
o Nucleotide residues
o 73 to 94 residues each
• Contains modified bases and multiple interactions creating a L-shaped molecule
o One end binding to mRNA molecules and the other to bind with AA
Basic tRNA Secondary Structure
• Cloverleaf structure with different loops
o Green → phosphodiester backbone
o Short regions of H-bonding
Details of the tRNA Secondary Structure
• How does it know to fold?
o These are interactions that take place between the nucleotides
o When the stretch "bumps" into the other, recognized the possibility for
desired H bonding and attaches
Tertiary Structure Formation
• Loops interact to make a more complex structure
• Narrow structure to allow tRNAs to come in
• Lots of interactions to stabilize the structure under denaturing or unfolding
• Acceptor stem shifts to the right
• Loop 2 and 4 come together to form an "elbow" and the Anti-codon at the
bottom
• The H-bonding is also co-operative here
Document Summary
Bch311 lecture 2: rna structure and techniques. Basic trna secondary structure: cloverleaf structure with different loops, green phosphodiester backbone, short regions of h-bonding. Details of the trna secondary structure: how does it know to fold, these are interactions that take place between the nucleotides, when the stretch bumps into the other, recognized the possibility for desired h bonding and attaches. Loops interact to make a more complex structure: narrow structure to allow trnas to come in, acceptor stem shifts to the right. Lots of interactions to stabilize the structure under denaturing or unfolding. Loop 2 and 4 come together to form an elbow and the anti-codon at the bottom. The h-bonding is also co-operative here trnaphe structure: subscript numbers are different modifications to the bases that can occur, pink lines indicate interactions for the folding properties, first nucleic acid to be structurally characterized: alex rich (mit, 1974)
