Translation_geneexpinbrief_nucleus_structure_and_epigenetics

Translation_geneexpinbrief_nucleus_structure_and_epigenetics

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Genetic Code mRNA code to amino acid code
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Starting Translation
Background image of page 2
Degeneracy (redundancy) of the code UAU Tyr UGU Cys UAC Tyr UGC Cys UAA Stop UGA Stop UAG Stop UGG Trp In this small corner of the universal decoder chart you see that several codons can encode the amino acids or stop signals. Given amino acids tend to be encoded by related codons (UAU or UAC, for example). This helps reduce the likelihood that base substitutions change the amino acid sequence of a protein.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Base pairing can be sloppy (wobble) at the 3’ position of the codon U of tRNA can pair with A or G of mRNA G of tRNA can pair with U or C of mRNA I (inosine, derivative of guanine) can pair with U, C, or A
Background image of page 4
tRNA provides link between aa’s and codons 1 anti-codon can recognize > 1 mRNA codon For replication and transcription, the cell uses base pairing of complementary nucleotides… what about translation? The problem: the structures of amino acids and nucleotides are not complementary. The solution: tRNA serves as an intermediary. one end - attached to a specific amino acid other end - complementary to codon (“anticodon”)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
transfer RNA (tRNA) Made by RNA polymerase III in eukaryotes 70-90 nucleotides long Contains 1. a conserved region (3’-ACC) where the amino acid is attached and 2. a unique region called the “anticodon triplet” 3. The red and blue are the D and T arms, which help with recognition by the ribosome Amino acid binding site
Background image of page 6
Getting the tRNA ready for translation AA’s are added onto the free 3’ OH of tRNA This process is called “charging” -O-P-O-C-C-NH 2 O O O = R - H
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cellular machine for protein synthesis: ribosome Shown are the prokaryotic ribosome subunits Composition: two subunits: small & large 60% rRNA (initiation, alignment, peptide bond) 40% proteins 4.2 x 10 6 Da over 100,000 atoms X-ray structure (a big deal) See http://www.rcsb.org/pdb/molecules/pdb10_1.html 30S subunit 50S subunit
Background image of page 8
The 30S (small) and 50S (large) subunits come together to form three functional tRNA binding sites in bacteria: similar in eukaryotes The active sites on the ribosome for tRNA are mostly RNA
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Simplified view of the ribosome E
Background image of page 10
Translation Nobelprize.org Protein Synthesis Animation Video http://www.youtube.com/watch?v=Ikq9AcBcohA&feature=related
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Summary of initiation in prokaryotes or eukaryotes tRNA-Met binds IF2-GTP and small subunit tRNA-Met enters P site Small ribosome subunit binds to mRNA Initiation factors (IFs) helps assemble the small ribosome subunit-mRNA complex.
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 44

Translation_geneexpinbrief_nucleus_structure_and_epigenetics

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online