I. Protein Synthesis/Translation (First part is in last lecture but this is start of new EXAM)A. 3 processes: Initiation, Elongation and TerminationB. Initiation-1. first the 40s comes in with ribosomal binding region- No 60s yet2. Initiation factor 1 (IF1) help to escort the tRNA (1st one always carries methionine) so that it sits in there just perfectly3. Initiation factor 2 (IF2) helps to escort the tRNA (1st one always carries methionine) so that they sit together, anticodon and codon4. Initiation factor 3 (IF3)- lines up the message on the 40s ribosomal subunit, make sure it is in place, ready to do its job. 1st part of message lines up so 1st codon is correctly oriented (Always AUG)5. the IFs are all removed and the 60s is lined up with the 40sC. Elogation1. costly process to make proteins, so you can turn it off by phosphorylating IF2 to inhibit the tRNA attaching to the mRNAa) phosphorylation is a common regulatorb) this can be regulated by outside sources, a series of signals2. AUG= start3. 1st site = P site (peptidyl site or donor site)4. 2nd site = A site (acceptor site) – accepts incoming tRNA5. Proteins used for elongation (elongation factors): Tu, Ts, peptidyl transferase, G-translocasea) Tu (temperature unstable) and Ts (temperature stable) escort the tRNA into the ribosome and help the tRNA into the correct component of the ribosome, tight fit – needs GTP to provide the extra push(1) Elongation factors release after tRNA in place and GTP is usedb) Peptidyl transferase- recognizes the bond between the last adenine on the 3’ end of the tRNA and will take the amino acid at the carboxyl carbon of the tRNA in the P-site and attach it to the amino group at the A-site (making C-C-N1-C-C-N2)c) enzyme G-translocase- pull the mRNA 3 nucleotides through the ribosome, what was in the P-site is out, and the tRNA is released (relatively stable and used again), what was in the A-site is now in the P-site, and a new code is in the A-site---costs energy, needs to pay out some GTP6. Be aware of HUGE cost in this process7. All the information is ultimately coded by the gene itself, we are translating that information from the language of the gene to the language of the protein, hence the name.8. Average amino acids in a protein is 300, so as the peptide continues to grow (after it grows around 20 amino acids) it grows outside of the ribosome and begins to fold into its final form as its still being made (with secondary and tertiary structure)9. Mutationsa) sickle cell = one amino acid differenceD. Termination1. Stop codons : UAA, UGA, UAG- do not have amino acid anticodon but do have binding sites, they have a releasing factor known as R1 and R2a) R1 will recognize UAG and UAAb) R2 will recognize UAA and UGA2. releasing factors- R1 or R2 comes in like a bowling ball and knocks tRNA out and gets rid of the protein3. Protein IF3 will come in then and break the entire unit apart, it separates the 40s from the 60s and the mRNAa) IF3 is the same factor that begins protein synthesis and it also ends it, this way, it is there to immediately assemble another mRNA and ribosome to make another protein4. Antibiotics target protein synthesis; elogation, or termination in prokaryotes- cell dies, not immediately but will die eventually, why it takes a little bit for the antibiotics to worka) bad to take too much antibiotic because you could toxify yourself by stopping protein synthesis in the 80s ribosome and especially kill off the mitochondrial ribosomes. – they are built to effect the 70s ribosomes with regular dosageb) apply cycloheximide- block protein synthesis in the 80s ribosome5. Polysome- when you really need to make a protein, you will have multiple ribosomes bind to the same mRNA 80 nucleotides apart, they are seen often if you need a lot of a certain proteinBY 330 1st Edition Lecture 13 Outline of Last Lecture 4. Ribosome5. Transfer RNA6. Protein SynthesisOutline of Current Lecture I. Protein Synthesis/ TranslationA. 3 processes: Initiation, Elongation, TerminationB. InitiationC. ElongationD. TerminationCurrent LectureI. Protein Synthesis/Translation (First part is in last lecture but this is start of new EXAM)A. 3 processes: Initiation, Elongation and TerminationB. Initiation-1. first the 40s comes in with ribosomal binding region- No 60s yet 2. Initiation factor 1 (IF1) help to escort the tRNA (1 st one always carries methionine) so that it sits in there just perfectly3. Initiation factor 2 (IF2) helps to escort the tRNA (1 st one always carries methionine) so that they sit together, anticodon and codon 4. Initiation factor 3 (IF3)- lines up the message on the 40s ribosomal subunit, makesure it is in place, ready to do its job. 1st part of message lines up so 1st codon is correctly oriented (Always AUG)5. the IFs are all removed and the 60s is lined up with the 40s C. Elogation1. costly process to make proteins, so you can turn it off by phosphorylating IF2 to inhibit the tRNA attaching to the mRNA a) phosphorylation is a common regulatorThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b) this can be regulated by outside sources, a series of signals2. AUG= start 3. 1st site = P site (peptidyl site or donor site)4. 2nd site = A site (acceptor site) – accepts incoming tRNA5. Proteins used for elongation (elongation factors): Tu, Ts, peptidyl transferase, G-translocase a) Tu (temperature unstable) and Ts (temperature stable) escort the tRNA into the ribosome and help the tRNA into the correct component of the ribosome, tight fit – needs GTP to provide the extra push(1) Elongation factors release after tRNA in place and GTP is used b) Peptidyl transferase- recognizes the bond between the last adenine on the 3’ end of the tRNA and will take the amino acid at the carboxyl carbon of the tRNA in the P-site and attach it to the amino group at the A-site (making C-C-N1-C-C-N2)c) enzyme G-translocase- pull the mRNA 3 nucleotides through the ribosome, what was in the P-site is out, and the tRNA is released (relatively stable and used again), what was in the A-site is now in the P-site, and a new code is in the A-site---costs energy, needs to pay out some GTP6. Be aware of HUGE cost in this process7. All the information is ultimately coded by the gene itself, we are translating that information from the language of the gene to the language of the protein, hence the