Translation and Post-translation 2C part 1 Flashcards
translation is the
assemble of amino acids into polypeptides
tell me the structure of an amino acid
amine group+central carbon+hydrigen+carboxyl group and a different R group
R group
This is what determines the unique character of an amino acid. What makes amino acid different
Tell me how two amino acids are joined (3)
+ what is the bond called
they are joined by a covalent peptide bond between the amino and carboxyl by a dehydration reaction.
The COH (part of COOH) reacts with the amine part hydrogen to form water molecule and the conjoined two amino acid.
carboxyl carbon join with amine nitrogen
Polypeptides
linear chains of amino acids linked by peptide bonds
Non polar amino acid
R group usually contain CH2 or CH3
uncharged polar amino acids
R groups usually contain oxygen of OH
charged amino acids
R groups contain acids or bases that can ionize
Aromatic amino acid
R group contain a carbon ring with alternating single and double bonds
Methionine
First amino acid in polypeptide
Proline
causes kink/bend in polypeptide chains
Cysteine
disulphide bridge where the R group interact
Primary amino acid sequence (3)
determines protein folding and 3D structure which is critical for proper function
just the linear sequence held together by peptide bond
no attention to 3D shape
Secondary protein structure (3)
depends on hydrogen bonding in the peptide backbone (alpha helices and beta-sheets).
secondary structure does not involve R group atoms
hydrogen bonds, which form between the carbonyl and amino group of the peptide bond
Tertiary protein structure (2)
the 3D structure of a single polypeptide and is composed of interactions between amino acid side chains
R groups interactions: ionic bonding, H bond, Vanderwall, Disulphide interaction and hydrophilic/hydrophobic
Quaternary protein structure (2)
Interactions between more than one polypeptide to form a multi-subunit proteins eg: hemoglobin
hydrogen bonds, covalent bonds, or ionic bonds.
how can protein structures be denatured (3)
heat
chemicals
mutations that change amino acid sequence
Chaperones (3)
protect slow folding or denatured proteins by preventing their aggregation
assist large proteins in proper protein folding during or after synthesis, and after partial denaturation
assist in protein folding by binding to and stabilizing folding intermediates until the polypeptide chain is fully translated.
aggregation (2)
associated with….
intrinsically-disordered or mis-folded proteins aggregate (i.e., accumulate and clump together)
associated with Alzheimer’s, Parkinson and Creutzfeldt-Jakob
tRNAs
adaptors between codons (mRNA) and amino acids
2-D 3 cloverleaf and 3-D L shaped folded RNA molecule from complimentary pairing.
Acceptor stem tRNA (2)
Where amino acid is attaches
contains the sequence 5’-CCA-3’ at the end of the 3’ end of tRNA
Anticodon (3)
the bottom loop of the cloverleaf contains three nucleotide sequence that recognize the codon by base pairing with mRNA
Each tRNA has its corresponding amino acid attached to its end.
anticodon binding to codon is antiparallel
aminoacyl-tRNA synthase (2)
adds amino acid to the acceptor stem of the correct tRNA
20 different aminoacyl-tRNA synthase for 20 different amino acids
charging reaction (3)
aminoacyl-tRNA synthase binds with ATP and amino acid causing two pyrophosphates to be released and ATP turns to AMP. Amino acid+AMP complex is formed
Correct tRNA binds with the enzyme.( Amine group free) The enzyme transfer amino group to tRNA. Amp is then released.
Amino acid-tRNA is released
