help with biochem Proteins are synthesized in the body through the enzymatic act
ID: 197888 • Letter: H
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help with biochem
Proteins are synthesized in the body through the enzymatic actions of a protein-nucleic acid complex calledr Cacrkan Amino Acids the Ribosome. In the Ribosome, individual amino acids are brought together and connected into a growing chain of polypeptides (the identity and order of the amino acids brought in is determined by messenger RNA). Protein Chain Ribosome RNA Let's suppose that the Ribosome is instructed by the mRNA to synthesize a short polypeptide consisting of a Alanine, a Serine, a Cysteine, and a Lysine. I. Draw the four amino acids, and illustrate the mechanism by which these amino acids form together into a polypeptide chain. Pay close attention to the order of the amino acids, the directionality of the amino acid backbones, and the functional groups that link amino acids. inRNA Coo coge CH Alonine CHa Ala 2. In this reaction, what product(s) are created in addition to the polypeptide chain? After this polypeptide is made, a group of scientists isolate the peptide and are attempting to characterize it. 3. Based on its sequence, if the polypeptide is put into a buffer with a pH of 7, do you expect it to migrate towards the positive or negative electrode in a gel electrophoresis system? Explain why 4. Why is "gel necessary in electrophoresis? The polypeptide is then treated with a buffer containing fairly concentrated sodium hydroxide to remove any possible contamination, and the gel electrophoresis is re-run while in this buffer. 5. Draw the structure of the polypeptide under these conditions.Explanation / Answer
During protein synthesis, amino accyl tRNA is will carry amino acid and help in peptide bond formation. In this aminoacyl structure 3’end of tRNA, that contains –OH, group, will make a bond with –COOH group of amino acid. In synthesis reaction new amino acyl tRNA will come and amino group attack, nucleophile, on the –COOH group and make a peptide bond between two amino acids. In general, to avoid the stearic hindrance, side chains of bulky amino acids are placed in opposite direction.
After the reaction the tRNA that encode for the protein will release and water will form as a byproduct.
Scientist can characterize it by amino acid analysis where they will find the equvimolar solution of amino acids. Cysteine is bit difficult but some modification they evaluate the cysteine amount. Apart from mass spectrometry and other enzymatic digestion will use for analysis of polypeptide.
As you know that lysine is positively charge amino acid due to presence of amino group at side chain and its dissociation is very high pH. its pKa value is near to 11. Hence this polypeptide will contain net positive charge, hence, it will move towards the negative electrode.
Gel is working as inactive material where it provides different size of pores according to cross linking polymer. Different type of gels can be run according to need of experiment.
Sodium hydroxide will provide high pH that will remove the DNA and RNA contamination before running the gel.
At high pH all the positive charge amino group will disappear, NH2, and COO- form wil present. Side chain of amino acid will also contain – NH2 group.
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