Assignments got your hair on fire?

Douse the flames with our full-range writing service!

Experienced academic writing professionals are at your fingertips. Use this handy tool to get a price estimate for your project.

, Li Shen, En Duo Wang, Ying Lai Wang

Modifications to the polypeptide often have to be made beforean active protein is formed. Insulin, for example, consists oftwo polypeptide chains connected by disulfide linkages. Intheory, it would be possible to make these chains one at a timeand then try to assemble them to make the final protein. Nature,however, has been more subtle. The polypeptide chain that issynthesized contains a total of 81 amino acids. All of thedisulfide bonds that will be present in insulin are present inthis chain. The protein is made when a sequence of 30 amino acidsis clipped out of the middle of this polypeptide chain.

This polypeptide is not necessarily an active protein. Allproteins in prokaryotic cells start with Met when synthesized,but not all proteins have Met first in their active form. It isoften necessary to clip off this Met after the polypeptide hasbeen synthesized to give a protein with a different N-terminalamino acid.

The sequence of DNA described in this section would producethe following sequence of amino acids.

/ ; Shen, Li; Wang, En Duo; Wang, Ying Lai.

Cookies are used by this site. To decline or learn more, visit our

The signal to start making a polypeptide chain in simple,prokaryotic cells is the triplet AUG, which codes for the aminoacid methionine (Met). The synthesis of every protein in thesecells therefore starts with a Met residue at the N-terminalend of the polypeptide chain. After the tRNA that carries Metbinds to the start signal on the messenger RNA, a tRNA carryingthe second amino acid binds to the next codon. A dipeptide issynthesized when the Met residue is transferred from the firsttRNA to the amino acid on the second tRNA. If the DNA describedin this section were translated, the dipeptide would be Met-Phe(reading from the N-terminal to the C-terminalamino acid).

Assume that the DNA chain that codes for the synthesis of a particular protein contains the triplet A-G-T (reading from the 3´ to the 5´ end). Predict the sequence of nucleotides in the triplet, or codon, that would be built in the messenger RNA constructed on this DNA template. Then predict the amino acid that would be incorporated at this point in the protein.

Tyynismaa, University of Helsinki, Finland.)"

The messenger-RNA now moves through the ribosome, and a tRNAcarrying the third amino acid (Val) binds to the next codon. Thedipeptide is then transferred to the amino acid on this thirdtRNA to form a tripeptide. This sequence of steps continues untilone of three codons is encountered: UAA, UGA, or UAG. Thesecodons give the signal for terminating the synthesis of thepolypeptide chain, and the chain is cleaved from the last tRNAresidue.

The section was then counterstained with haematoxylin and mounted with DPX.)"

Before the information in DNA can be decoded, a small portionof the DNA double helix must be uncoiled. A strand of RNA is thensynthesized that is a complementary copy of one strand of theDNA.

Versatile Services that Make Studying Easy
We write effective, thought-provoking essays from scratch
We create erudite academic research papers
We champion seasoned experts for dissertations
We make it our business to construct successful business papers
What if the quality isn’t so great?
Our writers are sourced from experts, and complete an obstacle course of testing to join our brigade. Ours is a top service in the English-speaking world.
How do I know the professor won’t find out?
Everything is confidential. So you know your student paper is wholly yours, we use CopyScape and WriteCheck to guarantee originality (never TurnItIn, which professors patrol).
What if it doesn’t meet my expectations?
Unchanged instructions afford you 10 days to request edits after our agreed due date. With 94% satisfaction, we work until your hair is comfortably cool.
Clients enjoy the breezy experience of working with us
Click to learn our proven method

Western Blot; Sample: Recombinant protein.))"


Western Blot; Sample: Recombinant protein.))"

To understand how proteins are made, we have to divide thedecoding process into two steps. DNA only stores the geneticinformation, it isn't involved in the process by which theinformation is used. The first step in protein biosynthesistherefore has to involve transcribing the information inthe DNA structure into a useful form. In a separate step, thisinformation can be translated into a sequence of aminoacids.

Western Blot; Sample: Recombinant protein.))"

When we predict the sequence of nucleotides in the RNAcomplement, we have to remember that RNA uses U where T would befound in DNA. We also have to remember that base pairing occursbetween two chains that run in opposite directions. TheRNA complement of this DNA should therefore be written asfollows.

Aminoacyl tRNA synthetase - Wikipedia

The messenger RNA now binds to a ribosome, where the messageis translated into a sequence of amino acids. The amino acidsthat are incorporated into the protein being synthesized arecarried by relatively small RNA molecules known as transferRNA, or tRNA. There are atleast 60 tRNAs, which differ slightly in their structures, ineach cell. At one end of each tRNA is a specific sequence ofthree nucleotides that can bind to the messenger RNA. At theother end is a specific amino acid. Thus, each three-nucleotidesegment of the messenger RNA molecule codes for the incorporationof a particular amino acid. The relationship between thetriplets, or codons, on the mRNA and the amino acids is shown inthe table below.

Protein Synthesis -Translation and Regulation

Escherichia coli 4-fluorotryptophan-substituted arginyl-tRNA synthetase was biosynthetically prepared and purified from a tryptophan auxotroph which could overproduce this enzyme. A method was developed to separate 4- fluorotryptophan from tryptophan and to determine accurately their contents in the 4-fluorotryptophan-containing proteins. It was confirmed that more than 95% of the tryptophan residues in the purified 4-fluorotryptophan- substituted arginyl-tRNA synthetase were replaced by 4-fluorotryptophan. Studies on the effect of the 4-fluorotryptophan replacement on properties of the enzyme showed that, when compared with the native enzyme, both the specific activity and the first-order rate constant of the fluorinated enzyme decreased by approximately 20% with just slightly higher K(m) values. CD studies, however, did not reveal any difference between the secondary structure of the native and fluorinated enzymes. In addition, thermal unfolding studies showed that the 4-fluorotryptophan replacement did not significantly affect the thermal stability of the enzyme. We may conclude that the substitution of 4-fluorotryptophan in arginyl-tRNA synthetase had no substantial effect on the structure and function of the enzyme. Finally, a preliminary study of 19F nuclear magnetic resonance spectroscopy of the fluorinated enzyme has shown promising prospect for further investigation of its structure and function with NMR.

What Is Protein Synthesis - Protein Synthesis

N2 - Escherichia coli 4-fluorotryptophan-substituted arginyl-tRNA synthetase was biosynthetically prepared and purified from a tryptophan auxotroph which could overproduce this enzyme. A method was developed to separate 4- fluorotryptophan from tryptophan and to determine accurately their contents in the 4-fluorotryptophan-containing proteins. It was confirmed that more than 95% of the tryptophan residues in the purified 4-fluorotryptophan- substituted arginyl-tRNA synthetase were replaced by 4-fluorotryptophan. Studies on the effect of the 4-fluorotryptophan replacement on properties of the enzyme showed that, when compared with the native enzyme, both the specific activity and the first-order rate constant of the fluorinated enzyme decreased by approximately 20% with just slightly higher K(m) values. CD studies, however, did not reveal any difference between the secondary structure of the native and fluorinated enzymes. In addition, thermal unfolding studies showed that the 4-fluorotryptophan replacement did not significantly affect the thermal stability of the enzyme. We may conclude that the substitution of 4-fluorotryptophan in arginyl-tRNA synthetase had no substantial effect on the structure and function of the enzyme. Finally, a preliminary study of 19F nuclear magnetic resonance spectroscopy of the fluorinated enzyme has shown promising prospect for further investigation of its structure and function with NMR.

ER stress and the unfolded protein response - …

AB - Escherichia coli 4-fluorotryptophan-substituted arginyl-tRNA synthetase was biosynthetically prepared and purified from a tryptophan auxotroph which could overproduce this enzyme. A method was developed to separate 4- fluorotryptophan from tryptophan and to determine accurately their contents in the 4-fluorotryptophan-containing proteins. It was confirmed that more than 95% of the tryptophan residues in the purified 4-fluorotryptophan- substituted arginyl-tRNA synthetase were replaced by 4-fluorotryptophan. Studies on the effect of the 4-fluorotryptophan replacement on properties of the enzyme showed that, when compared with the native enzyme, both the specific activity and the first-order rate constant of the fluorinated enzyme decreased by approximately 20% with just slightly higher K(m) values. CD studies, however, did not reveal any difference between the secondary structure of the native and fluorinated enzymes. In addition, thermal unfolding studies showed that the 4-fluorotryptophan replacement did not significantly affect the thermal stability of the enzyme. We may conclude that the substitution of 4-fluorotryptophan in arginyl-tRNA synthetase had no substantial effect on the structure and function of the enzyme. Finally, a preliminary study of 19F nuclear magnetic resonance spectroscopy of the fluorinated enzyme has shown promising prospect for further investigation of its structure and function with NMR.

89%
of clients claim significantly improved grades thanks to our work.
98%
of students agree they have more time for other things thanks to us.
Clients Speak
“I didn’t expect I’d be thanking you for actually improving my own writing, but I am. You’re like a second professor!”