Amino acid sequence

[kikkid]

Could someone please tell me what the easiest way to change an amino acid sequence is? (In an experimental situation)

[mith]

Cut it up

[kikkid]

Thank you! Once it is cut up (forgiveme for sounding ignorant) how is the new sequence formed? I mean, won't the amino acids just go right back to their original sequence unless something else is altered?

[mith]

Well, think of it this way, if you drop a cup, it'll shatter into pieces; will the pieces ever come back together and form a cup?

You're adding water to break a peptide bond.


Another way to change the AA sequence is to change the DNA template from which it is made.

[dna89]

yup, mith is right. site directed mutagenesis.

[Jessy Springfield]

Another way to change the AA sequence is to change the DNA template from which it is made.

So do you have any information on the processes in which this is performed?

[mith]

umm, DNA mutation?

[Jessy Springfield]

umm, DNA mutation?

yes, but by manipulation of specific regions?

[mith]

Well you could randomly blast UV rays at it till some sort of mutation occurs in that region, otherwise you could try using a virus to integrate itself into that region.

[victor]

Well, I think I've ever heard about the process in the seminar that I attended. The professor who presented his paper said that to make a peptide (of course not a protein, it's too long) with a desirable sequence from a protein, first we can hydrolize the peptide bond of the constituting protein into the corresponding amino-acids.
Next we can purify these amino-acids and bind them again one by one using the help of cellulose membrane and the Fmoc chemistry agent. The process is binding the amino-acid that you want into the cellulose membrane and then slowly add it one by one using an "activated amino-acid", an amino-acid which has been bound into the Fmoc chemistry agent. This Fmoc-bound amino acid will have an activated C-terminus, so then it will react with the amino group with the first amino-acid which is bound within the cellulose. This process is repeated again and again until we get the whole sequenced peptide as we want

Here is the schematic process:

hope you like it

[mith]

a synthetic ribosome lol

[victor]

hope they can do that
Usually they (the professor and the team) only make a peptide which is consisted about 5 amino-acids, but the process is automated so they can get about 1 chip/day (1 chip is consisted about 8000 peptide molecules). They also found that these short peptides ara powerful agent to reduce cancer and they have tested to the leukemia and it works