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3

There are two things at play here and you need to mentally separate them. When seen as molecules, all amino acids are polar to at least some degree. Most of them are very polar, especially when compared to other organic molecules. This is (obviously) due to the carboxylic acid and amino groups both of which are very polar functional groups and both of which ...


6

This answer is for ChemDoodle, but I think you can import SVG files into ChemDraw as well. Just take an SVG image of an alpha helix and copy and paste it into ChemDoodle. Or go to File -> Insert Image and select the SVG file from your computer. It doesn't have to be SVG, but they have advantages with scaling. Made this using this File from Wikipedia, but ...


12

I use ChemDraw Professional 19.1.1.32. If you follow File>Open Templates>Advanced BioDraw, you will find the black helix that I have reoriented from horizontal to vertical. The red helix was enlarged and colored red. I hope this is of help.


11

This illustration may be a combination of two images, or simply a program I don't know about. However, there are many (3D) protein visualisation programs that can show alpha-helices such as PyMol, VMD or Yasara. Here you can ray-trace the image (i.e. transparent background) and then combine the illustration with something else, e.g. an illustration from ...


1

Rather than worry about reducing agents in the HPLC column, why not oxidize your cysteines with Ellman's Reagent and reduce them after purification? As long as you use an excess of Ellman's Reagent, it should completely oxidize the thiols and prevent disulfide bond formation.


2

This might relate to the concept of 'capping' alpha-helices, where the placement of beneficial charges at either end of a helix is shown to increase the overall stability of the protein. See the article1 published in Nature. In general, by introducing preferential charges at the ends of alpha-helices you stabilize the inherent dipole moment created by the ...


3

I dont know about HPLC column tolerance to various reducing agents, this would need to be checked. However, in biochemistry we routinely add reducing agents to avoid disulphide-bridge formation in the proteins. Overall there are three main reducing agents used, to avoid this problem. The choice of which one to use depends on your needs. They include: TCEP: ...


1

Actually DNP-labeling of amino groups was first introduced in 1923 when 2,4-dinitrochlorobenzene (DNCB) was used for the identification of the terminal groups of a partial hydrolysate of silk fibroin (Ref.1). Then, Sanger has introduced 1-fluoro-2,4-dinitrobenzene (DNFB) in 1945, which bears his name, the Sanger’s reagent. DNFB was first used to detect free ...


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