Note that because of processes such as the post-translational modifications to proteins we still need protein sequencing and I believe that we currently rely too heavily on DNA sequencing. The first part of the animation shows amino acids combining to produce a polypeptide chain, the primary structure of a protein. This is because it is now much easier to sequence DNA. Instead, since it has been worked out (mostly) how DNA codes for protein, we usually infer the protein sequence from the DNA sequence. Alternatively, click on the launch icon to open the advanced (full feature) version of iCn3D, NCBI's web-based 3D structure viewer, in a separate window. Scroll to the molecular graphic section and click on the spin icon to load an interactive view of the structure within the web page. However, it is now relatively rare to directly determine protein sequence! Enter the PDB code in the search box and press the Go button. The very first protein sequence (bovine insulin) was determined by Fredrick Sanger in 1951-2 (note that this was more than a decade before the first nucleotide sequence). There are many different techniques for directly determining protein sequences - this wikipedia article is a decent introduction: There are also methods that have been developed to remove amino acids one at a time.īy combining theses techniques it is possible to directly determine protein sequences. The primary structure of a protein refers to the order of amino acid residues in the polypeptide chain of the protein. In order to make a protein, you must first make a copy of the DNA. This is a great question, but actually quite complicated so I'm not going to try to give a complete answer - I have given some useful links below if you wish to learn more.Įach amino acid has unique chemical properties that can be used to tell them apart. The primary structure of a protein is encoded in your DNA. Protein structure - This lecture explains about the protein structure hierarchy including primary, secondary, tertiary structures of protein.
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