Biotin Domain

PDB file 1BDO

This structure of the biotinyl domain of Acetyl-CoA Carboxylase was solved by F. K. Athapilly & W. A. Hendrickson.

Suggested display options:

Display as cartoon with color structure.
What
secondary structure predominates in this protein?

Biotin: Select hetero-ligand (or btn), display as ball & sticks & color CPK.
Compare to the structure of biotin below.
Identify
the N of the ureido group of the biotin ring that is the site of carboxylation.

Biotin attachment:
To visualize the lysine that attaches biotin to the enzyme, select lys122, and display as ball & sticks with color CPK.
What is the significance of the long flexible arm that tethers the biotin ring to the enzyme, consisting of the combined side-chains of biotin and lysine?
The amide bond between biotin and lysine does not show in ball & sticks display, since it is a non-standard linkage. Biotin and lysine will look more connected if you display them both in spacefill.

The sequence that designates a lysine residue for attachment of biotin is highly conserved among biotin-utilizing enzymes.
What
type of amino acid is found on either side of the biotin-linked lys122?


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