Protein display options
...
ball and stick ...
wireframe ...
trace ...
cartoon ...
spacefill ...
Primary structure
Colour each amino acid ....
Show residue numbers ....
Show residue names ...
Remove labels & restore default colours
Secondary structure
Cartoon format coloured by structure - α helices pinkish red, other helices purple/dark blue, β sheets gold
Note especially the central
barrel-shaped section through which the substrate presumably passes as it is fed into the active site.
Show /
hide main chain H bonds
....
Molecular surface off
. . .
Show /
hide sidechain H bonds
Active site
Rotate molecule to look down into active site
The following amino acid residues have been identified (reference below) as contributing to the conversion of glucose polysaccharides (amylose, starch) into disacccharides (maltose). Interestingly, they all have acidic side-chains (aspartic acid and glutamic acid).
Show /
hide ASP 197, GLU 233 & ASP300 at active site (white spacefill)
Show /
hide enzyme co-factors: calcium (orange) and chloride (turquoise) ions
Show /
hide glucose dimer (maltose - the product of starch hydrolysis) red and grey