Open conformation Shown in purple are residues 1-19 and 241-427 which comprise domain 1 and in yellow are residues 20-240 which comprise domain 2. N-terminal region 1-19 appears in cyan. Note two crossover segments that link the domains.

Closed conformation Shown in purple are residues 1-19 and 241-427 which comprise domain 1 and in yellow are residues 20-240 which comprise domain 2. N-terminal region 1-19 appears in cyan. Secondary structures in magenta (alpha helices) and yellow (beta strands) with bound shikimate-3-phosphate (S3P) and glyphosate in active site.

Structural folds EPSP synthase is made up of two domains, each with three separate ßaßaßß-folding units. N- and C-terminal fragments are in green. Two strands that are not directly connected to other secondary structures within their own folding units are rendered in cyan.

Active site Active site is nestled in between domains 1 and 2 which close upon substrate binding. Shikimate-3-phosphate (S3P) is in green, and glypohsate in blue. Conserved residues are shown and atoms within 3 Angstroms of glyphosate and S3P are rendered in cpk.

Mechanism Proposed mechanism of Schönbrunn et al (1). Shown here is glyphosate representing the structurally similar substrate, PEP. His385 donates a proton to Glu341 which then protonates the methylene group of PEP. Asp313 abstracts a proton from S3P hydroxyl which then attacks the oxocarbenium ion of PEP. Lys 22 protonates and releases the phosphoryl group.