Methionine synthase

Methionine synthaseMethionine synthase

This page is being worked on during the Spring 2022 semester. Methionine is an amino acid our bodies require to ensure normal healthy tissue growth and repair. It is not made naturally in the body and can only be obtained from our diets first in the form of homocysteine. A lack of or deficiencies of methionine has been linked to diseases such as poor growth and birth abnormalities. Homocysteine, another amino acid most commonly found int he liver, is converted to methionine. EC: 2.1.1.13 PDB ID: 1K7Y - cobalamin, 1K98 - AdoMet complex (MetH) is a B12-dependent enzyme that methylates homocysteine, obtained from our diet, to regenerate methionine. The change from homocysteine to methionine is a methyl group. The full structure of has yet to be determined but we understand it contains 4 domains for its catalytic cycle and its reactivation cycle.

spinqualitylabelsall models B-12 dependent fragment of E. coli methionine synthase with Cobalt (in pink) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

The change from homocysteine to methionine is an SN2 reaction where the methyl group from methyltetrahydrofolate (MTHF), located on N-5, is donated. MTHF is a product of MTHFR.

This is a complex reaction as the product, tetrahydrofolate, is a poor leaving group, thus requiring a "supernucleophile" with a protein-bound B-12 vitamin Cobalamin as the methyl carrier.

Structural highlightsStructural highlights

This is a sample scene created with SAT to by Group, and another to make of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.