Transaminase - PLP

PDB file 1ARS

This file depicts E. Coli Transaminase (Aspartate Aminotransferase), with prosthetic group pyridoxal-5'-phosphate (PLP) in Schiff base linkage to the e-amino group of an enzyme lysine. This structure was solved by A. Okamoto, T. Higuchi, & K. Hirotsu, in 1993.

Suggested display options:

Start with the protein in wireframe, and color chain. 
Select hetero-ligand, color CPK and display as ball & stick, to visualize the pyridoxal phosphate (PLP). 
Use the command line to select lys258, display as ball & stick, and color CPK to visualize the lysine residue in Schiff base linkage to PLP.

Identify the lysine N and PLP C involved in this bond.
Identify the positively charged ring N of PLP, that is proposed to act as an electron sink promoting catalysis.

Try to identify the following:
(1) The conserved aspartate whose side-chain carboxyl forms a salt bridge to the positively charged N of the PLP pyridine ring.
(2) The positively charged amino acid side chain that forms part of the binding site for the phosphate moiety of PLP.

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