Direct visualization of critical hydrogen atoms in a pyridoxal 5'-phosphate enzyme.

ABSTRACT: Enzymes dependent on pyridoxal 5'-phosphate (PLP, the active form of vitamin B₆) perform a myriad of diverse chemical transformations. They promote various reactions by modulating the electronic states of PLP through weak interactions in the active site. Neutron crystallography has the unique ability of visualizing the nuclear positions of hydrogen atoms in macromolecules. Here we present a room-temperature neutron structure of a homodimeric PLP-dependent enzyme, aspartate aminotransferase, which was reacted in situ with α-methylaspartate. In one monomer, the PLP remained as an internal aldimine with a deprotonated Schiff base. In the second monomer, the external aldimine formed with the substrate analog. We observe a deuterium equidistant between the Schiff base and the C-termi

SUBMITTER: Dajnowicz S 

PROVIDER: S-EPMC5643538 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature