Identification of the allosteric site for neutral amino acids in the maize C₄ isozyme of phosphoenolpyruvate carboxylase: The critical role of Ser-100.

ABSTRACT: The isozymes of photosynthetic phosphoenolpyruvate carboxylase from C₄ plants (PEPC-C₄) play a critical role in their atmospheric CO₂ assimilation and productivity. They are allosterically activated by phosphorylated trioses or hexoses, such as d-glucose 6-phosphate, and inhibited by l-malate or l-aspartate. Additionally, PEPC-C₄ isozymes from grasses are activated by glycine, serine, or alanine, but the allosteric site for these compounds remains unknown. Here, we report a new crystal structure of the isozyme from Zea mays (ZmPEPC-C₄) with glycine bound at the monomer-monomer interfaces of the two dimers of the tetramer, making interactions with residues of both monomers. This binding site is close to, but different from

SUBMITTER: Gonzalez-Segura L 

PROVIDER: S-EPMC6028945 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature