Structural basis for cytokinin production by LOG from Corynebacterium glutamicum

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Cytokinin production is crucial for plant growth, mediated by enzymes like "Lonely Guy" (LOG).
• The bacterial protein Cg2612 from Corynebacterium glutamicum was misannotated as a LDC, despite lacking this enzyme and showing similarity to LOG proteins.

Purpose of the Study:

• To elucidate the true function and structure of the Cg2612 protein from C. glutamicum.
• To determine if Cg2612 possesses LDC or LOG activity.

Main Methods:

• X-ray crystallography was used to determine the 3D structure of Cg2612 at 2.3 Å resolution.
• Biochemical assays were performed to assess the enzymatic activity of Cg2612.

Main Results:

• Cg2612 functions as a dimer with structural similarity to known LOG enzymes from various organisms.
• Biochemical studies confirmed phosphoribohydrolase activity and ruled out LDC activity for Cg2612.
• The prenyl-binding site of Cg2612 (CgLOG) showed similarities to plant and fungal LOGs, but differences from a bacterial MmLOG.

Conclusions:

• Cg2612 is a functional LOG enzyme, not an LDC, involved in cytokinin production.
• The findings provide structural and functional insights into LOG-like proteins in microorganisms.