Genetic data indicate that proteins containing the GGDEF domain possess diguanylate cyclase activity

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• A conserved GGDEF domain is present in numerous prokaryotic proteins, often alongside sensory-regulatory components.
• While GGDEF domains are widespread in bacterial genomes, their specific function remains experimentally uncharacterized.
• Cyclic di-GMP signaling is known to regulate cellulose synthesis in Acetobacter xylinum.

Purpose of the Study:

• To elucidate the functional role of the GGDEF domain in prokaryotic proteins.
• To investigate the enzymatic activity associated with the GGDEF domain.
• To determine if GGDEF domain proteins regulate cellulose synthase activity through cyclic di-GMP.

Main Methods:

• Genetic complementation assays were performed using genes encoding GGDEF domain proteins from three distinct bacterial species.
• The study focused on proteins where the GGDEF domain was the sole common feature.
• Enzymatic activity assays were conducted to assess diguanylate cyclase function.

Main Results:

• Genetic data confirm that the GGDEF domain is responsible for diguanylate cyclase activity.
• The activity of cellulose synthase in Rhizobium leguminosarum bv. trifolii and Agrobacterium tumefaciens is regulated by cyclic di-GMP.
• This regulation mechanism mirrors that observed in Acetobacter xylinum.

Conclusions:

• The GGDEF domain is a functional diguanylate cyclase in prokaryotes.
• Cyclic di-GMP acts as a second messenger regulating cellulose synthase in diverse bacterial species.
• This study establishes a conserved signaling pathway involving GGDEF domains and cyclic di-GMP in bacteria.