Molecular oxygen regulates the enzymatic activity of a heme-containing diguanylate cyclase (HemDGC) for the synthesis of cyclic di-GMP

作者：Sawai Hitomi; Yoshioka Shiro; Uchida Takeshi; Hyodo Mamoru; Hayakawa Yoshihiro; Ishimori Koichiro; Aono Shigetoshi^*

来源：Biochimica et Biophysica Acta-Proteins and Proteomics, 2010, 1804(1): 166-172.

DOI：10.1016/j.bbapap.2009.09.028

• Diguanylate cyclase
• Oxygen sensor protein
• Globin-coupled sensor
• Heme
• Bacterial second messenger

We have studied the structural and enzymatic properties of a diguanylate cyclase from an obligatory anaerobic bacterium Desulfotalea psychrophila, which consists of the N-terminal sensor domain and the C-terminal diguanylate cyclase domain. The sensor domain shows an amino acid sequence homology and spectroscopic properties similar to those of the sensor domains of the globin-coupled sensor proteins containing a protoheme. This heme-containing diguanylate cyclase catalyzes the formation of cyclic di-GMP from GTP only when the heme in the sensor domain binds molecular oxygen. When the heme is in the ferric, deoxy, CO-bound, or NO-bound forms, no enzymatic activity is observed. Resonance Raman spectroscopy reveals that Tyr55 forms a hydrogen bond with the heme-bound O(2), but not with CO. Instead, Gln81 interacts with the heme-bound CO. These differences of a hydrogen bonding network will play a crucial role for the selective O(2) sensing responsible for the regulation of the enzymatic activity.

• 出版日期2010-1