Studying how cyclic β-1,2-glucan synthase forms cyclization mechanisms at Tokyo University of Science.
In a groundbreaking study conducted by a team of researchers from Tokyo University of Science, the intricate mechanism underlying the cyclization process catalyzed by the cyclization domain of cyclic β-1,2-glucan synthase (CGS) from Thermoanaerobacter italicus has been unveiled. Cyclic β-1,2-glucans (CβGs) play a crucial role in various bacterial infections and symbiotic relationships, and their biosynthesis is orchestrated by CGS, an enzyme responsible for converting linear β-1,2-glucan (LβG) into cyclic structures.
The research, led by Assistant Professor Nobukiyo Tanaka, delved into the functional and structural analysis of the CGS cyclization domain from Thermoanaerobacter italicus. By expressing the cyclization domain TiCGSCy as a recombinant enzyme in Escherichia coli, the team successfully characterized its activity on LβGs. Through nuclear magnetic resonance spectroscopy, the researchers detected the production of CβGs by TiCGSCy, marking a significant milestone in understanding the catalytic process.
Further investigations unveiled that TiCGSCy exhibits transglycosylation without hydrolysis, requiring substrates of at least hexasaccharide length for optimal activity. The team also proposed that TiCGSCy operates via an anomer-retaining mechanism, generating products with the same anomer as the substrate. Structural analysis using X-ray crystallography revealed similarities between TiCGSCy and other glucanases, despite low amino acid sequence homology.
The researchers pinpointed key catalytic residues in TiCGSCy, with E1356 acting as a general acid and E1442 as a nucleophile during the cyclization process. The detailed reaction mechanism elucidated how these residues facilitate the formation of glycosyl-enzyme intermediates, leading to the production of cyclic β-1,2-glucans. The team's findings not only shed light on the unique mechanism of TiCGSCy but also classified this enzyme into a novel family of glycoside hydrolases, GH189.
By uncovering the essential residues crucial for cyclization, the study paves the way for identifying enzymes with enhanced cyclizing activity and stability. This newfound knowledge holds promise for future research endeavors aimed at exploring CGS inhibition strategies, potentially offering novel therapeutic avenues for combating bacterial diseases and disrupting symbiotic relationships.
In summary, the researchers' meticulous investigation has unraveled the intricate cyclization mechanism of CGS, providing valuable insights into the biosynthesis of cyclic β-1,2-glucans and laying the foundation for further advancements in enzyme engineering and drug development in the field of bacterial infections and symbiosis.
Source: https://www.eurekalert.org/news-releases/1036590
The research, led by Assistant Professor Nobukiyo Tanaka, delved into the functional and structural analysis of the CGS cyclization domain from Thermoanaerobacter italicus. By expressing the cyclization domain TiCGSCy as a recombinant enzyme in Escherichia coli, the team successfully characterized its activity on LβGs. Through nuclear magnetic resonance spectroscopy, the researchers detected the production of CβGs by TiCGSCy, marking a significant milestone in understanding the catalytic process.
Further investigations unveiled that TiCGSCy exhibits transglycosylation without hydrolysis, requiring substrates of at least hexasaccharide length for optimal activity. The team also proposed that TiCGSCy operates via an anomer-retaining mechanism, generating products with the same anomer as the substrate. Structural analysis using X-ray crystallography revealed similarities between TiCGSCy and other glucanases, despite low amino acid sequence homology.
The researchers pinpointed key catalytic residues in TiCGSCy, with E1356 acting as a general acid and E1442 as a nucleophile during the cyclization process. The detailed reaction mechanism elucidated how these residues facilitate the formation of glycosyl-enzyme intermediates, leading to the production of cyclic β-1,2-glucans. The team's findings not only shed light on the unique mechanism of TiCGSCy but also classified this enzyme into a novel family of glycoside hydrolases, GH189.
By uncovering the essential residues crucial for cyclization, the study paves the way for identifying enzymes with enhanced cyclizing activity and stability. This newfound knowledge holds promise for future research endeavors aimed at exploring CGS inhibition strategies, potentially offering novel therapeutic avenues for combating bacterial diseases and disrupting symbiotic relationships.
In summary, the researchers' meticulous investigation has unraveled the intricate cyclization mechanism of CGS, providing valuable insights into the biosynthesis of cyclic β-1,2-glucans and laying the foundation for further advancements in enzyme engineering and drug development in the field of bacterial infections and symbiosis.
Source: https://www.eurekalert.org/news-releases/1036590
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