Structure And Function Study Of Gluconate 5-dehydrogenase From Streptococcus Suis Serotype 2

Streptococcus suis is an important zoonotic pathogen, which caused great economic loss in the pig industry worldwide every year. It attached more importance especially after it was recorded that human meningitis was caused by Streptococcus suis in Denmark in 1968. So far it has caused more than 200 cases of severe human infection worldwide.Streptococcus suis can be divided into 35 serotypes on basis of polysaccharide film. Streptococcus suis serotype 2 (SS2) is a serotype that human and pigs were frequently infected. Genome sequenceing of Streptococcus suis 2 has been completed. Gene code 05SSU1225 belongs to short-chain dehydrogenase family, namely gluconate-5-dehydrogenase (Ga5DH). Ga5DH can catalyze gluconate and 5-keto gluconate between the reversible reaction, which regulate the body's carbon and renewable NADP to maintain balance of the body's metabolism. The metabolism of sugar acid plays a vital role in pig Streptococcus colonizing in the host tissue.When the sources of the sugar acid are limited in the host organizations, The metabolism of D-gluconate will directly determine the survival and proliferation of Streptococcus suis. Understanding the mechanism details of the metabolism of the sugar acid, such as the structure of the sugar-acid enzyme and the processes of the metabolism plays key roles in the drug design for the prevention and treatment of streptococcal infection diseases.In this study, Ga5DH (Gluconate 5–dehydrogenase) from Streptococcus suis 2 was initially identified by bioinformatics methods. Encoding protein was obtained in vitro using recombinant gene technology and expressed in E. coli bacteria. Crystals suitable for X-ray diffraction was obtaind by screening and optimizing, The X-ray diffraction data was obtained and then processed by some related softwares. The fine three dimensional structures were solved, Reaction mechanism of Ga5DH was analysed as a carbon source based on the structure, which reveals that the role of enzymes in the body mechanism, and provides a theoretical basis for drug design, as well as helps to find more effective anti-drug Streptococcus suis disease...