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biogenesis essential. Study found that many Gram-positive bacteria (such as Streptococcus pneumoniae, S.pneumoniae), negative bacteria (such as Salmonella typhimurium, Salmonella typhimurium) and fungi (Candida albicans, Candida albicans), etc. If you can not get enough from the outside of the yellow Su (flavin) requires its own synthesis of riboflavin (vitamin B12, riboflavin) in order to maintain cell survival and proliferation [4,5,6]. DHBPs (3,4-Dihydroxy-2-butanone-4-phosphate synthase), 3,4 - dihydroxy-2 - butanone -4 - phosphate synthase, a key enzyme for the biosynthesis of riboflavin [7]. In the presence of magnesium ions DHBPs 5 - ribulose (ribulose-5-phosphate, Ru5P) decomposition of 3,4 - dihydroxy-2 - butanone -4 - acid (3,4-dihydroxy-2- butanone-4-phosphate, DHBP) and formic acid (formate). DHBP generated riboflavin synthesis necessary for the raw material [2]. Therefore, if the activity can be suppressed DHBPs, it may block the bacterial synthesis of riboflavin, thereby inhibiting bacterial survival and proliferation. No synthetic riboflavin related human enzymes obtained directly from food to survive needs. Therefore bacteria involved in the biosynthesis of riboflavin enzymes become antibacterial drug target sites, and its three-dimensional structure to get the design and development of a new generation of antimicrobial agents promising to provide important structural model [7,8]. Therefore expected to become the next generation of antibiotics role DHBPs target proteins. Streptococcus pneumoniae resistance against the world more and more serious problems, develop innovative structure-based antibiotics imminent. This issue through sources DHBPs against Streptococcus pneumoniae structure analysis, the purpose is for potential new antibiotics or vaccines provide a theoretical basis. Cloning, expression, purification DHBPs protein and crystallized by a vapor diffusion method Streptococcus pneumoniae DHBPs crystals obtained using the house X-ray source (rotating anode) better resolution diffraction data collected; to Protein Data Bank (PDB) in order to Candida albicans The DHBPs (PDB code 10.2210) the A chain of amino acid residues 1-200 as a model, using the molecular replacement method (Molecular Replacement, MR) to obtain a three-dimensional crystal structure model DHBPs. And received a resolution 2.21-2.20?'s Data, using molecular replacement method parse out DJHBPs three-dimensional structure, and its amendments. Amended DHBPs dimensional spatial structure (Rfactor = 5.5%, Rfree = 34.5%, PDB code). Through structural analysis found: DHBPs other species with known sources DHBPs molecular structure similar to the structure is evolutionarily conserved protein. In this study, the use of gel chromatography experiments confirmed: DHBPs in solution to form dimers and monomers exist in two forms, with the crystal dimer two monomers combine to form molecular packing way is consistent; through protein structure, sequence analysis showed that: the substrate binding site in DHBPs dimer binding sites, a plurality of amino acids involved include: Arg 139, Thr143, and His142 other Ru5P directly involved in the binding of phosphate groups; Glu30, Asp32 , Cys57, Glu163, Thr96 (B molecules), His125 (B molecule) and Asp90 (B molecule) and so directly involved with Ru5P ribulose groups combined, and Leu55 and Phe85 provides a combination of enzyme and substrate hydrophobic environment , is based on three-dimensional structure of the new antibiotic study provides a theoretical basis.
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