Modeling studies with Helicobacter pylori octaprenyl pyrophosphate synthase reveal the enzymatic mechanism of trans-prenyltransferases

• Published in: The international journal of biochemistry & cell biology 2012-12, Vol.44 (12), p.2116-2123
• Main Authors: Zhang, Jinyong, Zhang, Xiaoli, Zhang, Rui, Wu, Chao, Guo, Ying, Mao, Xuhu, Guo, Gang, Zhang, Ying, Wang, Da-Cheng, Li, Defeng, Zou, Quanming
• Format: Article
• Language: English
• Subjects: Alkyl and Aryl Transferases - chemistry; Alkyl and Aryl Transferases - genetics; Amino Acid Sequence; Amino Acid Substitution; bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; binding sites; biochemistry; Catalytic Domain; Catalytic mechanism; cell biology; Conserved Sequence; crystal structure; Crystallography, X-Ray; drugs; Farnesyl pyrophosphate; Helicobacter pylori; Helicobacter pylori - enzymology; Hemiterpenes - chemistry; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Isopentenyl pyrophosphate; magnesium; Molecular Docking Simulation; Molecular Sequence Data; Mutagenesis, Site-Directed; Octaprenyl pyrophosphate synthase; Organophosphorus Compounds - chemistry; Polyisoprenyl Phosphates - chemistry; Protein Binding; Protein Interaction Domains and Motifs; Protein Structure, Secondary; pyrophosphates; Sesquiterpenes - chemistry; Structure
• ISSN: 1357-2725; 1878-5875
• DOI: 10.1016/j.biocel.2012.09.002

Octaprenyl pyrophosphate synthase (OPPs), an enzyme belonging to the trans-prenyltransferases family, is involved in the synthesis of C40 octaprenyl pyrophosphate (OPP) by reacting farnesyl pyrophosphate (FPP) with five isopentenyl pyrophosphates (IPP). It has been reported that OPPs is essential for bacteria's normal growth and is a potential target for novel antibacterial drug design. Here we report the crystal structure of OPPs from Helicobacter pylori, determined by MAD method at 2.8Å resolution and refined to 2.0Å resolution. The substrate IPP was docked into HpOPPs structure and residues involved in IPP recognition were identified. The other substrate FPP, the intermediate GGPP and a nitrogen-containing bisphosphonate drug were also modeled into the structure. The resulting model shed some lights on the enzymatic mechanism, including (1) residues Arg87, Lys36 and Arg39 are essential for IPP binding; (2) residues Lys162, Lys224 and Gln197 are involved in FPP binding; (3) the second DDXXD motif may involve in FPP binding by Mg2+ mediated interactions; (4) Leu127 is probably involved in product chain length determination in HpOPPs and (5) the intermediate products such as GGPP need a rearrange to occupy the binding site of FPP and then IPP is reloaded. Our results also indicate that the nitrogen-containing bisphosphonate drugs are potential inhibitors of FPPs and other trans-prenyltransferases aiming at blocking the binding of FPP.