Crystal Structure and Functional Studies of HP0242 from Helicobacter pylori
| Autor: | Bo-Tsang Chen, 陳柏蒼 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 HP0242 is a hypothetical protein from a human gastric pathogen, Helicobacter pylori. Here, we report the first crystal structure of HP0242 at 2.27 Å resolution were grown by the hanging drop vapor diffusion method and determined by multiwavelength anomalous dispersion (MAD) phasing. The overall structure of HP0242 folds like a musical instrument-triangle with four helices. Two monomers tightly interlock each other by Helix2 to form a dimer with extremely strong interactions, the total buried surface area of dimer is 3971 Å2. Helix2 also uses hydrophobic and hydrophilic residues to interact with Helix3 and Helix4 of another monomer, respectively. Helix2 is essential in the formation of HP0242 dimer, these interactions mentioned above stabilize the HP0242 structure. HP0242 is recognized as a dimer in solution according to the results of gel filtration and analytical ultracentrifugation. We suggest that dimer might represent the functional state for HP0242. A structure-based homology analysis with the DALI algorithm indicates that HP0242 has a novel fold. The HP0242 gene is next to the napA gene and there is a binding site for ferric-uptake regulator in upstream of napA gene. To date, none of the HP0242 and its homologues has been assigned a cellular function. Our results may shed a light on further functional studies based on the unique protein folding. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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