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Expression, purification and crystallization of Dpr, a ferritin-like protein from the Gram-positive
Sauli Haataja1, Anni Penttinen, Arto T Pulliainen
1Department of Medical Biochemistry, University of Turku, Turku 20520, Finland.
Abstract:
Ferritin-like proteins form a novel family of bacterial proteins with diverse functions, such as DNA binding, iron storage and cell activation. A common structural feature of these proteins is their ability to form spherical dodecamers. Dpr is a ferritin-like protein from the Gram-positive bacterium Streptococcus suis. Full-length and truncated Dpr were expressed and purified as 6xHis-tag fusion proteins. Crystals of truncated Dpr suitable for X-ray diffraction analysis were obtained after the removal of the N-terminal affinity tag by thrombin cleavage. A complete data set to 2.3 A resolution was collected using synchrotron radiation. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 104.3, b = 137.6, c = 142.1 A and 12 molecules in the asymmetric unit.
Insights
This study characterizes Dpr, a novel ferritin-like protein from Streptococcus suis. Researchers determined its crystal structure, revealing its dodecameric assembly and potential functions in bacterial processes.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Ferritin-like proteins are a diverse bacterial protein family with functions including DNA binding and iron storage.
- These proteins commonly assemble into spherical dodecamers.
- Dpr is a specific ferritin-like protein found in Streptococcus suis.
Purpose of the Study:
- To express and purify Dpr, a ferritin-like protein from Streptococcus suis.
- To determine the crystal structure of truncated Dpr.
- To understand the structural basis of Dpr function.
Main Methods:
- Full-length and truncated Dpr were expressed and purified as 6xHis-tag fusion proteins.
- Crystallization of truncated Dpr was achieved after affinity tag removal.
- X-ray diffraction data were collected to 2.3 Å resolution using synchrotron radiation.
Main Results:
- Crystals of truncated Dpr were obtained and belonged to the orthorhombic space group P2(1)2(1)2(1).
- Unit-cell parameters were determined as a = 104.3, b = 137.6, c = 142.1 Å.
- Twelve Dpr molecules were found in the asymmetric unit, indicating dodecameric assembly.
Conclusions:
- The crystal structure of truncated Dpr from Streptococcus suis was determined.
- The results provide insights into the structural organization of Dpr.
- This structural information can aid in understanding the diverse functions of ferritin-like proteins in bacteria.