Arylformamidase Introduction: Difference between revisions

From MDWiki
Jump to navigationJump to search
No edit summary
No edit summary
 
(11 intermediate revisions by 4 users not shown)
Line 1: Line 1:
why it was chosen for structural determination
The structure 2PBL, as denoted by its Protein Data Bank (PDB) accession number, was determined using x-ray crystallography at the Joint Center for Structural Genomics (JCSG) (see figure 2). 2PBL heralds from ''Silicibacter sp.'' TM1040, a member of the ''Roseobacter'' clade of alpha-proteobacteria. One of the goals of the JCSG is to achieve structural coverage of a broad range of protein families by analysing homologous sequences from a variety of model organisms which includes ''Silicibacter sp''. For structural determination, the protein was expressed in ''Escherichia coli'' using a plasmid as the vector. A resolution of 1.79A was achieved with an R-value of 0.224 and an R-free value of 0.270, all of which are indiciative of a high-quality structure.


how its annotation arrived at 'arylformamidase
[[Image:Arylformamidase the whole protein.PNG|centre|framed|'''Figure 2:''' ''An overview of 2PBL exhibiting all chains: A - upper right, B - upper left, C - lower right & D - lower left. The red molecule in the chain structure represents an unknown ligand. The molecules in the middle of chains A & B and chains C & D  is a phosphate ion (PO4). The green molecule between chains B & D is a magnesium ion (Mg). ''Image generated using PDB ProteinWorkshop 1.5.'']]


information from pdb - structure details, etc... (perhaps picture)
Upon crystallisation, 2PBL formed a tetramer structure. However, structures which form upon crystalisation do not always denote the functional form of a protein which can exist as a dimer or oligomer as well. In fact, such forms may have been evolutionarily selected for to confer features such as thermostability  (Byun 2007).


paragraph on silicibacter sp tm1040 - evolutionary info (where it fits in) (diagram)
''Silicibacter sp.'' TM1040 was first isolated as part of an investigation into the role of bacteria in the physiology and toxigenesis of the dinoflagellate ''Pfiestera piscicida''. ''Silicibacter sp.'' TM1040 has been found necessary for the survival of this organism. Most interestingly, the bacteria is able to demethylate the dinoflagellate secondary metabolite dimethylsulfoniopropionate (DMSP) to methylmercaptopropionic acid (MMPA). DMSP is the major source of organic sulphur in the world’s oceans, forming a major part of the global sulphur cycle.


'Arylformamidase' heralds from Silibacter sp. TM1040, a member of the Roseobacter clade of alpha-proteobacteria. It was first isolated as part of an investigation into the role of bacteria in the physiology and toxigenesis of the dinoflagellate Pfiestera piscicida. Silicibacter sp. TM1040 has been found necessary for the survival of this organism. Most interestingly, the bacteria is able to demethylate the dinoflagellate secondary metabolite dimethylsulfoniopropionate (DMSP) to methylmercaptopropionic acid (MMPA). DMSP is the major source of organic sulphur in the world’s oceans, forming a major part of the global sulphur cycle.
A putative name 'arylformamidase' was assigned to the structure 2PBL based upon its closest mammalian homologue of the same name. It is possible that this name was assigned purely by convention and does not accurately reflect the protein's function, particularly when 2PBL is from such a distantly-related ancestral species. Arylformamidase in mammals is a protein involved in the tryptophan degradation pathway. Whether this name accurately reflects the protein's function in bacteria needs to be assessed.
 
Upon crystallisation, 2pbl formed a tetramer structure. However, structures formed upon crystalisation do not always denote the functional form of a protein which can exist as a dimer or oligomer as well. In fact, such forms may have been evolutionary selected for to confer features such as thermostability  (Byun 2007). By examining the crystal structure and … , we have attempted to deduce the functional form of 2pbl.
 
 
Structure was determined using X-ray diffraction by the Joint Center for Structural Genomics (JCSG). The organism is Silicibacter SP. TM1040 and the protein expression system is Escherichia Coli (vector type: plasmid). The resolution is 1.79 A with R-value of 0.224 and R-free value of 0.270. The closer the R values are to each other, the better the quality of the structure.


[[Arylformamidase | Return to the main page...]]
[[Arylformamidase | Return to the main page...]]

Latest revision as of 00:05, 10 June 2008

The structure 2PBL, as denoted by its Protein Data Bank (PDB) accession number, was determined using x-ray crystallography at the Joint Center for Structural Genomics (JCSG) (see figure 2). 2PBL heralds from Silicibacter sp. TM1040, a member of the Roseobacter clade of alpha-proteobacteria. One of the goals of the JCSG is to achieve structural coverage of a broad range of protein families by analysing homologous sequences from a variety of model organisms which includes Silicibacter sp. For structural determination, the protein was expressed in Escherichia coli using a plasmid as the vector. A resolution of 1.79A was achieved with an R-value of 0.224 and an R-free value of 0.270, all of which are indiciative of a high-quality structure.

Figure 2: An overview of 2PBL exhibiting all chains: A - upper right, B - upper left, C - lower right & D - lower left. The red molecule in the chain structure represents an unknown ligand. The molecules in the middle of chains A & B and chains C & D is a phosphate ion (PO4). The green molecule between chains B & D is a magnesium ion (Mg). Image generated using PDB ProteinWorkshop 1.5.

Upon crystallisation, 2PBL formed a tetramer structure. However, structures which form upon crystalisation do not always denote the functional form of a protein which can exist as a dimer or oligomer as well. In fact, such forms may have been evolutionarily selected for to confer features such as thermostability (Byun 2007).

Silicibacter sp. TM1040 was first isolated as part of an investigation into the role of bacteria in the physiology and toxigenesis of the dinoflagellate Pfiestera piscicida. Silicibacter sp. TM1040 has been found necessary for the survival of this organism. Most interestingly, the bacteria is able to demethylate the dinoflagellate secondary metabolite dimethylsulfoniopropionate (DMSP) to methylmercaptopropionic acid (MMPA). DMSP is the major source of organic sulphur in the world’s oceans, forming a major part of the global sulphur cycle.

A putative name 'arylformamidase' was assigned to the structure 2PBL based upon its closest mammalian homologue of the same name. It is possible that this name was assigned purely by convention and does not accurately reflect the protein's function, particularly when 2PBL is from such a distantly-related ancestral species. Arylformamidase in mammals is a protein involved in the tryptophan degradation pathway. Whether this name accurately reflects the protein's function in bacteria needs to be assessed.

Return to the main page...