Difference between revisions of "Gaucher Disease: Task 09 - Lab Journal"

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(1. Choose a structure to work with)
(1. Choose a structure to work with)
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|[http://www.pdb.org/pdb/files/1OGS.pdb 1OGS] || 2.0 || A/B || 40-536 (92.7%) || - || '''1-497''' || 0.195 || 0.230 || 4.6 || 100
 
|[http://www.pdb.org/pdb/files/1OGS.pdb 1OGS] || 2.0 || A/B || 40-536 (92.7%) || - || '''1-497''' || 0.195 || 0.230 || 4.6 || 100
 
|}
 
|}
<center><small>'''<caption>''' Comparison of the resolution top five PDB structures according to different other criteria.</caption></small></center>
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<center><small>'''<caption>''' Comparison of the resolution top six PDB structures according to different other criteria.</caption></small></center>
 
</figtable>
 
</figtable>
   

Revision as of 17:43, 29 August 2013

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This page is under construction.

Preparation

1. Choose a structure to work with

In the former tasks, we worked with the reference structure 1OGS, because it has no gaps - except for an offset of 39 residues at the N terminus that all structures for our protein P04062 referenced in UniProt have - and has a pretty low resolution of 2.0 Å. However, there are five other structures with a lower or equal resolution (all resolved using the X-ray diffraction method). We compared 1OGS and those five structures for the resolution, coverage and gaps, R-factor, R-free and pH-value at which the structure was resolved in order to choose the best structure suiting the requirements of this task (<xr id="structure_choice"/>).

<figtable id="structure_choice">

PDB-ID Resolution (Å) Chain Covered residues (UniProt seq.) Missing residues (ATOM seq.) Covered residues (ATOM seq.) R-Value(obs.) R-Free pH Temperature (K)
2NT0 1.79 A/B/C/D 40-536 (92.7%) - 1-497 0.181 0.215 4.5 100
3GXI 1.84 A/B/C/D 40-536 (92.7%) - 1-497 0.193 0.231 5.5 NULL
2V3F 1.95 A/B 40-536 (92.7%) A: 29-31, (499-503), B: (-1-0), 27-32, (498-503) A: -1-28, 32-498, B: 1-26, 33-497 0.154 0.196 6.5 100
2V3D 1.96 A/B 40-536 (92.7%) A: 28-31, (499-503), B: (-1-0), (498-503) A: -1-27, 32-498, B: 1-497 0.157 0.208 6.5 100
2V3E 2.0 A/B 40-536 (92.7%) A: 31, (498-503), B: (-1), (498-503) A: -1-30, 32-497, B: 0-497 0.163 0.220 7.5 100
1OGS 2.0 A/B 40-536 (92.7%) - 1-497 0.195 0.230 4.6 100
Comparison of the resolution top six PDB structures according to different other criteria.

</figtable>

In all the investigated structures residues numbered 1-497 are native and correspond to the positions 40-536 in the UniProt sequence P04062. In some of the structures, like in 2V3E, two residues were added at the beginning (EF, positions -1, 0) and six residues at the end (LLVDTM, positions 498-503). If these "axillary" residues are missing in the resolved structure, we can ignore it.

The structures 2NT0, 3GXI and our familiar reference structure, 1OGS, have no missing residues and the first two candidates have the lowest resolutions (1.79 and 1.84, respectively). However, the pH-values, at which they were resolved, are too low (4.5, 5.5 and 4.6, respectively).

The structure 2V3F seems to be a good choice, because it compromises between the pH-value (pH=6.5 is near to the physiological value of 7.4) and low resolution (1.95 Å). Moreover, it has the lowest R-value (0.154) and R-free (0.196). However, there are some missing residues (29-31 in chain A and 27-32 in chain B).

The candidate 2V3D has similar values, but it also has gaps in chain A (28-31). We could have used the chain B, thought.

A structure candidate with the same resolution as 1OGS and a neutral pH of 7.5 is 2V3E. It has only one missing residue in chain A (31) and none native residues are missing in chain B. As it is the lowest resolution structure resolved at a physiological pH-value and the chain B has no gaps, we choose 2V3E, chain B for this task.

2. Visualise the mutations you want to work with

3. Create mutated structures

Energy comparisons

foldX

Minimise

Gromacs (optional task for those who love MD!)

Sources

PDB R-value and R-free