Molecular Playground/OmpG: Difference between revisions
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==Structural Features of OmpG== | ==Structural Features of OmpG== | ||
OmpG is a 14-stranded beta-barrel and in contrast to most porins, appears to function as a monomer.[1] The central pore of OmpG is wider than other E. coli porins and it is speculated that it may form a non-specific channel for the passive transport of large oligosaccharides.[1] OmpG adopts two main conformations: open and closed. | OmpG is a 14-stranded beta-barrel and in contrast to most porins, appears to function as a monomer.[1] The central pore of OmpG is wider than other E. coli porins and it is speculated that it may form a non-specific channel for the passive transport of large oligosaccharides.[1] OmpG adopts two main conformations: open and closed which is termed gating. | ||
[[Image: | [[Image:Open and closed OmpG.jpg|left|thumb|]] | ||
At neutral pH the porin is mainly in an open conformation, with periodic closures. However at a more acidic pH the closed conformation is becomes dominant. This fluctuation between open and closed is a result of OmpG's flexible loop 6 (highlighted in red), which folds across the channel blocking the pore opening. The rearrangement of loop 6 appears to be triggered by a pair of histidine residues, which repel each other at acidic pH, resulting in the breakage of neighbouring H-bonds and a lengthening of loop 6 from 10 to 17 residues[2,3]. <scene name='User:Christina_Chisholm/Sandbox_1/Greenwoselection_ompg/3'></scene> | At neutral pH the porin is mainly in an open conformation, with periodic closures. However at a more acidic pH the closed conformation is becomes dominant. This fluctuation between open and closed is a result of OmpG's flexible loop 6 (highlighted in red), which folds across the channel blocking the pore opening. The rearrangement of loop 6 appears to be triggered by a pair of histidine residues, which repel each other at acidic pH, resulting in the breakage of neighbouring H-bonds and a lengthening of loop 6 from 10 to 17 residues[2,3]. <scene name='User:Christina_Chisholm/Sandbox_1/Greenwoselection_ompg/3'></scene> | ||
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[http://en.wikipedia.org/wiki/Outer_membrane_protein_G]. | [http://en.wikipedia.org/wiki/Outer_membrane_protein_G]. | ||
The loop environment of OmpG carries a net negative charge. This highly negative character may be implicated in the gating behavior of OmpG. If we can gain a deeper understanding of | The loop environment of OmpG carries a net negative charge. This highly negative character may be implicated in the gating behavior of OmpG. If we can gain a deeper understanding of the individual loop behavior in the overall gating, we could use this knowledge to tune it for specific detection of a wide variety of target analytes. | ||
[[Image:OmpG_top_down_of_net_negative_loop_region.png|left|thumb|]] | [[Image:OmpG_top_down_of_net_negative_loop_region.png|left|thumb|]] | ||
