NalP: Difference between revisions

The alpha helix within the beta barrel is a major obstruction, which allows for regulated channel. The alpha helix corresponds to the .15nS opening that is observed and without this obstruction a 1.3nS open pore is created which allows for a much more free flowing pore. This is found to be an infrequent occurrence that could be caused by a detergent and high salt concentration. Due to this being the more infrequent type of pore it can be deduced that the internal alpha helix is what is found in vivo. The alpha helix is found internally on the N-terminus side of the protein and extends from <scene name='Translocator_Domain_of_the_Autotransporter_NalP_within_Neisseria_meningitidis/N-terminus/1'>N-terminus facing the extracellular space</scene>, colored orange, leading inward toward the cytoplasm that then turns into a beta pleated sheet that creates the barrel shape. This structure is consistent with the final stage of translocation, which allows for proteins to be released into the extracellular space. The alpha helix is charged almost solely on one side. This charged side of the alpha helix is able to interact with an axial line of charged side chains that point inward from the beta barrel. Through seven salt bridges, as well as 16 hydrogen bonds and several van der Waals contacts, the alpha helix is able to interact with one side of the beta barrel.<ref name="PMID: 8254661" />

Omp85 has been found in many studies to help integrate beta barrels into the outer membrane in order to allow the autotransporter to complete its duty. Due to the <scene name='Translocator_Domain_of_the_Autotransporter_NalP_within_Neisseria_meningitidis/Hydophilic/1'>hydrophilic nature</scene> of the beta barrel’s hairpin loops on the extracellular side of NaIP, it is impossible for it to breach the cell membrane that is highly hydrophobic. Research on how this occurs in Neisseria meningitides is ongoing and has not been discovered yet. Yet there are many implications that a protein named Omp85 is most likely the helper protein that facilitates this. The large hydrophilic loops on the autotransporter domain might act as a recognition signal for the Omp85 complex to encompass the end of the beta barrel. From here the Omp85 complex which sits on the periplasmic side of the cell membrane is activated and creates a pore and places the beta barrel within the membrane, while preventing the hydrophilic loops from directly coming in contact with the hydrophobic cell membrane. Then the Omp85 molecule is able to integrate the beta barrel into the pore that it created, situating it permanently there. The lag time between Omp85 and the translocator exporting a protein is very small and it is hard to tell whether they can occur simultaneously or only occur simultaneously. <ref name="PMID: 8254661" />