TolQ: Difference between revisions
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TolQ is a polytopic protein located in the inner membrane. | [[Image:TolQ.jpg|600px|right|thumb| The TolQ Membrane-spanning domains <ref>PMID: 8662905</ref>]] | ||
==Structure== | |||
'''TolQ''' is a polytopic protein located in the inner (cytoplasmic) membrane, containing approximately 230 amino acids. There are three membrane spanning segments in TolQ with each segment containing an α-helix<ref>PMID: 7853390</ref>. TM1 is connected to TM2 via a large cytoplasmic loop, with the N-terminal ending in the periplasm. This topology is also found in [[ExbB]], which can be explained by the similar sequence shared by both proteins<ref name='Braun'>PMID: 15205446</ref>. | |||
It has been shown that 4 to 6 TolQ molecules associate in the TolQRA complex, and that they form multimers which interact with the transmembrane helices (TMH) of TolQ, [[TolR]] and [[TolA]]<ref> PMID: 21285349</ref>. The multimers are formed by the three TMHs of TolQ, the last of which undergo a conformational change to form a hairpin, while the first TMH forms an intermolecular interaction<ref name='Vianney'> PMID:8300535</ref>. | |||
== | ==Function== | ||
TolQ plays an important role in the maintenance of the bacterial envelope integrity as well as the import of filamentous bacteriophage and group A colicins<ref name='Vianney'> PMID:8300535</ref>. | |||
Loss of TolQ function can be partially replaced by ExbB and vice versa - reduced activities of either of these proteins via a mutant form can be reversed by introducing double mutants<ref name='Braun'>PMID: 15205446</ref>. | |||
== References== | |||
<references/> | |||
