TonB: Difference between revisions

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~~{{STRUCTURE_1xx3 | PDB~~=~~1xx3 | SCENE~~= TonB~~/Ctdtonb/1 }}~~

TonB is involved in the uptake of iron as a component of the TonB/[[ExbB]]/[[ExbD]] complex of the [[Ton]] system.

==Structure==

'''TonB''' spans the periplasm <ref>PMID: 16741125</ref>, with the C-terminus of TonB spanning from residues ~150 to 239<ref name='Postle'>PMID: 21179522</ref>. For more details on the Ton system see [[Ton]].

==Function==

TonB is involved in the uptake of iron as a component of the TonB/[[ExbB]]/[[ExbD]] complex of the [[Ton]] system. It's activity is determined by the presence of ExbB and ExbD<ref name='Kampfenkel'>PMID: 8449962</ref>. The C-terminus of TonB interacts with outer membrane transporters, known as TonB-dependent outer membrane transporters (TBDTs)<ref name=Wiener'>PMID: 16039843</ref>, allowing the translocation of biochemical molecules between the inner and outer membrane<ref name='Postle'>PMID: 21179522</ref>.

==~~Structure~~==

===Interaction with ExbB/ExbD===

TonB and ExbD bind to ExbB in a protein complex that prevents the degradation of the TonB protein. TonB and ExbD are anchored to the cytoplasmic membrane via their N-terminal hydrophobic sequences, with the rest of the protein complex extending into the periplasmic space, allowing for interaction with outer membrane proteins.<ref name='Kampfenkel'>PMID: 8449962</ref>

TonB takes on the role of an energy transducer, while ExbB and ExbD are involved in the transport of biochemical molecules. In order for sucessful energy transduction to occur, there are processes that must occur<ref name='Held'>PMID: 12193634</ref>:

~~==Function==~~

#TonB must couple to the proton gradient of the cytoplasmic membrane

~~The activity of~~ TonB ~~is determined by~~ the ~~presence~~ of ExbB and ExbD. <ref name='~~Kampfenkel~~'>PMID: ~~8449962~~</ref>

#TonB must convert its association with the outer membrane, for which it has high affinity, to that with the cytoplasmic membrane, which is also thought to be high affinity.

===BtuB-TonB Complex===

TonB complexes with [[BtuB]] in order to aid the transport of nutrients such as cobalamins<ref name='Cadieux'>PMID 11029413</ref> across the outer membrane by incorporating the proton-motive force into the outer membrane.<ref name='Shultis'>PMID: 16741124</ref> TonB attaches to BtuB on the periplasmic side of the 614 amino acid BtuB protein<ref name='Shultis'> PMID: 16741124</ref>.

~~{{STRUCTURE_2gsk | PDB=2gsk | SCENE= BtuB-TonB_Complex/Btubtonbcomplex/1 }}~~

===~~Interaction~~ with TonB ~~Box~~===

As shown in the 3D structure to the right (2GSK), TonB complexes with [[BtuB]] in order to aid the transport of nutrients such as cobalamins<ref name='Cadieux'>PMID 11029413</ref> across the outer membrane by incorporating the proton-motive force into the outer membrane.<ref name='Shultis'>PMID: 16741124</ref> TonB attaches to BtuB on the periplasmic side of the 614 amino acid BtuB protein<ref name='Shultis'> PMID: 16741124</ref>.

</StructureSection>

==3D structures of TonB==

Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}

[[1ihr]], [[1qxx]], [[1u07]] – EcTonB C terminal – ''Escherichia coli''

[[1xx3]], [[5lw8]] - EcTonB C terminal – NMR

[[2grx]] - EcTonB + ferrichrome-iron receptor

[[2ivz]] - EcTonB + colicin-E9 peptide

[[2gsk]] - EcTonB C terminal + vitamin B12 transporter BtuB

[[2k9k]] – TonB2 C terminal – ''Listonella anguillarum''

[[6fip]] - PaTonB C terminal – ''Pseudomonas aeruginosa'' - NMR

[[6i97]] - PaTonB C terminal + TonB-dependent receptor

[[5lw8]], [[6sly]] - TonB C terminal – ''Helicobacter pylori'' - NMR

== References==

[[Category:Topic Page]]

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@@ Line 1: / Line 1: @@
-{{STRUCTURE_1xx3 |  PDB=1xx3  |  SCENE= TonB/Ctdtonb/1 }}
+<StructureSection load='1ihr' size='350' side='right' scene='' caption='E. coli TonB C-terminal dimer complex with Br- ions (dark red) (PDB code [[1ihr]])'>
-TonB is involved in the uptake of iron as a component of the TonB/[[ExbB]]/[[ExbD]] complex of the [[Ton]] system.
+==Structure==
+'''TonB''' spans the periplasm <ref>PMID: 16741125</ref>, with the C-terminus of TonB spanning from residues ~150 to 239<ref name='Postle'>PMID: 21179522</ref>.  For more details on the Ton system see [[Ton]].
+==Function==
+TonB is involved in the uptake of iron as a component of the TonB/[[ExbB]]/[[ExbD]] complex of the [[Ton]] system.  It's activity is determined by the presence of ExbB and ExbD<ref name='Kampfenkel'>PMID: 8449962</ref>.  The C-terminus of TonB interacts with outer membrane transporters, known as TonB-dependent outer membrane transporters (TBDTs)<ref name=Wiener'>PMID: 16039843</ref>, allowing the translocation of biochemical molecules between the inner and outer membrane<ref name='Postle'>PMID: 21179522</ref>.
-==Structure==
+===Interaction with ExbB/ExbD===
 TonB and ExbD bind to ExbB in a protein complex that prevents the degradation of the TonB protein. TonB and ExbD are anchored to the cytoplasmic membrane via their N-terminal hydrophobic sequences, with the rest of the protein complex extending into the periplasmic space, allowing for interaction with outer membrane proteins.<ref name='Kampfenkel'>PMID: 8449962</ref>
+TonB takes on the role of an energy transducer, while ExbB and ExbD are involved in the transport of biochemical molecules.  In order for sucessful energy transduction to occur, there are processes that must occur<ref name='Held'>PMID: 12193634</ref>:
-==Function==
+#TonB must couple to the proton gradient of the cytoplasmic membrane
-The activity of TonB is determined by the presence of ExbB and ExbD. <ref name='Kampfenkel'>PMID: 8449962</ref>
+#TonB must convert its association with the outer membrane, for which it has high affinity, to that with the cytoplasmic membrane, which is also thought to be high affinity.
 ===BtuB-TonB Complex===
-TonB complexes with [[BtuB]] in order to aid the transport of nutrients such as cobalamins<ref name='Cadieux'>PMID 11029413</ref> across the outer membrane by incorporating the proton-motive force into the outer membrane.<ref name='Shultis'>PMID: 16741124</ref>  TonB attaches to BtuB on the periplasmic side of the 614 amino acid BtuB protein<ref name='Shultis'> PMID: 16741124</ref>.
-{{STRUCTURE_2gsk |  PDB=2gsk  |  SCENE= BtuB-TonB_Complex/Btubtonbcomplex/1 }}
-===Interaction with TonB Box===
+<StructureSection load='2gsk' size='350' side='right' scene='BtuB-TonB_Complex/Btubtonbcomplex/1' caption='E. coli TonB C-terminal (green) complex with vitamin B12 transporter BtuB (grey) (PDB code [[2gsk]])'>
+As shown in the 3D structure to the right (2GSK), TonB complexes with [[BtuB]] in order to aid the transport of nutrients such as cobalamins<ref name='Cadieux'>PMID 11029413</ref> across the outer membrane by incorporating the proton-motive force into the outer membrane.<ref name='Shultis'>PMID: 16741124</ref>  TonB attaches to BtuB on the periplasmic side of the 614 amino acid BtuB protein<ref name='Shultis'> PMID: 16741124</ref>.
+</StructureSection>
+==3D structures of TonB==
+Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
+[[1ihr]], [[1qxx]], [[1u07]] – EcTonB C terminal – ''Escherichia coli''<br />
+[[1xx3]], [[5lw8]] - EcTonB C terminal – NMR<br />
+[[2grx]] - EcTonB + ferrichrome-iron receptor<br />
+[[2ivz]] - EcTonB + colicin-E9 peptide<br />
+[[2gsk]] - EcTonB C terminal + vitamin B12 transporter BtuB<br />
+[[2k9k]] – TonB2 C terminal – ''Listonella anguillarum''<br />
+[[6fip]] - PaTonB C terminal – ''Pseudomonas aeruginosa'' - NMR<br />
+[[6i97]] - PaTonB C terminal + TonB-dependent receptor <br />
+[[5lw8]], [[6sly]] - TonB C terminal – ''Helicobacter pylori'' - NMR<br />
 == References==
 <references/>
+[[Category:Topic Page]]