User:Nikhil Malvankar/Geobacter pilus structure and function: Difference between revisions

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-<span style="font-size:180%"><b>Structure of novel pili evolved for extracellular translocation of microbial nanowires.</b></span>
+<span style="font-size:160%"><b>Structure of ''Geobacter'' pili reveals secretory rather than nanowire behavior.</b></span>
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 [[User:Yangqi Gu|Yangqi '''Gu''']],
 [[User:Vishok Srikanth|Vishok '''Srikanth''']],
+Aldo I. '''[https://www.linkedin.com/in/aldo-salazar-morales-7a866617 Salazar-Morales]''',
 Ruchi '''Jain''',
-Aldo I. '''[https://www.linkedin.com/in/aldo-salazar-morales-7a866617 Salazar-Morales]''',
 J. Patrick '''[https://malvankarlab.yale.edu/group-members O'Brien]''',
 Sophia M. '''[https://malvankarlab.yale.edu/group-members Yi]''',
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 Fadel A. [[User:Fadel A. Samatey|'''Samatey''']],
 Sibel Ebru '''[https://medicine.yale.edu/profile/sibel_yalcin/ Yalcin]''',
-and Nikhil S. '''[https://malvankarlab.yale.edu/pi Malvankar]'''.
+and Nikhil S. '''[[User:Nikhil_Malvankar|Malvankar]]'''.
-(journal article link here) (2021).
+[https://www.nature.com/articles/s41586-021-03857-w nature.com/articles/s41586-021-03857-w] (2021).
-(DOI link here)
+[https://doi.org/10.1038/s41586-021-03857-w DOI 10.1038/s41586-021-03857-w]
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 ===Pilus Structure===
+{{Template:ClickGreenLinks}}
 Our electron cryomicroscopic structure of ''Geobacter sulfurreducens'' pili (<scene name='83/834714/Filament/7'>restore initial scene</scene>), [[6vk9]], reveals them to be <scene name='83/834714/Filament/9'>composed of a core</scene> of '''<font color='#e87000'>PilA-N</font>''' (61 amino acids) coated with an outer surface layer of '''<font color='00a0a0'>PilA-C</font>''' (104 amino acids). Here is a <scene name='83/834714/Filament/10'>cutaway view</scene> (front half hidden). The C-termini of '''<font color='#e87000'>PilA-N</font>''' <scene name='83/834714/Filament/3'>protrude into sockets</scene> in '''<font color='00a0a0'>PilA-C</font>'''.
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 ===Heterodimers===
-The pilus filament is assembled from <scene name='83/834714/Dimer/5'>heterodimers</scene>. Dimer <scene name='83/834714/Dimer/6'>secondary structure</scene>: '''<font color='#e87000'>PilA-N</font>''' consists of two alpha helices, while '''<font color='00a0a0'>PilA-C</font>''' includes a 3-stranded beta sheet. The C-terminal protrusion of '''<font color='#e87000'>PilA-N</font>''' is <scene name='83/834714/Flaps/4'>held between two flaps</scene> (darker) of '''<font color='00a0a0'>PilA-C</font>'''. The flaps have almost no contact with each other. They are held in place by apolar contacts and hydrogen bonds with the C-terminal protrusion of '''<font color='#e87000'>PilA-N</font>'''. These flaps might be open before '''<font color='#e87000'>PilA-N</font>''' arrives to form a dimer, reminiscent of the flaps of HIV protease<ref>PMID: 16418268</ref>. (See, for example, [[1hxw]] and [[Flaps Morph for HIV Protease]].) <scene name='83/834714/Flaps/6'>Four glycines</scene> (<font color="red">'''red: 10, 11, 31, 37'''</font>) provide flexibility that could enable opening of the flaps.
+The pilus filament is assembled from <scene name='83/834714/Dimer/5'>heterodimers</scene>. Dimer <scene name='83/834714/Dimer/6'>secondary structure</scene>: '''<font color='#e87000'>PilA-N</font>''' consists of two alpha helices, while '''<font color='00a0a0'>PilA-C</font>''' includes a 3-stranded beta sheet. The C-terminal protrusion of '''<font color='#e87000'>PilA-N</font>''' is <scene name='83/834714/Flaps/7'>held between two flaps</scene> (darker) of '''<font color='00a0a0'>PilA-C</font>'''. The flaps have almost no contact with each other. They are held in place by apolar contacts and hydrogen bonds with the C-terminal protrusion of '''<font color='#e87000'>PilA-N</font>'''. These flaps might be open before '''<font color='#e87000'>PilA-N</font>''' arrives to form a dimer, reminiscent of the flaps of HIV protease<ref>PMID: 16418268</ref>. (See, for example, [[1hxw]] and [[Flaps Morph for HIV Protease]].) <scene name='83/834714/Flaps/8'>Four glycines</scene> (<font color="red">'''red: 10, 11, 31, 37'''</font>) provide flexibility that could enable opening of the flaps.
 ===Other Findings and Conclusions===
-As detailed in the journal publication, the PilA-N-C pili studied here are 50-fold less electrically conductive than the nanowires composed of cytochromes<ref name="nw1" /><ref name="nw2" />. These PilA-N-C pili lack the structural hallmarks of type 4 pili, but share structural characteristics with pseudopili.  PilA-N and PilA-C remain in the inner membrane, unless the gene for OmcS (or OmcZ) is deleted, in which case they form the pili extending outside the cell studied here. When the ''pilA-N'' gene is deleted, OmcS nanowires fail to be produced. It is proposed in the journal publication that PilA-N-C is part of a secretion system required for production of OmcS/OmcZ nanowires.
+As detailed in the journal publication, the PilA-N-C pili studied here are 20-fold less electrically conductive than the nanowires composed of OmcS cytochromes<ref name="nw1" /><ref name="nw2" />, and 20,000-fold less conductive than OmcZ nanowires<ref name="omcz" />. These PilA-N-C pili lack the structural hallmarks of type 4 pili, but share structural characteristics with pseudopili.  PilA-N and PilA-C remain in the inner membrane, unless the gene for OmcS (or OmcZ) is deleted, in which case they form the pili extending outside the cell studied here. When the ''pilA-N'' gene is deleted, OmcS nanowires fail to be produced. It is proposed in the journal publication that PilA-N-C is part of a secretion system required for production of OmcS/OmcZ nanowires.
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 ==See Also==
+* [[6vk9]], the structure described here.
 * [[Malvankar]]: A list of all interactive 3D complements for publications from the Malvankar group, including:
 ** Structure of the OmcS conductive nanowire: [[Malvankar/2|2019, Cell: Structure of Microbial Nanowires Reveals Stacked Hemes that Transport Electrons over Micrometers.]]