Dear Tim,
the rings I mean are similar to the one in 4FC4 but to my understanding
FocA does not form helices under physiological conditions.
I am sorry if I was not specific enough. I will give you more details. I
am working on two proteins which are dimers in solution.
The first of them crystallizes as flat rings consisting of four or five
dimers (the rings showing D4 and D5 point group symmetry, respectively),
depending on the crystal form. We got three different crystal forms, one
of which contains the D4 ring, two of which contain the D5 ring.
The second protein is homologous to the first and crstallizes in space
group P1. Through the translational symmetry, the dimers form
pseudo-infinite fibers. The crystal contacts are realized by residues
homologous to the residues that form the interfaces in the rings of the
first protein. These residues are conserved and hence seem to be of
importance.
We now think that these proteins form helices under particular
physiological conditions. We have (weak) biochemical data which support
this assumption and it also makes sense mechanistically. We interpreted
the crystal structures accordingly. We think that these helices are of the
same width as the D4 or D5 rings but with a helical symmetry along the
four- or fivefold axis instead of the purely rotational symmetry. We deem
the rings of the first protein and the fiber of the second protein special
cases of the helix: the rings are helices with a pitch of zero and the
fiber would be a helix with zero turns (or a flat curvature).
A reviewer now does not really follow our argumentation and asked us to
provide him with examples of proteins showing a similar behavior, i.e.
normally forming helices but forming rings (or fibers) in the crystal.
Thanks to everyone for their help.
Best regards,
Joern
******************************************
Address:
Joern Krausze
Molecular Structural Biology
Helmholtz Centre for Infection Research
Inhoffenstrasse 7
38124 Braunschweig
Germany
Email: [email protected]
Phone: +49 (0)531 6181 7023 (office)
+49 (0)531 6181 7020 (lab)
******************************************
On Wed, 5 Jun 2013, Tim Gruene wrote:
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Dear Joern,
I am not sure this is what you have in mind: just yesterday I heard a
talk from Oliver Einsle about FocA ion channels - look at PDB ID 4FC4,
for example forming a (flat) pentamer, and let us know if this is what
you mean.
Best,
Tim
On 06/04/2013 05:24 PM, Joern Krausze wrote:
Dear all,
can anyone provide me with examples for proteins that form a
helical oligomer under physiological conditions and flat rings
(basically a helix with a pitch of 0) in the crystal? I only know
examples of the other way around.
Thank you in advance.
Joern
****************************************** Address:
Joern Krausze Molecular Structural Biology Helmholtz Centre for
Infection Research Inhoffenstrasse 7 38124 Braunschweig Germany
Email: [email protected] Phone: +49 (0)531 6181 7023
(office) +49 (0)531 6181 7020 (lab)
******************************************
________________________________
Helmholtz-Zentrum für Infektionsforschung GmbH | Inhoffenstraße 7
| 38124 Braunschweig | www.helmholtz-hzi.de Das HZI ist seit 2007
zertifiziertes Mitglied im "audit berufundfamilie"
Vorsitzende des Aufsichtsrates: MinDir’in Bärbel Brumme-Bothe,
Bundesministerium für Bildung und Forschung Stellvertreter: Rüdiger
Eichel, Abteilungsleiter Niedersächsisches Ministerium für
Wissenschaft und Kultur Geschäftsführung: Prof. Dr. Dirk Heinz; Ulf
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- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
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________________________________
Helmholtz-Zentrum für Infektionsforschung GmbH | Inhoffenstraße 7 | 38124
Braunschweig | www.helmholtz-hzi.de
Das HZI ist seit 2007 zertifiziertes Mitglied im "audit berufundfamilie"
Vorsitzende des Aufsichtsrates: MinDir’in Bärbel Brumme-Bothe,
Bundesministerium für Bildung und Forschung
Stellvertreter: Rüdiger Eichel, Abteilungsleiter Niedersächsisches Ministerium
für Wissenschaft und Kultur
Geschäftsführung: Prof. Dr. Dirk Heinz; Ulf Richter, MBA
Gesellschaft mit beschränkter Haftung (GmbH)
Sitz der Gesellschaft: Braunschweig
Handelsregister: Amtsgericht Braunschweig, HRB 477
