User:Eric Martz/5eon: Difference between revisions
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The <scene name='73/733958/Hexamer_of_5eon/5'>surface of the fiber</scene> is mostly charged <font color="blue">'''Lys+'''</font> and <font color="red">'''Glu-'''</font> sidechains, with an occasional Trp or Gln, interspersed with Ala (spheres). | The <scene name='73/733958/Hexamer_of_5eon/5'>surface of the fiber</scene> is mostly charged <font color="blue">'''Lys+'''</font> and <font color="red">'''Glu-'''</font> sidechains, with an occasional Trp or Gln, interspersed with Ala (spheres). | ||
The charges form <scene name='73/733958/Hexamer_of_5eon/2'>helices of opposite charge</scene> on the surface, reminiscent of [[User:Ke Xiao/Geobacter pilus models|Xiao's theoretical model of the ''Geobacter sulfurreducens'' pilus]]. Unlike Xiao's model, none of these form salt bridges (a few opposite charges are water-bridged). [[Cation-pi interactions]] involving Phe cannot form since Phe is buried and Lys is on the surface. A few cation-pi interactions may form between Trp on the surface and Lys. | The charges form <scene name='73/733958/Hexamer_of_5eon/2'>helices of opposite charge</scene> on the surface, reminiscent of [[User:Ke Xiao/Geobacter pilus models|Xiao's theoretical model of the ''Geobacter sulfurreducens'' pilus]]. Terminal charges on the chains were blocked (see below). Unlike Xiao's model, none of these form salt bridges (a few opposite charges are water-bridged). | ||
[[Cation-pi interactions]] involving Phe cannot form since Phe is buried and Lys is on the surface. A few cation-pi interactions may form between Trp on the surface and Lys. | |||
==Sequence== | ==Sequence== | ||
Revision as of 19:09, 17 June 2016
The biological unit of 5eon () is a crystallographic structure of 6 alpha helices assembled into a fiber with a hydrophobic core[1]. The individual peptides are synthetic and were designed to assemble in this manner, with a hydrophobic core rich in phenylalanine. The crystal structure has a resolution of 1.7 Å (very good), and an Rfree of 0.22, which is average for this resolution, indicating that the model is reliable. The . The Phe rings (dark gray) are surrounded by (light gray). The is mostly charged Lys+ and Glu- sidechains, with an occasional Trp or Gln, interspersed with Ala (spheres). The charges form on the surface, reminiscent of Xiao's theoretical model of the Geobacter sulfurreducens pilus. Terminal charges on the chains were blocked (see below). Unlike Xiao's model, none of these form salt bridges (a few opposite charges are water-bridged). Cation-pi interactions involving Phe cannot form since Phe is buried and Lys is on the surface. A few cation-pi interactions may form between Trp on the surface and Lys. SequenceThe peptide sequence is constructed from 4 copies of heptad E L/F K A I A Q/K/W The amino-terminal Glu is acetylated, removing its positive charge. The C-terminal Lys is amidated, removing its negative charge. Here is the sequence of one complete peptide (29 amino acids) showing the heptad repeats. ELKAIAQ EFKAIAK EFKAIAW EFKAIAQ K
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View in FirstGlanceView in FirstGlance
- Asymmetric unit (trimer) of 5eon in FirstGlance
- The biological unit is available from within FirstGlance (Resources tab), but for convenience: Biological unit (hexamer) of 5eon in FirstGlance
References and NotesReferences and Notes
- ↑ Spencer RK, Hochbaum AI. X-ray Crystallographic Structure and Solution Behavior of an Antiparallel Coiled-Coil Hexamer Formed by de Novo Peptides. Biochemistry. 2016 May 27. PMID:27192036 doi:http://dx.doi.org/10.1021/acs.biochem.6b00201