5APX image
Entry Detail
PDB ID:
5APX
Title:
Sequence MATKDDIAN inserted between GCN4 adaptors - Structure T9(6)
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2015-09-17
Release Date:
2016-01-27
Method Details:
Experimental Method:
Resolution:
1.80 Å
R-Value Free:
0.22
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:GENERAL CONTROL PROTEIN GCN4
Mutations:YES
Chain IDs:A, B, C
Chain Length:95
Number of Molecules:3
Biological Source:SACCHAROMYCES CEREVISIAE
Ligand Molecules
Primary Citation

Abstact

Coiled coils are the best-understood protein fold, as their backbone structure can uniquely be described by parametric equations. This level of understanding has allowed their manipulation in unprecedented detail. They do not seem a likely source of surprises, yet we describe here the unexpected formation of a new type of fiber by the simple insertion of two or six residues into the underlying heptad repeat of a parallel, trimeric coiled coil. These insertions strain the supercoil to the breaking point, causing the local formation of short β-strands, which move the path of the chain by 120° around the trimer axis. The result is an α/β coiled coil, which retains only one backbone hydrogen bond per repeat unit from the parent coiled coil. Our results show that a substantially novel backbone structure is possible within the allowed regions of the Ramachandran space with only minor mutations to a known fold.

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Primary Citation of related structures