4U3H: Crystal Structure Of Fn3con

Citation:
Abstract
Consensus protein design is a rapid and reliable technique for the improvement of protein stability, which relies on the use of homologous protein sequences. To enhance the stability of a fibronectin type III (FN3) domain, consensus design was employed using an alignment of 2123 sequences. The resulting FN3 domain, FN3con, has unprecedented stability, with a melting temperature >100 degrees C, a DeltaGD-N of 15.5 kcal mol(-1) and a greatly reduced unfolding rate compared with wild-type. To determine the underlying molecular basis for stability, an X-ray crystal structure of FN3con was determined to 2.0 A and compared with other FN3 domains of varying stabilities. The structure of FN3con reveals significantly increased salt bridge interactions that are cooperatively networked, and a highly optimized hydrophobic core. Molecular dynamics simulations of FN3con and comparison structures show the cooperative power of electrostatic and hydrophobic networks in improving FN3con stability. Taken together, our data reveal that FN3con stability does not result from a single mechanism, but rather the combination of several features and the removal of non-conserved, unfavorable interactions. The large number of sequences employed in this study has most likely enhanced the robustness of the consensus design, which is now possible due to the increased sequence availability in the post-genomic era. These studies increase our knowledge of the molecular mechanisms that govern stability and demonstrate the rising potential for enhancing stability via the consensus method.
PDB ID: 4U3HDownload
MMDB ID: 126900
PDB Deposition Date: 2014/7/21
Updated in MMDB: 2015/03
Experimental Method:
x-ray diffraction
Resolution: 1.98  Å
Source Organism:
Similar Structures:
Biological Unit for 4U3H: monomeric; determined by author and by software (PISA)
Molecular Components in 4U3H
Label Count Molecule
Protein (1 molecule)
1
Fn3con
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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