1SHM: Convergent Solutions To Vhh Domain Stabilization From Natural And In Vitro Evolution

The diversity of natural antibodies is limited by the genetic mechanisms that engender diversity and the functional requirements of antigen binding. Using an in vitro-evolved autonomous heavy chain variable domain (V(H)H-RIG), we have investigated the limits of structurally-tolerated diversity in the three complementarity-determining regions and a fourth loop within the third framework region. We determined the X-ray crystal structure of the V(H)H-RIG domain at 1.9A resolution and used it to guide the design of phage-displayed libraries encompassing the four loops. The libraries were subjected to selections for structural stability, and a database of structurally-tolerated sequences was compiled from the sequences of approximately 1000 unique clones. The results reveal that all four loops accommodate significantly greater diversity than is observed in nature. Thus, it appears that most sequence biases in the natural immune repertoire arise from factors other than structural constraints and, consequently, it should be possible to enhance the functions of antibodies significantly through in vitro evolution.
PDB ID: 1SHMDownload
MMDB ID: 32212
PDB Deposition Date: 2004/2/26
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 1SHM: monomeric; determined by author
Molecular Components in 1SHM
Label Count Molecule
Protein (1 molecule)
Antibody RIG
Molecule annotation
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Citing MMDB