Lee J, Blaber SI, Dubey VK, Blaber M. A polypeptide "building block" for the β-trefoil fold identified by "top-down symmetric deconstruction".
J Mol Biol 2011;
407:744-63. [PMID:
21315087 DOI:
10.1016/j.jmb.2011.02.002]
[Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 01/31/2011] [Accepted: 02/02/2011] [Indexed: 12/31/2022]
Abstract
Fibroblast growth factor-1, a member of the 3-fold symmetric β-trefoil fold, was subjected to a series of symmetric constraint mutations in a process termed "top-down symmetric deconstruction." The mutations enforced a cumulative exact 3-fold symmetry upon symmetrically equivalent positions within the protein and were combined with a stability screen. This process culminated in a β-trefoil protein with exact 3-fold primary-structure symmetry that exhibited excellent folding and stability properties. Subsequent fragmentation of the repeating primary-structure motif yielded a 42-residue polypeptide capable of spontaneous assembly as a homotrimer, producing a thermostable β-trefoil architecture. The results show that despite pronounced reduction in sequence complexity, pure symmetry in the design of a foldable, thermostable β-trefoil fold is possible. The top-down symmetric deconstruction approach provides a novel alternative means to successfully identify a useful polypeptide "building block" for subsequent "bottom-up" de novo design of target protein architecture.
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