Y.Mou
et al.
(2015).
Computational design and experimental verification of a symmetric protein homodimer.
Proc Natl Acad Sci U S A,
112,
10714-10719.
PubMed id: 26269568
DOI: 10.1073/pnas.1505072112
Computational design and experimental verification of a symmetric protein homodimer.
Y.Mou,
P.S.Huang,
F.C.Hsu,
S.J.Huang,
S.L.Mayo.
ABSTRACT
Homodimers are the most common type of protein assembly in nature and have
distinct features compared with heterodimers and higher order oligomers.
Understanding homodimer interactions at the atomic level is critical both for
elucidating their biological mechanisms of action and for accurate modeling of
complexes of unknown structure. Computation-based design of novel
protein-protein interfaces can serve as a bottom-up method to further our
understanding of protein interactions. Previous studies have demonstrated that
the de novo design of homodimers can be achieved to atomic-level accuracy by
β-strand assembly or through metal-mediated interactions. Here, we report the
design and experimental characterization of a α-helix-mediated homodimer with
C2 symmetry based on a monomeric Drosophila engrailed homeodomain scaffold. A
solution NMR structure shows that the homodimer exhibits parallel helical
packing similar to the design model. Because the mutations leading to dimer
formation resulted in poor thermostability of the system, design success was
facilitated by the introduction of independent thermostabilizing mutations into
the scaffold. This two-step design approach, function and stabilization, is
likely to be generally applicable, especially if the desired scaffold is of low
thermostability.
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