His-104 is located at the beginning of Loop 5/6, the loop connecting strands β5 and the dimer interface strand, β6+7.
The amino acid residues comprising the interface between strands of the coiled-coil motif are usually hydrophobic and make a major contribution to coiled-coil folding and stability.
We have found that for 15 pairs Galinter provides better superposition of the interface β-strands, and for five pairs I2I-SiteEngines leads to better superposition of these strands.
Roughly 38 000 interface β-strands feature zero or one hot spot residues and are classified as weakly interacting β- strands.
Our studies show that a single Pro substitution at the middle of the dimer interface β-strand is sufficient to generate a fully functional monomer.
In interleukin-8, we substituted Pro for each of the three residues that form H-bonds across the dimer interface β-strands.
We propose that Pro substitution of interface β-strand residues is a viable strategy for generating functional monomers of dimeric, and potentially tetrameric and higher-order oligomeric proteins.
In this study, we show that disrupting backbone H-bonding interactions by substituting dimer interface β-strand residues with proline (Pro) results in fully folded and functional monomers, by exploiting proline's unique feature, the lack of a backbone amide proton.
On the other hand, R41, R43 and D40, which are close to the positively charged patch of R64 and R65 at the electrostatic interface (inter-strand), inhibited MAVS signaling.
Structures of human Cdc42 in complex with the PBDs of Wiskott-Aldrich syndrome protein (WASP) (PDB entry 1CEE 37)) or activated Cdc42 kinase (ACK) (PDB entry 1CF4 39)) exhibit a similar interface along strand β2 of Cdc42, as well as contacts at both switch regions.
