It can be argued that L5 and L23, which also have MDM2 binding properties, may be responsible for the observed increased p53 activity in L11-deficient embryos.
A comparison of the structure-induction (involving rat and mouse Ah receptor binding) and structure-toxicity (in vivo guinea pig toxicity) relationships suggests that two receptors with structurally distinct binding properties may be involved.
As in the case of the Duffy antigen binding chemokines, this erythrocytic property may be important in absorbing excess stimulant signals intended for inflammatory cells, thereby modulating immune responses [ 21].
Although few G225R mutations were found, they were all found in avian hosts, indicating that the mutation can occur sporadically and avian-like receptor-binding properties may not be fully abolished by G225R.
The telomere-binding properties may also be a subject of rapid adaptive coevolution of function as occurs with another essential structure, centromeric repeats and specific centromeric histone types (Malik and Henikoff 2001).
New catalytic activities and metal binding properties may have evolved, as is the case of the tyrosinase-related protein 2, which uses zinc instead of copper as cofactor.
In vivo, it is possible that "good" binding properties promotes proliferation and/or survival, but that also NK cells with less good self-MHC binding properties may pass selection and survive, although to a lesser extent.
Alternatively, high-affinity binding may be a property of all Pellino FHA domains, but we have not identified the optimal binding motif for Pellino1, -3a, or -3b in this study.
The differences in their binding abilities may be explained by the intrinsic properties of their respective CBM.
