The regions of instability, especially those that are not embedded in actin binding sites, may allow the supercoil to assume the conformation required for binding to the actin helix, and be responsible for the variable length of the supercoil.
Additional interactions of the protein with headgroups of annular lipids, that is, lipid-binding sites, may allow membrane proteins to select for specific lipids and/or to form tight interactions with lipids important for their function or structural integrity.
Receptors such as HSPG and the 32 k laminin receptor that are abundant at this site may allow binding of AAV serotypes 2, 8, and 9, whereas AAV serotypes such as 1 and 5 that bind sialic acid, which is not found at the ILM, show no expression in the rat retina following intravitreal administration [15], [25], [40].
These enzymes may employ two means to promote protonation of the alkoxide intermediate: a potential proton donor or hydrogen-bonding group within the active site (His271 in PLR; Ser263 and Ser267 in PCBER), and a more open binding site that may allow access to the intermediate by bulk water.
As a result, blocking one binding site may also affect the function of the other binding site.
A lost binding site may have been replaced with a new, species-specific binding site - i.e. binding site turnover.
One possibility is that this domain contains an integrin binding site, and different numbers of integrin binding sites may change the affinity of the intact molecule for a receptor, or may allow for tenascin-W to crosslink numerous receptors.
Mutations in the site in β-propeller or in the unique region had only modest effects on Coro1C-binding affinity, but allowed Coro1B to compete for binding to actin, suggesting that the location of the these binding sites may be in close proximity on the actin filament.
The increase in binding affinity at lower pH was greater for the Ubx optimal binding site than for other DNA binding sites, indicating that subtle sequence alterations in DNA binding sites may influence pH-dependent behavior.
The lower affinity binding sites may represent a novel TxR or an alternative affinity state for the previously characterized high-affinity binding site.
