0 a part of a molecule, especially a molecule of protein --
1 a part of a molecule, esp. a molecule of protein (= chemical in all living cells) --
However, since most channels are tetrameric and the voltage sensor in each subunit must activate, more than one transition is normally needed to describe activation.
The only essential feature is that there are two discrete relative dispositions of the subunits.
In neutron scattering the distances between pairs of deuterated subunits in large complexes can be determined in this way.
Despite their functional similarities, these two receptor subtypes can be distinguished pharmacologically and are assembled from different protein subunits.
Occasional immunolabeling was also found associated with heterochromatin, suggesting that some of the subunits may be localized to nuclear regions of less active chromatin.
In this contribution, the possibility of observing these loops, as well as other possible subunits, in crystallized proteins will be investigated.
When all subunits are activated, the channel is open.
All the axial structures are helical assemblies of subunit proteins and are therefore likely to have a central channel.