Sandbox Reserved 717: Difference between revisions
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==Receptor-Binding Domain == | ==Receptor-Binding Domain == | ||
Gp12 is fixed with its N-terminal domain to the baseplate. So the C-terminal domain has to be involved in LPS-binding. To detect where the receptor-binding domain is, full-length gp12, 33kDa fragments and 45kDa fragments were immobilised in micro-plate wells and were allowed to bind to bacteria[1]. The result was that the 33kDa fragment did never bind to a bacteria. The 45kDa fragment did bind. So the receptor-binding domain is absent in the 33kDa fragment but present in the 45kDa fragment. The residues which are present in the 45kDa fragment and lacking in the 33kDa fragment are the residues 397-517. They are referred to be part of the receptor-binding domain. | Gp12 is fixed with its N-terminal domain to the baseplate. So the C-terminal domain has to be involved in LPS-binding. To detect where the receptor-binding domain is, full-length gp12, 33kDa fragments and 45kDa fragments were immobilised in micro-plate wells and were allowed to bind to bacteria[1]. The result was that the 33kDa fragment did never bind to a bacteria. The 45kDa fragment did bind. So the receptor-binding domain is absent in the 33kDa fragment but present in the 45kDa fragment. The residues which are present in the 45kDa fragment and lacking in the 33kDa fragment are the residues 397-517. They are referred to be part of the receptor-binding domain. | ||
The receptor-binding domain can be sub-divided into head and bonnet. On the border between these two subdomains there is a metal-binding site. | The receptor-binding domain can be sub-divided into head and bonnet. On the border between these two subdomains there is a metal-binding site. This site binds presumably to zinc. Two His amino acids (His445 and His447) from each monomere are octahedrally coordinated around the zinc. | ||
The receptor-binding domain can be compared to a flower bud. This flower bud has got 12 petals which are organised in a 3-fold symmetry. At the bottom there are the resisues 406-432 they form the first petal, just above there are the residues 489-504 which form the second petal. The third petal is formed by the residues 450-470 and at the top there are the residues 470-480 and form the fouth petal. The complete and active receptor-binding domain is built by the trimeric protein. This trimeric proteine structure is stabilised by many inter-domain hydrogen bounds. These hydrogen bounds can have the profiles: main-chain-main-chain, main-chain-side-chain and side-chain-side-chain. | |||
== | |||
==The LPS-Bindind Site== | |||
The exact position of the | |||
==Ligands and their Binding-Sites== | |||
==1.)So4== | |||
==2.)citric acid== | |||
==3.)zinc== | |||
