Sandbox Reserved 1101: Difference between revisions
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5IZ2 is the '''NTD domain''' of a protein called [https://en.wikipedia.org/wiki/Spidroin_ spidroin]. This protein is a component of the dragline silk. There are several types of spidroin, and those that form the core of the silk are called '''MaSp1''' (Major ampullate Spidroin-1), which are produced by in the major ampullate gland of spiders. | 5IZ2 is the '''NTD domain''' of a protein called [https://en.wikipedia.org/wiki/Spidroin_ spidroin]. This protein is a component of the dragline silk. There are several types of spidroin, and those that form the core of the silk are called '''MaSp1''' (Major ampullate Spidroin-1), which are produced by in the major ampullate gland of spiders. | ||
The NTD domain of these proteins is very important since it plays a major role in the dimerisation of spidroins. Indeed, thanks to the NTD organization, two spidroins can be combined, leading to the production of fibres with exceptional physical qualities. | The NTD domain of these proteins is very important since it plays a major role in the dimerisation of spidroins. Indeed, thanks to the NTD organization, two spidroins can be combined, leading to the production of fibres with exceptional physical qualities. | ||
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Compared with spidroin of other species of spider, the 2 subunits (A and B) of the dimerized NTD of the spidroin produced by ''N. Clavipes'' are slightly different, due to a different helices arrangement. So they do not completely overlap. This allows the creation of new intermolecular contact networks. | Compared with spidroin of other species of spider, the 2 subunits (A and B) of the dimerized NTD of the spidroin produced by ''N. Clavipes'' are slightly different, due to a different helices arrangement. So they do not completely overlap. This allows the creation of new intermolecular contact networks. | ||
<Structure load='5IZ2' size='350' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' /> | |||
== Dimerization of the spidroin by the NTD domain == | == Dimerization of the spidroin by the NTD domain == | ||
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Next, a mutation of residue Glu84 completely destabilize the dimer formation, that shows the importance of the handshake interaction and also the protonation of Glu84, which must be preceded by protonation of Glu79 and Glu119. Similarly, the protonation of Asp17 and Asp53 plays also a key role in the mechanism of NTD dimerization. These protonations are allowed by the lowering of the pH suffered by the NTD during its progression in the spinning duct. | Next, a mutation of residue Glu84 completely destabilize the dimer formation, that shows the importance of the handshake interaction and also the protonation of Glu84, which must be preceded by protonation of Glu79 and Glu119. Similarly, the protonation of Asp17 and Asp53 plays also a key role in the mechanism of NTD dimerization. These protonations are allowed by the lowering of the pH suffered by the NTD during its progression in the spinning duct. | ||
