| SUBJECT |
Researchers find that CYSTEINE molecules DIMERIZE readily – but they’re picky about their partner’s chirality. Using SCANNING TUNNELING MICROSCOPY to follow the SURFACE stereochemistry, the group reports that depositing L-cysteine molecules on the (110) crystal face of GOLD produces dimmers that appear as paired spots (distorted figure-eights). The features are aligned with a 20 degree clockwise rotation relative to certain lattice features. D-Cysteine molecules act just like their L counterparts, except that the rotation is counterclockwise, leading to the mirror image. “And when we use a racemic mixt.” “we only see LL dimmers & DD dimmers. We don’t observe any heterochiral pairs on the surface To understand cysteine’s stereoselectivity, the group turned to quantum mechanical calculations. The group concludes that cysteine’s behaviour is driven by optimization of the bonds between gold & S, between gold & the NH2 group, & between pairs of –COOH groups. “It’s a system that lets you see – at the molecular level – the 3 contact points needed for chiral recognition” |
| UPDATE | 03.02 |
| AUTHOR | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
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