Pick-up, transport and release of a molecular cargo using a small-molecule robotic arm

• Published in: Nature chemistry 2016-02, Vol.8 (2), p.138-143
• Main Authors: Kassem, Salma, Lee, Alan T. L., Leigh, David A., Markevicius, Augustinas, Solà, Jordi
• Format: Article
• Language: English
• Subjects: 639/638/541; 639/925/927/339; Analytical Chemistry; Biochemistry; Chemistry; Chemistry/Food Science; Inorganic Chemistry; Organic Chemistry; Physical Chemistry
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.2410

Modern-day factory assembly lines often feature robots that pick up, reposition and connect components in a programmed manner. The idea of manipulating molecular fragments in a similar way has to date only been explored using biological building blocks (specifically DNA). Here, we report on a wholly artificial small-molecule robotic arm capable of selectively transporting a molecular cargo in either direction between two spatially distinct, chemically similar, sites on a molecular platform. The arm picks up/releases a 3-mercaptopropanehydrazide cargo by formation/breakage of a disulfide bond, while dynamic hydrazone chemistry controls the cargo binding to the platform. Transport is controlled by selectively inducing conformational and configurational changes within an embedded hydrazone rotary switch that steers the robotic arm. In a three-stage operation, 79–85% of 3-mercaptopropanehydrazide molecules are transported in either (chosen) direction between the two platform sites, without the cargo at any time fully dissociating from the machine nor exchanging with other molecules in the bulk. Factory assembly lines often feature robots that pick up, reposition and connect components in a programmed manner. Now, it has been shown that a molecular machine is able to pick up a cargo, reposition it, set it down and release it at a site approximately 2 nm away from the starting position.