{"id":689,"date":"2017-01-13T11:30:26","date_gmt":"2017-01-13T11:30:26","guid":{"rendered":"http:\/\/www.mub.eps.manchester.ac.uk\/in-abstract\/?p=689"},"modified":"2017-07-25T09:53:16","modified_gmt":"2017-07-25T08:53:16","slug":"braiding-a-molecular-knot-with-eight-crossings","status":"publish","type":"post","link":"https:\/\/www.mub.eps.manchester.ac.uk\/in-abstract\/braiding-a-molecular-knot-with-eight-crossings\/","title":{"rendered":"Braiding a molecular knot with eight crossings"},"content":{"rendered":"

Tying the tightest knot<\/h4>\n

As every fisherman and sailor knows, different types of knots have different characteristics that make them more or less suited for a particular task: \u2018bend knots\u2019 give the strongest binding between two lengths of rope; \u2018hitches\u2019 are best for tying rope around an object; and \u2018loop knots\u2019, or \u2018nooses\u2019, allow degrees of movement between the components they connect. There is no reason to believe that different types of knots won\u2019t be just as important, versatile and useful in the molecular world. But we can\u2019t find out about that until we can make them.<\/p>\n

Knots occur in DNA and approximately 1% of proteins, and they form spontaneously in polymer chains (just as happens with plates of spaghetti and headphone cables!). However, until now synthetic chemists have only been able to make the simplest types of molecular knot, such as trefoil (three crossing) and pentafoil (five crossing) knots. This is partly because the most widely used methods to make molecular knots twist two ligand strands around one another. The unavailability of all but the simplest molecular knots hinders the investigation of the effects of different knot types in materials and other molecular applications.<\/p>\n

Now scientists at the University of Manchester have developed a way of braiding three molecular strands enabling tighter and more complex knots to be made than has previously been possible. The Manchester scientists made a molecular knot with eight crossings in a loop just 192 atoms long. The synthesis of the eight-crossing molecular knot illustrates a strategy (the braiding of three strands) that should be applicable to the synthesis of many more, and more diverse, types of molecular knots. By making different types of molecular knot we can find out about their properties (such as at which point are entangled molecular strands prone to breaking?) and which knots have properties best suited for a particular purpose, just as a fisherman or sailor knows which knot is best suited for each task.<\/p>\n

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