UCL Division of Biosciences


Molecular Machines

Diseases such as cancer, Alzheimer’s, Parkinson’s and type II Diabetes may be caused by defects in the molecular machines that populate the cells in our bodies. The key to preventing and curing such diseases is to understand how these complex machines work. Once scientists identify their structures and processes, then synthetic molecular machines could be developed as therapies to treat these diseases. For example, nano machines could be used to identify and destroy cancer cells. Whereas biology has perfected its machines over billions of years of evolution, scientists are just getting started in imitating them. Perhaps those still at school studying science will be the next generation to make major discoveries in the field of molecular machines?

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Molecular Machines in Detail   

 by Dr Suzanne Ruddy,  Principle Teaching Fellow UCL

About Suzanne Ruddy

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My first career aspirations were to be a professional tennis player or a tourist, but there weren’t many opportunities for tennis and Easyjet had still to colonise the skies when I was growing up.  Fortunately, as a teenager, I experienced the satisfaction of scientific exploration and realised that science gave me a way to ask interesting questions about life and attempt to answer them.  I studied for both my BSc and PhD at Queen’s University Belfast before moving to England to undertake my research career. Even if I had made it as a tennis player, I would have ended up in the same role that I now occupy - that of teaching the next generation of participants. As a senior teaching fellow, I explain some the molecular mechanisms of life to undergraduates, and hope to inspire in my students the same curiosity and awe that perseveres.  


Tiny machines a million times smaller than a millmetre (nanometres) are busy working inside the cells of your body right now. They enact the transfer of information from the genetic  blueprint (DNA) to a working copy (RNA) to create the workforce of the cell - proteins. Proteins drive the processes of life and make up much of the cellular architecture. This information transfer is known as the central dogma, which states that the information contained in DNA is transferred to RNA by transcription, and this in turn is made into protein by the process of translation.  All of this and more is carried out by tiny molecular machines. We probably have lots more molecular machines to discover, but here are a few facts that we know already: 

The Replisome


1.  The Replisome

The replisome replicates DNA when the cell is dividing to make sure that each daughter cell receives a faithful copy of the parent DNA.

transcription machinary


2.  Transcription Machinary

Transcription machinery reads the secure DNA code and makes multiple working copies of the gene on demand. 



The Ribosome


3.  The Ribosome

The ribosome is a kind of translating machine that reads the genetic code of the RNA  and turns it into the cellular workforce and building blocks of the cell - in other words, the proteins.

The Splicosome


4.  The Spliceosome

 The spliceosome is a machine that chops up and reassembles the RNA in different combinations so that different proteins can be made from one original RNA. This is called alternative splicing and when it goes wrong, can result in disease.  



5.  Dynein

Dynein is the Royal Mail of the cell. It walks along paths (microtubules) carrying packages of proteins delivering these to where they are needed, with destinations encoded by address labels in each protein.

ATP Synthase


6.  ATP Synthase

ATP synthase makes the ATP for the cell so that there is a constantly available energy supply to carry out all of the synthetic, mechanical and enzymatic processes in the cell

Understanding these molecular machines is really important to understanding the cell and working out the roots of many diseases such as cancer, neurodegenerative disease, genetic disease and even infectious disease. Are the machines going awry and making the wrong product, or too much or too little of it?  Why?   Can we adapt and use these machines as nanobots to solve problems and deliver drugs, to treat or cure disease, for example?



The Science of Molecular Machines:  a lecture by Professor Finn Werner

Finn Werner is a professor of molecular biophysics in the Division of Biosciences at UCL.  His research investigates RNA synthesis and his findings has been published in Nature - the leading international journal of science which publishes the most significant discoveries.  The following video explains molecular machines and his research.

my enthusiams is driven by curiosity - I want to know how life works  - Finn Werner

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Further Reading

 Samson C.  (2020) "A Splice of Life"  Chemistry World    Clare Sansom explains the complex world of the spliceosome, a molecular machine in all our cells

Nogales E. and Grigorieff N. (2001) " Molecular Machine:  putting the pieces together".  The Journal of Cell Biology, vol.152

Kay E.R. and Leigh D.A. (2015) " Rise of the Molecular Machines"  Wiley online library open access

Further Videos

Speaking of Chemistry    The Nobel Prize in Chemistry:  Molecular Machines explained

Your Body's Molecular Machines

PDB   What is a Protein?  


Key words in this page

The Central Dogma 

The central dogma suggests that DNA contains the information needed to make all of our proteins, and that RNA is a messenger that carries this information to the ribosomes.The ribosomes serve as factories in the cell where the information is ‘translated’ from a code into the functional product, a protein.