Scientists decode enzyme causing ageing, cancer
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it can also be linked to disease1 elated scientists announced wednesday the completion of a 20-year quest to map the complex enzyme thought to forestall ageing by repairing the tips of chromosomes in plants and animals including humans1 it has been a long time coming lead investigator kathleen collins a molecular biologist at the university of california in berkley said in a statement1 our findings provide a structural framework for understanding human telomerase disease mutations and represent an important step towards telomerase-related clinical therapeutics1 part protein and part rna genetic material that relays instructions for building proteins telomerase acts on microscopic sheaths known as telomeres that cover the tips of the chromosomes found inside all cells1 in humans each cell contains 23 pairs of chromosomes including one pair of sex chromosomes the x and y that differ between males and females1 australian-american biologist elizabeth blackburn who shared the 2009 nobel prize in medicine for discovering telomeres and their protective function in the 1970s likened them to the tiny plastic caps that keep shoelaces from fraying1 eventually however shoelace tips and telomeres do break down every time a cell divides the telomeres get worn a little bit more until the cell stops dividing and dies. this biologists agree is probably central to the natural ageing process1 but there is a twist1 in 1985 blackburn discovered telomerase and its remarkable capacity to extend a cells lifespan by essentially rebuilding telomeres with extra bits of dna much in the same way that retreading a tyre can make it nearly as good as new1 telomerase in other words was revealed to be a key agent in longevity1 decoding the architecture of the enzyme called telomerase could lead to drugs that slow or block the ageing process along with new treatments for cancer they reported in the journal nature1 inherited genetic mutations that compromise telomerase function cause disorders said michael stone a professor at the centre for molecular biology or rna at the university of california santa cruz1 a deficiency of the enzyme could accelerate cell death. at the other extreme too much telomerase supports unbridled cell growth in most human cancers he wrote in a commentary also in nature1 but early efforts to develop drugs that could control the enzymes expression essentially switching it on or off were hampered by an incomplete understanding of the structure and organisation of the telomerase complex stone added1 a 2010 study showed that ageing could be reversed in mice that were treated with telomerase.and in 2011 scientists found a way to transform age-worn cells from people over 90 into rejuvenated stem cells indistinguishable from those found in embryos. in lab experiments several critical markers of ageing in cells were reset including the size of telomeres1 to crack the telomerase code collins and her team used a state-of-the-art cryoelectron microscope cryo-em to see the enzyme in action at unprecedented resolutions of seven or eight angstroms1 an angstrom is one ten-billionth of a metre long1 cryo-em can decipher the molecular structures of compounds that cannot be crystalized and imaged with x-rays. its developers won the 2017 nobel prize in chemistry1 when i got to the point where i could see all the subunits we had 11 proteins in total it was a moment of wow wow this is how they all fit together said lead author thi hoang duong nguyen a post-doc at uc berkeleys miller institute for basic research in science1 a 2010 study showed that ageing could be reversed in mice that were treated with telomerase1 and in 2011 scientists found a way to transform age-worn cells from people over 90 into rejuvenated stem cells indistinguishable from those found in embryos1 in lab experiments several critical markers of ageing in cells were reset including the size of telomeres1