Exploring the second code of life: protein

Chicken, duck, fish, grains and grains In the eyes of food, it is only food to satisfy the appetite of the stomach and mouth Few people think of the relationship between protein in food and life activities In the view of researchers, protein is the executor of gene function, and the interaction between proteins is the basis of life activities It is not too much to say that protein is the origin of life Like gene science, protein is also an important object of biological research, and protein has a more complex structure than DNA molecule, which has become the second code of life outside gene This subject, which started from egg white research, has now gone deep into reducing cooked eggs to raw eggs, and finding some serious causes of cancer, Alzheimer's disease and so on Recently, the research team led by Shi Yigong, academician of the Chinese Academy of Sciences, published research results in science, which pushed the resolution of a key compound in the assembly process of splicing body of Saccharomyces cerevisiae to near atomic level Another foreign research team announced that it has obtained the world's first single molecule high-precision protein image Related basic research will be helpful for the academic community to further explore the mystery of protein With the progress of molecular medicine, protein medicine is in the golden stage of development In the past five years, commercial protein drugs have been growing at a compound annual growth rate of about 10% At present, the annual market size has exceeded 100 billion US dollars Experts of recombinant protein medicine believe that the market will continue to develop and reach its peak around 2020 The indispensable life energy for the exploration of the key substances supporting life activities, human beings always have some afterknowledge It's just like it took hundreds of millions of years for a living body to breathe air before lavacy determined the composition of the air The earliest record of protein research is less than 300 years ago In the 18th century, proteins were found to be a unique class of biomolecules, which could be coagulated or flocculated by acid treatment Scientists at that time could only confirm that egg white, blood, wheat and so on all contained such molecules In the 19th century, the Dutch chemist Gretel Mulder found that almost all proteins had the same experimental formula by elemental analysis In 1838, his partner, Yongs bezelius, chose to use the term "protein" to describe such molecules Eggs, meat are classified as high protein food, and so on, the human body must also contain a lot of protein Scientific data show that protein accounts for about 18% of the total body mass From hair to brain tissue, from endocrine hormones to bone, are made up of proteins Cells in the human body are regenerating and dying all the time Protein is the most important material for repairing and renewing human tissues The most obvious example is that people who suffer from hunger for a long time and lack of protein intake are always yellow and skinny, with sparse hair And organisms that always get high-quality protein look fuller, both in skin and body In the deep part of the body, different proteins participate in various complex operations like precise machines, such as hemoglobin is responsible for delivering oxygen, lipoprotein is responsible for delivering fat, protease in the digestive tract promotes the digestion, absorption and utilization of food, and more egg white is involved in the acid-base balance of body fluids, the operation of the nervous system, hormone regulation, etc If the double helix structure of DNA in cell carries the genetic code of organism, protein is the energy that drives the life activity In the field of molecular biology, the significance of protein exploration is no less than that of gene research The chemical composition of protein is not complicated It must contain four elements: carbon, hydrogen, oxygen and nitrogen Generally, it also contains more than ten elements such as phosphorus, sulfur and iron However, the structure of protein is more complex than DNA At first, the protein is composed of α - amino acids in a certain order to form a polypeptide chain, which is one-dimensional However, a peptide chain does not have complex functions It must be combined by one or more peptide chains according to its specific way, and a compound with a certain spatial structure can be called a protein This process, like winding, is called protein folding At present, researchers know little about how proteins self assemble and form first-order to fourth-order structures In the past few decades, scientists who have made breakthroughs in the study of protein structure have often won Nobel Prize In the 1960s, Anfinsen, an American scientist, found that unfolded proteins could spontaneously refold in vitro, and proposed a "thermodynamic hypothesis" of protein folding Anfinsen won the 1972 Nobel Prize for chemistry In 1982, Aaron Kruger, a British molecular biologist, won the Nobel Prize in Chemistry for his achievements in developing crystallographic electron diffraction method to determine the three-dimensional structure of nucleic acid protein complexes Three years later, another American scientist won the Nobel Prize for discovering a method for X-ray determination of crystal structure and protein structure Although the difficulty of determining the structure of a protein has been reduced, the variability and diversity of proteins make it necessary for scientists to spend a lot of energy to analyze proteins in organisms But this kind of research is only a small step in the process of revealing the secret of protein Some of the recent revelations are still encouraging At arXiv, a web-based database of scientific papers, a team announced the use of low-energy holographic electron microscopes and graphene materials to capture images of individual proteins It is believed that with this technology, proteins that could not be crystallized before can be resolved in the future, and protein structure can be studied more accurately from various aspects The research team led by Shi Yigong, academician of the Chinese Academy of Sciences, pushed the resolution of a key compound in the assembly process of S.cerevisiae spliceosomes up to 3.8 angstroms, close to the atomic resolution Spliceosome is a kind of complex composed of RNA (nucleic acid) and protein It is also the key to translate RNA into protein and participate in life activities It is one of the most basic molecular machines in eukaryotes However, missplicing of genes or misregulation of spliceosomes are related to many diseases Changing proteins or changing fate is a milestone for scientists in their careers Ordinary people may be more willing to understand the benefits of protein engineering development for human health When the egg is heated, the protein and yolk will coagulate, and the egg cell will become food This change is irreversible in the inherent cognition, which is called the denaturation of protein But a piece of news in 2015 overturned people's ideas According to UCI news, professors at the University of California and Australian scientists in the United States restored frozen chicken protein to its original liquid state According to reports, due to heat and chemical reactions, a transparent protein called lysozyme in eggs will turn white and coagulate, and then generate a new structure Scientists used urea and mechanical equipment to restore frozen proteins to a liquid Professor Gregory Weiss, who conducted the study, said there was a huge potential for technology to separate proteins One hope is to simplify the formation of artificial proteins and significantly reduce the cost of cancer drugs Researchers from the United States say a protein called SIRT1 has been found to extend the lifespan of mice Based on this research, it is possible to develop molecules to reduce age-related metabolic diseases and chronic diseases in the future At present, the research is still in the early stage and will be applied to human someday More studies have shown that some proteins are associated with fatal diseases If we can understand the relationship between protein folding and misfolding, it will provide important clues for the pathogenesis and treatment Recently, the British Cancer Research Institute reported that it has mapped out the "social network" of carcinogenic proteins by analyzing their unique behaviors different from those of non carcinogenic proteins The researchers found that carcinogenic proteins often have special "social behavior" characteristics compared with non carcinogenic proteins Using the computational model to map the interaction of carcinogenic proteins will help researchers better predict the target proteins of anticancer drugs Like erasers, people with Alzheimer's who are gradually erased from their memories have amyloid plaques in their brains The existing medicine is helpless for this disease, and can only watch the patients' intelligence level become lower and lower until they die The research thinks that this disease is related to protein aggregation or misfolding In July 2014, Shi Yigong's team publicly demonstrated the fine three-dimensional structure of the human gamma secretase complex directly related to the onset of Alzheimer's disease Shi yigongbi said that this achievement is equivalent to making people look at a steamed bread from 100 meters to 5 meters The future goal is to reduce the distance to 10 centimeters People with autism may be more unfortunate than people with Alzheimer's Because abnormal chromosomes and candidate genes lead to abnormal protein expression, some people are born lonely and may be lonely forever Qiu Zilong's research group, Institute of neuroscience, Shanghai Academy of Biological Sciences, Chinese Academy of Sciences, discovered the new function of autism related protein MeCP2 MeCP2 is a methylated DNA binding protein that recruits transcriptional inhibition complexes and shuts down gene expression The mutation of MECP2 gene or the increase of its copy number will lead to autism and other developmental nervous system diseases The research team's experiments revealed that MeCP2 is involved in the new function of microRNA shearing, and suggested that this function is related to the pathogenesis of developmental nervous system diseases caused by MECP2 gene mutation Scientists also found that mad cow disease, bird flu and other diseases that made the world talk a few years ago were also related to proteins American biochemist Stanley prusina found a pathogenic factor named prion, which is the main cause of mad cow disease in animals Prion is the old name of protein, that is to say, Stanley thinks that the pathogenic factor is a kind of toxic protein, which is a kind of self replicating and infectious factor composed of protein without nucleic acid Its biological position has not been determined yet After Stanley won the Nobel Prize in physiology and medicine for his discovery, a British research team found that the presence of a protein called glycon-1 would lead to an increase in the number of abnormal prions, further revealing the cause of BSE In January, British scientists published a paper in nature A single protein, anp32a, has been found to limit the operation of avian influenza A virus in mammals Experts commented that the discovery could open the way for the development of new antiviral drugs The gene with great prospect in proteomics is the genetic code of biology Scientists can directly modify the gene to treat some patients, and through gene screening to remind people of the risk of certain diseases However, protein is the executor of gene function, which needs chemical agents to combine with protein directly From here