Franz-Ulrich Hartl (left) and Arthur Horidge (right)
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For their contributions to the molecular mechanism of protein folding, the German biochemist Franz-Ulrich Hartl (1957-), director of the Max Planck Institute for Biochemistry, and Arthur L. Horwich (1951-), an American biologist at yale School of Medicine, have won almost all international awards in biochemistry and related disciplines except the Nobel Prize.
In 2011, the same year tu received the Lasker Award for Clinical Medicine, Hartl and Horidge also received the Lasker Prize for Basic Medicine. In 2020, Hartle and Holrich won another Nobel Prize weathervane, the American Life Sciences Breakthrough Award, and are regulars on the Nobel Prize prediction list.
The folding mechanism of proteins is an important biological question. Intellectuals has launched a special column entitled "Nobel Prize Worth" to introduce readers to important scientific discoveries and the stories behind them.
Talent hits a target no one else can hit; genius hits a target no one else can see.
Talent and mortals cannot reach, geniuses and mortals cannot see. —— Schopenhauer
Written by | Zongan Wang (Ph.D., Computational Chemistry, University of Chicago)
Editor-in-charge | Liu Chu
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<h1 class="pgc-h-arrow-right" data-track="155" > two of Hartl's favorites</h1>
Born in 1957 in the West German industrial city of Essen, Franz-Ulrich Hartl moved with his parents to a small town in the northern Black Forest at the age of four. In the woods, catching frogs and catching salamanders, wading through streams to build dams, Hartl spent a wonderful childhood. At the age of five, Hartl began to learn musical notation, followed by the wooden flute, flute and piano, and music became one of his two lifelong hobbies. Another hobby is biology! To be precise, Hartl's interest in biology was to capture and collect insects, make specimens, and observe them with microscopes. "Lured him into the pit" was his grandfather, an amateur microscope master. After entering high school, Hartl found a new hobby: biochemistry. [1]
At the age of 19, Hartle entered the medical school of Heidelberg University. While completing the necessary medical training, Hartl pursues a PhD in the Department of Biochemistry. During this time, he discovered that a class of organelle peroxisomes in hepatocytes can be activated by thyroid hormone metabolism and induce massive proliferation [2].
In 1985, Hartl's doctoral dissertation was sent to Walter Neupert (1939–2019), a prominent cell biologist at the University of Munich.[3] Noppett appreciated the paper and invited Hartl to his lab to do post-doctoral research – a crucial turning point in Hartl's life.
For Hartle, this turn of events has a double meaning. On the one hand, his mentor Noppet sent him to Greece in 1986 for a summer study in molecular biology, which made him acquainted with his future life lover and scientific helper Manajit; on the other hand, in the Noppett experimental group, he studied mitochondrial uptake (import) of new synthetic proteins, giving birth to the work of his molecular chaperone.
Hartl and his wife, Manajit, received the Breakthrough Award in Life Sciences in 2020 | Photo copyright: Miikka Skaffari
<h1 class="pgc-h-arrow-right" Data-track="156" > Anfinson's law for protein folding</h1>
Let's start by talking about how proteins fold within cells.
Christian Boehmer Anfinsen (1916 – 1995), winner of the 1972 Nobel Prize in Chemistry, speculated that the natural structure of small water-soluble proteins under physiological environmental conditions depends only on their amino acid sequences [4]. This is known as Anfinsen's dogma, also known as thermodynamic hypothesis of protein folding.
The Anfinson's law is the cornerstone of the computational prediction of protein structure today, and it is also possible to say that it is a public set, and it is an indisputable law that needs to be recognized in advance- under this public framework.
Anfensen himself made this hypothesis based on research on ribonuclease A. He observed that by denaturing the purified physiologically active enzyme so that its polypeptide long chains were opened ( unfold ) , and then reducing the denaturant concentration by diluting the solution , the already defolded protein spontaneously regained enzyme activity. This suggests that the enzyme is spontaneously and correctly folded back, i.e., the amino acid sequence of the enzyme is sufficient to specifically determine its three-dimensional structure and enzyme function.
More specifically, enzyme folding does not require the assistance of other proteins and does not require the input of additional energy (such as ATP).
Such a concise, clear, and beautiful physical understanding was not easy to accept at the time, and it could even be described as earth-shattering. Another protagonist of this article many years later, Arthur Horidge, recalled [5], "When Anfensen won the Nobel Prize, he and the lab team discussed for many days in a row, which was simply shocking, Anfinson was really bold, how could he expect to let the sex-altered protein fold back and restore function?" ”
Of course, the folding described by Anfenson's law occurs under the so-called in vitro (in vitro) experimental conditions. In intracellular protein folding, i.e. in vivo (in vivo), the situation is much more complicated even if the basic laws remain unchanged.
You can imagine that amino acids are chained together in the ribosin body of the protein manufacturing plant to produce a new protein, which, like a piece of toothpaste squeezed out, leaves the ribosome and enters the cytoplasm. Some of the amino acid residues on the long chain of this unfolded protein are oily and sticky, while others are moist and slippery. Greasy residues tend to polymerize and are embedded inside the protein, and hydrated residues tend to be exposed outward-facing, in contact with an external aqueous solution.
Now the question arises: the cell is very crowded, full of folded, semi-folded, undributed, and even misfolded protein molecules, how can you ensure that your folding is not disturbed by the molecules next to it?
<h1 class="pgc-h-arrow-right" data-track="157" > found fold enzymes</h1>
In the past 30 years since Anfinson proposed the thermodynamic hypothesis of protein folding, in the past 30 years, the cornerstone-like law has influenced the attitude of the entire biological community to the problem of protein folding. Hartl recalls [5], "Cell biologists are just not interested in protein folding, which is the field of biophysicists and biochemists who study the spontaneous reaction of proteins in test tubes." ”
Until the end of the 1980s, the scientific trajectories of the two young men intersected with each other.
The older Horich returned to Yale after finishing his pediatric residency training and joined the group of Leon Emanuel Rosenberg (1933-) dean of the Faculty of Medicine. Holrich, who was still obsessed with protein folding, hoped to pick a pediatric disease, combined with the existing DNA recombinant technology at the time, to elucidate its pathogenesis from a molecular biological point of view. He targeted a rare genetic disease of the X chromosome: ornithine transcarboxylase deficiency (OTC) deficiency. OTC is a mitochondrial enzyme. Newborns who inherit this fatal disease cannot metabolize urea normally, and blood ammonia is elevated.
Horidge's research found that OTC is synthesized within the cytosol, but must enter the mitochondria in order to function. Using yeast as a vector to screen for genetic mutations in human enzymes, he found that a special yeast mutant was able to transport OCT into mitochondria, but OTC did not have enzyme activity. Then there may be two situations: (1) OTC does not actually enter the mitochondria; (2) OTC enters the mitochondria, but it does not fold properly, so it cannot perform catalytic function.
There are two sides to the conversation. On the other side of the Atlantic, Hartl had just begun studying the transport of proteins within cells, specifically how proteins enter the mitochondria. During the course of the study, Hartl realized that proteins must first be opened, enter the mitochondria, and then refolded into a functional state. It's no coincidence that Horich and Hartl's research complements each other!
Schematic diagram of protein entering mitochondria[6]
In 1988, Hartl's mentor, Norpet, made a transoceanic phone call to Horich. Horich almost dropped his phone and went to buy a plane ticket to Munich. [5]
In the face of The result hoolitch, Noppett and the students, despite their excitement, remain skeptical — to prove the existence of a protein that aids OTC folding, it must be shown that OTC is fully inside the mitochondria, because the OTC may "get stuck" during the passage through the mitochondrial membrane, in which case the OTC in an open state may be cut off and inactive. At this time, Hartl took the initiative to ask miao, to do the experiment himself.
In just a few weeks, Hartl made the results of the experiment -- OTC did fully enter the mitochondria. This means that there is indeed a foldase in the mitochondria. Hartl, Horidge, and Norpeter published two landmark papers in Nature in 1989 [7-8]: The era of Anfinson's law dominating protein folding was over.
At the age of 32, Hartle spent a few weeks doing the job that would make him famous in the scientific community.
Literature [7] Demonstrate that a heat shock protein in mitochondria called hsp60 plays a key role in the assembly of proteins that enter the mitochondria. Because hsp60 fits John Ellis' 1987 definition of "molecular chaperone," it is classified as a chaperone protein. [9] The paper's lead author, CHENG Ming Y., top right, was one of Horich's earliest graduate students and has retired from the Department of Life Sciences and Institute of Genomics Sciences, National Yang Ming University, Taiwan Province. Horich described her as a "fearless experimentalist." [10-11]
The literature [8] further demonstrates that protein folding in mitochondria requires hsp60 and consumes the energy of ATP hydrolysis.
<h1 class="pgc-h-arrow-right" data-track="158" > chaperone: heat shock protein</h1>
Hartl and Horidge have won numerous awards together, including the 2011 Lasker Prize for Basic Medical Research. Titia de Lange, a Dutch genetics cell biologist and professor at Rockefeller University, was the introducer of the two who won the Lasker Prize.
Drauhe made a very subtle analogy in introducing the duo's award-winning work to illustrate the function of the heat shock protein HSP60:
"The Hsp60 system is like a prison that can hold proteins in a single cell - it's like the American penal system, but it removes the inhumane part and is more efficient. Hsp60 is shaped like a drum, grabs the sticky part of the defolded protein molecule, drags it into the bucket, and closes the lid. The protein molecules caught in hsp60 at this point attempt various pose conformations to fold without having to collide with other protein molecules. The walls of the Hsp60 are highly charged. The protein molecule is held inside the barrel for about 10 seconds, and it is conceivable that it struggles, twists, and hits the wall in the process until the barrel door opens. The jailbreaker may have completed the correct folding and become a good citizen of the vast proteins in the cell, or he may not have completed the folding. Such repeat offenders are quickly captured and escorted into another cage. This process of capture and indulgence may be repeated ten times before it finally allows a polypeptide chain to fold correctly, and then bail is granted, allowed to get out of prison, and like a model citizen, to perform his duties and never have any indiscriminate contact with other protein molecules. ”
"The work of Hartl and Holrich has greatly deepened our understanding of the function of cell life, which has a wide range of applications in medicine and pharmacy. Almost all proteins require some form of involvement of a chaperone during their maturation, and almost all living organisms use "solitary confinement" to drive a portion of their proteins to fold correctly. Chaperone-assisted protein folding gives us many insights into diseases caused by protein variation, such as Alzheimer's, Parkinson's, Lou Jariger's disease (also known as amyotrophic lateral sclerosis, alzheimer's disease), etc. ” [6]
Function diagram of Hsp60-Hsp10 chaperone complex[12]
<h1 class="pgc-h-arrow-right" data-track="159" > Hartl's academic genealogy</h1>
I have a habit of recounting the deeds of a scientist: it is inevitable to examine his academic genealogy. Hartle is a Scientist trained in Germany, and in the context of the current overall leadership of the American life sciences in Europe and East Asia, it may give us some useful inspiration to trace his mentorship.
Hartle's academic career consisted of three supervisors: Doctoral Supervisor, Chemist, Professor at Heidelberg University School of Medicine Hans Schimassek, Postdoctoral Supervisor, Cell Biologist, Professor Walter Noppett of the University of Munich, and Postdoctoral Supervisor, Biochemist, and Professor at Dartmouth College William T. Wickner.
Hartl has described his experience at Professor Noppett as a major turning point in his life, so let's focus on climbing the tree of Noppet's lineage.
According to the academictree.org, Wikipedia, nobelprize.org and other websites, the author shows the academic intergenerational inheritance relationship to the right from the far left, and the red font near the black arrow indicates the specific relationship between the tutor and the student and the time when the former guided the latter. The main field to which each scientist belongs is written below the year of his birth and death. In particular, I mark the student's main research direction in blue; for example, Noppett's main job at his doctoral supervisor, Theodor Bücher, is to study the formation and morphology of mitochondria. [13]
Several of the seven scientists shown in this chart have particularly loud names.
Otto Heinrich Warburg was awarded the 1931 Nobel Prize in Physiology and Medicine for his discovery and research on respiratory enzymes.
Hermann Emil Fischer won the 1902 Nobel Prize in Chemistry for his synthesis of purines and sugars, but he became more famous for the Fischer projection, which is a must-have for undergraduate organic chemistry classes.
August Kekulé may be more famous, after all, the Kekulé structure of the benzene ring enters high school textbooks, and even his dream (Kekulé's dream), who came up with the painstaking structure of the benzene ring because of his dream of ouroboros, entered the high school textbook.
Adolf von Baeyer, who won the 1905 Nobel Prize in Chemistry for synthesizing indigo, lagged behind his phD student, Fischer, who couldn't be too good; he also discovered phthalide and entered the junior high school textbook.
We can see that Fisher → Waldberg→ Buschaugh → Norpeth → Hartl, their research is in the same vein, gradually advancing, very coherent. During his Ph.D., Walberg meticulously studied the role and metabolic mechanism of peptide molecules in respiration-related oxidation reactions, and because of his medical background, Büshaw devoted himself to understanding the redox reaction of hemoglobin during his Ph.D.; then, when Noppett began his Ph.D., studying how the mitochondria of cellular respiration formed and functioned, it became the focus of cell biology at that time; and then Hartl happened to discover molecular chaperones from the study of mitochondrial transport proteins. Logical.
bibliography:
[1] Autobiography of Franz-Ulrich Hartl (2012)
[2] The control of peroxisomal enzyme activities by thyroid hormone in the rat's liver. DNB 850819857, Dissertation, Heidelberg 1985.
[3] Obituray: Water Neupert (1939 – 2019), Cell 178, August 22, 2019
[4] Principles that Govern the Folding of Protein Chains, Science 181 (1973) 223-230
[5] A mystery unfolds: Franz-Ulrich Hartl and Arthur L. Horwich win the 2011 Albert Lasker Basic Medical Research Award
[6] laskerfoundation.org/winners/chaperone-assisted-protein-folding/
[7] Nature 337 (1989) 620
[8] Nature 341 (1989) 125
[9] John Ellis, Proteins as molecular chaperones, Nature 328 (1987) 378
[10] Arthur L. Horwich, Chaperonin-mediated Protein Folding, J. Biol. Chem. 288 (2013) P23622
[11] dls.nycu.edu.tw/faculty/faculty-member.html
[12] atlasgeneticsoncology.org/Genes/GC_HSPD1.html
[13] academictree.org/cellbio/peopleinfo.php?pid=57559