科学者たちは、地球上の生命を引き起こした可能性がある「先駆者ペプチド」を識別します

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Rutgers大学の科学者たちは、30億年前に地球上で生命を始める可能性がある「ニッケルバック」というタンパク質の一部を確認しました。 この発見は、研究者が探すべき新しい手がかりを提供するので、エイリアンの生命体の探索に重要な意味があります。 研究者らは、いくつかの前駆体タンパク質がプレバイオティック化学から生きている生物学的システムへの転換に重要な役割を果たしたと信じており、「ニッケルバック」はこれらの「前駆体ペプチド」の一つである。

研究は、エイリアンの生命体の手がかりを提供することができます。

Rutgers Universityの科学者チームは、地球上の生命を初めて動力化した一連の核心化学反応である新陳代謝の原始起源を正確に見つけるために、科学者に命を生み出す直前の惑星を感知する手がかりを提供できる。タンパク質の一部を同定した。

3月10日ジャーナルに発表された研究 Center for Advanced Biotechnology and Medicine (CABM) at Rutgers.

Based on laboratory studies, Rutgers scientists say one of the most likely chemical candidates that kickstarted life was a simple peptide with two nickel atoms they are calling “Nickelback” not because it has anything to do with the Canadian rock band, but because its backbone nitrogen atoms bond two critical nickel atoms. A peptide is a constituent of a protein made up of a few elemental building blocks known as amino acids

“Scientists believe that sometime between 3.5 and 3.8 billion years ago there was a tipping point, something that kickstarted the change from prebiotic chemistry – molecules before life – to­ living, biological systems,” Nanda said. “We believe the change was sparked by a few small precursor proteins that performed key steps in an ancient metabolic reaction. And we think we’ve found one of these ‘pioneer peptides’.”

Nickelback Peptide

A computer rendering of the Nickelback peptide shows the backbone nitrogen atoms (blue) that bond two critical nickel atoms (orange). Scientists who have identified this part of a protein believe it may provide clues to detecting planets on the verge of producing life. Credit: The Nanda Laboratory

The scientists conducting the study are part of a Rutgers-led team called Evolution of Nanomachines in Geospheres and Microbial Ancestors (ENIGMA), which is part of the Astrobiology program at NASA. The researchers are seeking to understand how proteins evolved to become the predominant catalyst of life on Earth.

When scouring the universe with telescopes and probes for signs of past, present or emerging life, NASA scientists look for specific “biosignatures” known to be harbingers of life. Peptides like nickelback could become the latest biosignature employed by NASA to detect planets on the verge of producing life, Nanda said.

An original instigating chemical, the researchers reasoned, would need to be simple enough to be able to assemble spontaneously in a prebiotic soup. But it would have to be sufficiently chemically active to possess the potential to take energy from the environment to drive a biochemical process.

To do so, the researchers adopted a “reductionist” approach: They started by examining existing contemporary proteins known to be associated with metabolic processes. Knowing the proteins were too complex to have emerged early on, they pared them down to their basic structure.

After sequences of experiments, researchers concluded the best candidate was Nickelback. The peptide is made of 13 amino acids and binds two nickel ions.

Nickel, they reasoned, was an abundant metal in early oceans. When bound to the peptide, the nickel atoms become potent catalysts, attracting additional protons and electrons and producing hydrogen gas. Hydrogen, the researchers reasoned, was also more abundant on early Earth and would have been a critical source of energy to power metabolism.

“This is important because, while there are many theories about the origins of life, there are very few actual laboratory tests of these ideas,” Nanda said. “This work shows that, not only are simple protein metabolic enzymes possible, but that they are very stable and very active – making them a plausible starting point for life.”

Reference: “Design of a minimal di-nickel hydrogenase peptide” by Jennifer Timm, Douglas H. Pike, Joshua A. Mancini, Alexei M. Tyryshkin, Saroj Poudel, Jan A. Siess, Paul M. Molinaro, James J. McCann, Kate M. Waldie, Ronald L. Koder, Paul G. Falkowski and Vikas Nanda, 10 March 2023, Science Advances.
DOI: 10.1126/sciadv.abq1990

Other Rutgers researchers on the study include: Distinguished Professor Paul Falkowski and Jennifer Timm, a postdoctoral associate, in the Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences at the School of Environmental and Biological Sciences; Joshua Mancini, Douglas Pike, Saroj Poudel and Alexei Tyryshkin, postdoctoral associates, and doctoral student Jan Siess at the Center for Advanced Biotechnology and Medicine and in the Department of Biochemistry and Molecular Biology at Robert Wood Johnson Medical School; and Kate Waldie, an assistant professor of the Department of Chemistry and Chemical Biology at the School of Arts and Sciences.

Researchers from the City College of New York also participated in the study.

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Omori Yoshiaki

ミュージックホリック。フードエバンジェリスト。学生。認定エクスプローラー。受賞歴のあるウェブエキスパート。」

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