Harvard University scientists are a step closer to creating synthetic forms of life, part of a drive to design man-made organisms that may one day be used to help produce new fuels and create biotechnology drugs.
Researchers led by George Church, whose findings helped spur the U.S. human genome project in the 1980s, have copied the part of a living cell that makes proteins, the building blocks of life. The finding overcomes a major roadblock in making synthetic self-replicating organisms, Church said today in a lecture at Harvard in Cambridge, Massachusetts.
The technology can be used to program cells to make virtually any protein, even some that don’t exist in nature, the scientists said. That may allow production of helpful new drugs, chemicals and organisms, including living bacteria. It also opens the door to ethical concerns about creation of processes that may be uncontrollable by life’s natural defenses.
Microbes for Coal
Venter’s plan is to create man-made microbes that can help break down the coal in the earth, much as bacteria speed decomposing plant material.
In a conference for alumni today at Harvard, Church described how his team assembled a reconstituted ribosome, the first artificial version of the structure capable of remaking itself.
Naturally occurring ribosomes are used now when biotechnology companies genetically engineer cells to make the proteins for vaccines and drugs, such as Genentech Inc.’s Herceptin. Normal ribosomes make some drugs slowly, and others can’t be made at all, said Anthony Forster, a Vanderbilt University pharmacologist who has collaborated with Church on synthetic biology projects.
Efficient Protein Making
“There would be advantages to having ribosomes that would only make
specific proteins” said James Collins, a Boston University biomedical engineer, in a telephone interview. “Then you could program ribosomes so that they shut
down much of the rest of the cell, only making the proteins you want to produce.
You could shift the cell’s machinery to making certain products or fuels, for
example, and really increase efficiency.”
Specially programmed ribosomes might also have the ability to make mirror images of the active molecules in existing drugs, Church said. These mirror-image versions, sometimes called chirals, would be impervious to enzymes that the body usually uses to break down chemicals. “They would have a longer stability in natural environments,” Church said.
To reach his latest goal, Church last year hired Michael Jewett, a chemical and biological engineer who had been at Stanford University near Palo Alto, California. Jewett was one of the few people who had the knowledge of protein synthesis to move the effort forward. The project was done within a year.
“We really thought this was going to be hard, I can’t overemphasize that,” Church said. “I’m probably not articulating how exciting this is.”
Jewett quickly found ways to make and assemble the 54 proteins and three RNA molecules that go into making a ribosome. Church said he now has a “tubeful” of reconstituted ribosomes, containing millions of the artificial structures. While the findings haven’t been published, Church said they’ve been replicated many times.
Ribosomes have been synthesized before, some as long as 40 years ago. Because they were made only under specialized conditions of temperature and salt concentration, scientists couldn’t get them to recreate themselves, a key requirement in making artificial life.