Understanding life

Blankenship unravels the mysteries of photosynthesis

Restlessness can strike anyone, even world-renowned photosynthesis researchers.

Robert Blankenship, Ph.D. (left), talks with Hai Yue, a second-year graduate student in chemistry in Arts & Sciences, in Blankenship’s lab. “Bob brings more than deep knowledge of the field,” says Christine Kirmaier, Ph.D., research associate professor of chemistry. “He brings incredible energy and enthusiasm and the ability to bring together people from a wide variety of backgrounds to work on common goals.”

Robert Blankenship, Ph.D., the Lucille P. Markey Distinguished Professor of Arts & Sciences, left his position as chair of chemistry and biochemistry at Arizona State University in 2006 to come to WUSTL after 21 years in Tempe.

“It surprised a lot of people,” Blankenship says in his biology office at McDonnell Hall. (He has a chemistry office in the Laboratory Sciences Building.) “But we had reached a point where I considered doing something else. Our kids were grown and settled in school, so we didn’t have that issue.”

One day, he opened an issue of the Chronicle of Higher Education and stared at a big ad for a position in both biology and chemistry at WUSTL.

“I said, ‘Wow, that sounds like me,'” he says. “I was very attracted by the opportunities here and particularly the chance to be a faculty member in both biology and chemistry because that’s where I’m at in my research in both disciplines.”

Blankenship advises graduate students in both departments and has set up the labs so that they do experiments in his two different laboratories. He also seeks to bring members of both departments together in various ways, most notably at a party he and his wife, Liz Dorland, host annually for personnel in both departments at their house.

“It’s become sort of a tradition in just three short years,” he says, chuckling.

‘I just can’t let go of it’

Blankenship grew up in rural southeast Nebraska and was influenced and encouraged by his mother and his high-school chemistry teacher, Niel Tubbs, to pursue chemistry. As a fresh graduate student at the University of California, Berkeley, in the early 1970s, he chose to work in biophysical chemistry, a major strength of one of the world’s best chemistry programs.

Since then, Blankenship’s drive has been understanding one of the basics of life on earth: photosynthesis, the transformation of light, carbon dioxide and water into chemical energy in plants and some bacteria. The chemical reactions leading to long-term energy storage in photosynthetic systems occur in one of the most intriguing biomachines, the membrane-bound reaction center, and an affiliated number of proteins that comprise an electron transport chain. Blankenship is seeking the identity of the molecular parameters that ensure that every photon, or light packet, absorbed by a photosynthetic system leads to stable products.

“I’ve moved around a lot in the field in terms of organisms and questions that I deal with, but I’ve always maintained a tie with photosynthesis because it is such a compelling scientific system, so complex and so important that I just can’t let go of it,” he says. “Another thing I like about it is it’s extraordinarily interdisciplinary. It’s amazing the range of science you can bring to the system to try to understand it.”

The evolution of life on earth was impacted by photosynthesis and other metabolic processes, such as nitrogen fixation. Blankenship has revealed the complex evolutionary histories of these metabolic processes in analyzing whole bacterial genomes. Combining genomic and molecular evolution techniques and biochemical analyses, he also has identified and characterized previously unknown enzyme complexes with novel activities.

A PARC on campus

This spring, Blankenship was rewarded for his expertise and achievements in photosynthesis when the U.S. Department of Energy announced that WUSTL would be home to one of 46 new multimillion-dollar Energy Frontier Research Centers (EFRC). As an EFRC, the University (specifically the Danforth Campus) received a five-year, $20 million award from the Department of Energy to establish the Photosynthetic Antenna Research Center (PARC). Research to be done at PARC will analyze energy forms based on the principles of light harvesting.

(From left) Daughter, Larissa; Robert Blankenship; son, Sam; and wife, Liz Dorland.

Blankenship, who with colleague Dewey Holten, Ph.D., professor of chemistry, spearheaded the proposal for the new center, is director; Holten is associate director. The award represents the largest such in Danforth Campus history. The center will be housed at Stephen F. and Camilla T. Brauer Hall, scheduled to open in 2010.

As director, Blankenship coordinates the efforts of 16 other principal investigators from WUSTL and around the world who will gather at WUSTL once annually at a designated date to share results and create initiatives.

PARC will explore basic science research aimed at understanding the principles of the harvesting of light and funneling of energy as applied to natural photosynthetic, biohybrid and bio-inspired antenna systems, which gather light and carry it to an organism’s reaction center, where the chemistry that creates energy takes place.

“The function of any photosynthetic organism is to store solar and chemical energy,” Blankenship says. “For that to happen, light energy from the sun has to be absorbed by the plant and taken in, and that happens in the antenna system.

“Think of it as a satellite dish,” he says. “One of the things we’re going to explore is size of the antenna in different organisms. There is some evidence for bioenergy purposes that the size of the antenna that would be best for producing ethanol or biodiesel is smaller than the natural antenna, so we’ll see if we can genetically change the size of a system’s antenna and investigate that.”

Researchers will study antenna structures and also the design of artificial antennas to someday build systems that mimic photosynthesis.

Holten and his wife, Christine Kirmaier, Ph.D., research associate professor of chemistry, have known Blankenship for 35 years and have collaborated with him since the 1980s.

Robert Blankenship

Education: B.S., chemistry, 1970, Nebraska Wesleyan University; Ph.D., chemistry, 1975, University of California, Berkeley

Family: Wife, Liz Dorland; daughter, Larissa, 27; son, Sam, 23

Hobbies: Travel, cooking, hiking and fossil collecting

Little-known fact: Appears as himself in “The Grateful Dead Movie” in a 30-second snack bar scene. He’s the one who looks like the late Jerry Garcia. “People used to tell me that all the time,” he says.

Two proud achievements: Elected to the Beatrice, Neb., Education System’s Hall of Fame, 2008; his book, “Molecular Mechanisms of Photosynthesis,” will go through a second edition soon. “It’s touched a lot of students,” he says.

“Bob Blankenship is a tremendous colleague who is extremely knowledgeable about photosynthesis, from both physical and biological perspectives,” Holten says. “He is highly regarded internationally as a top researcher in the field. We’re lucky to have him here and delighted he’s a friend and colleague.”

Kirmaier adds: “Bob brings more than deep knowledge of the field. He brings incredible energy and enthusiasm and the ability to bring together people from a wide variety of backgrounds to work on common goals.”

‘Quantum beating’

Certainly, attaining PARC ranks as one of Blankenship’s greatest career accomplishments, and it highlights his short three-year stint at WUSTL. But he has had numerous publications in that short span that have contributed much to energy studies.

In 2007, he co-authored a Nature paper that for the first time detected a “quantum beating” in a photosynthetic system. He contributed protein to a study performed by collaborators at Lawrence Berkeley National Laboratory and the University of California, Berkeley.

The protein, which comes from a photosynthetic bacterium that lives in extremely high temperatures, enabled the researchers to describe the quantum effect — occurring when light-induced excitations in the bacteriochlorophyl complex meet and interfere constructively, much like the interactions between ripples formed by throwing stones into a pond.

In 2008, he was principal investigator of a project that led to the sequencing of a rare bacterium that harvests light energy by making an even rarer form of chlorophyll, chlorophyll d. This type of chlorophyll absorbs “red edge,” near infrared long wavelength light that is invisible to the naked eye. By doing this, the cyanobacterium Acaryochloris marina competes with hardly any other plant or bacterium in the world for sunlight; as such, its genome is massive in proportion to its size, comprising 8.3 million base pairs. It is the first organism containing chlorophyll d to be sequenced. Blankenship and his collaborators continue to seek the enzyme that causes a chemical structure change to make chlorophyll d, distinguishing it from primarily chlorophyll a and b but also from nine other forms of chlorophyll.

At times, Blankenship’s research is “other worldly.” In 2007, he co-authored two papers in the journal Astrobiology detailing the kinds of clues researchers are seeking that might tell them what life might be like on extrasolar planets. He and others are studying various biosignatures found in the light spectrum leaking out to Earth to speculate what kind of photosynthesis might occur on such planets and what the extrasolar planets might look like. The plants could be as black as eggplants, he says.

“It all depends on the planet’s equivalent to our sun, the colors and intensity of light coming from it that the planet feeds off and the planet’s atmospheric chemistry,” he says.

It’s quite possible that the spectrum of light available to organisms on extrasolar planets is different from light on Earth, and thus “far out” planets’ plants would have different pigments to absorb that particular light wavelength.

Blankenship is part of a NASA working group based at the Jet Propulsion Laboratory and called the Virtual Plant Laboratory. He and other researchers are studying light coming from stars and extrasolar planets to estimate its composition.

Meanwhile, life on Earth for Blankenship will continue to involve photosynthesis and energy and collaborations.

“This (WUSTL) is a marvelous place for collaborations,” he says.