September 21, 1995-Vol27n4: Plants, animals: not so different

Plants, animals: not so different

By ELLEN GOLDBAUM

News Bureau Staff

Biochemists at UB have taken an enzyme from a bacterium found in plants and, to their surprise, genetically engineered a mutant that has an important property normally found in the animal version of the enzyme: It requires zinc instead of magnesium to function properly.

The enzyme was inserted back into the bacterium, which was introduced into soybean seedlings. The plants containing the mutant grew normally, demonstrating that the animal version could function in plants. The research was published in the Aug. 25 issue of the Journal of Biological Chemistry.

According to the authors, the research has important applications for protein engineering and research on agriculture and the environment. It also provides insight into the differences between plants and animals.

"It was very surprising that we were able to alter a fundamental property by making only a small change in the enzyme," said Mark R. O'Brian, associate professor of biochemistry at UB and lead author. UB postdoctoral researcher Sarita Chauhan was co-author. By changing just four amino acids in this 353-amino acid protein, the researchers developed a mutant enzyme that requires zinc to function.

"It was equally surprising that the enzyme functions in bacterial cells when they are put back into the plant," O'Brian said.

In making the altered enzyme, the researchers have demonstrated the potential for enzyme engineering, where scientists can design new enzymes with special properties.

O'Brian added that what may be even more illuminating is what the research contributes to knowledge about the scientific differences between plants and animals.

"It may be difficult to believe, but at the molecular level, plants and animals are more similar than they are different," said O'Brian. "That is why pesticides used to kill plants can be potentially harmful to people and animals. Defining specific molecular differences between plants and animals may aid the development of safer, more effective pesticides."

The knowledge also can be applied in phytoremediation, in which plants are used to clean up sites where soils have been contaminated with toxic levels of metals, O'Brian said. The work may also contribute toward understanding how proteins with desirable properties can be engineered for medical, agricultural and commercial uses.