(December 2, 2010) In a study that could rewrite biology
textbooks, scientists have found the first known living organism that
incorporates arsenic into the working parts of its cells. What's more, the
arsenic replaces phosphorus, an element long thought essential for life. The
results, based on experiments at the Stanford Synchrotron Radiation
Lightsource, were published online today in Science Express.
"It seems that this
particular strain of bacteria has actually evolved in a way that it can use
arsenic instead of phosphorus to grow and produce life," said SSRL Staff
Scientist Sam Webb, who led the research at the Department of Energy's SLAC
National Accelerator Laboratory. "Given that arsenic is usually toxic,
this finding is particularly surprising."
Phosphorus forms part of the
chemical backbone of DNA and RNA, the spiraling structures that carry genetic
instructions for life. It is also a central component of ATP, which transports
the chemical energy needed for metabolism within cells. Scientists have for
decades thought that life could not survive without it.