Computational Chemistry and … Evolution?

Research at Florida State University in computational chemistry has uncovered evidence that an enzyme that initiates processes involving DNA and RNA does the job via two mechanisms, one of them slower than the other.

Wei Yang is an assistant professor in FSU’s Department of Chemistry and Biochemistry and a faculty member in the university’s Institute of molecular biophysics. Working with colleagues from FSU, Duke University and Brandeis University, he recently produced remarkable computer models of an enzyme that carries the unwieldy name of inosine monophosphate dehrydrogenase, or IMPDH for short. IMPDH is responsible for initiating certain metabolic processes in DNA and RNA, enabling the biological system to reproduce quickly.

“In creating these simulations of IMPDH, we observed something that hadn’t been seen before,” Yang said. “Previously, enzymes were believed to have a single ‘pathway’ through which they deliver catalytic agents to biological cells in order to bring about metabolic changes. But with IMPDH, we determined that there was a second pathway that also was used to cause these chemical transformations. The second pathway didn’t operate as efficiently as the first one, but it was active nevertheless.”

Why would an enzyme have two pathways dedicated to the same task? Yang and his colleagues believe that the slower pathway is an evolutionary vestige left over from an ancient enzyme that evolved over eons into modern-day IMPDH.

Now, that’s a pretty cool finding. I wonder how many other enzymes that we think we know everything about have alternate mechanisms for getting things done.