University of =
Calgary=20
University of Calgary scientists discover =
'breakwater' to=20
help control electron transfer
Researchers at the University of Calgary found that amino acid =
residues form=20
a type of barrier to help in the process of electron transfer between=20
proteins.
"This raises the bar for biomolecular modeling," says Dennis Salahub, =
U of C=20
co-author of a paper published today in the prestigious journal =
Proceedings=20
of the National Academy of Sciences (PNAS). "At a fundamental level, =
it is=20
by far the most detailed insight that has been obtained for the dynamic =
role of=20
water in this kind of electron transfer, or for that matter any =
biochemical=20
reaction."
Electron transfer between proteins is the cornerstone of biological =
energy=20
transfer. Every life-form uses this process to convert food or sunlight =
into=20
chemical energy.
The interdisciplinary team of researchers found that the electron =
travels=20
over a bridge made of a water molecule, while residues on one of the =
proteins=20
form a sort of 'molecular breakwater' to keep other water molecules away =
while=20
the electron travels across the bridge.
"You don't want too many (water molecules around the bridge) because =
it gets=20
too crowded and they're all bumping into each other and you can't get =
one to fit=20
at just the right position and the right angle (for the bridge) for any =
length=20
of time," says PhD student and co-author Nathan Babcock. "It's like =
being on a=20
crowded subway where you can't get comfortable."
In artificial mutations with a faulty breakwater, the water bridge is =
disrupted and the rate of electron transfer is markedly reduced, he =
says.
Using the CHARMM molecular simulation computer program, the research =
team=20
examined a 40 nanosecond period of electronic coupling of the proteins=20
methylamine dehydrogenase and amicyanin from the bacterium Paracoccus =
denitrificans.
"This is fundamental research but you can imagine how studies like =
this can=20
be applied to various genetically modified organisms, and if you can =
gain=20
control over some, you can use it to either speed up or slow down a =
particular=20
reaction," says Salahub.
He says the work was made possible with the collaboration of two of =
the U of=20
C's interdisciplinary research institutes; the Institute for =
Biocomplexity and=20
Informatics (IBI) and the Institute for Quantum Information Science =
(IQIS).
Babcock, whose background is in quantum information theory, was =
pleased to do=20
research at the union of these two disciplines.
"When you think of quantum mechanics, usually you're thinking solid =
state=20
semi conductors, atoms trapped with lasers, etc. It's usually cold =
laboratory=20
stuff, not warm globby biological stuff," says the PhD student. "I think =
the=20
union of biology and quantum mechanics is very, very exciting."
###
"Surface residues dynamically organize water bridges to enhance =
electron=20
transfer between proteins" was published on June 14 in the journal=20
Proceedings of the National Academy of Sciences (PNAS) by Nathan =
Babcock=20
and Aurelien de la Lande, now at the CNRS in France, Jan Rezac, now at =
the Czech=20
Academy of Science, Barry Sanders, iCORE Chair of Quantum Information =
Science=20
<http://icore.ca/research_qu=
antum.htm>=20
at U of C and Dennis Salahub, Director of the Institute for =
Biocomplexity and=20
Informatics and Professor in the Department of Chemistry.