Researchers have, for the first time, created detailed blueprints of
the molecular moving vans that ferry zinc everywhere
it's needed through the blood. The finding gives scientists new insights
into this important process - and a deeper understanding of the
critical role it plays in maintaining good health.
Zinc is essential for wound healing, for vision, for DNA creation,
for our senses of taste and smell, even for sexual health. But despite
its importance, scientists have never fully understood the mechanism
that moves the mineral through the body - until now.
‘Using X-ray crystallography, scientists have created colorful images of how zinc actually binds to serum albumin.’
The new work represents an international collaboration among researchers at the University of Virginia School of Medicine
and colleagues at the Universities of South Carolina (Maksymilian
Chruszcz), Warwick (Claudia A. Blindauer) and St. Andrews (Alan J.
Zinc is carried through the body by a protein known as serum
albumin. Scientists had expected there would be a primary binding site
where serum albumin binds with zinc, and the UVA researchers proved the
location of that site. But the team, led by UVA's Wladek Minor
also found several more secondary binding sites, revealing a more
complex interaction than anticipated. "It's different than it was
predicted before," said researcher Katarzyna B. Handing.
While computer models previously had been used to predict how serum
albumin picks up zinc, Minor's team used a scientific technique called
X-ray crystallography to create colorful images of zinc actually bound
to serum albumin. The technique allows them to pinpoint the location of
each particular zinc atom. It was a challenging task, but the resulting
schematics allow scientists to see, for the first time, exactly how
serum albumin and zinc come together.
A Healthy Balance
With the finding, scientists have a better grasp of how the body
maintains the delicate balances necessary for good health, a state known
as homeostasis. It's a complex dance made all the more complicated by
the fact that serum albumin also transports many other things, such as
hormones and fatty acids. "Homeostasis is extremely important, and it
can be affected by the level of zinc you are taking into your body. But
it can be also affected by other elements," Handing said. "If you have
an elevated level of fatty acids, for example as a result of diabetes or
obesity, the zinc homeostasis can be disturbed."
This is important because the body needs zinc, but too much zinc is
toxic. So the body must make it available where it is needed, but, at
the same time, it must prevent excessive buildup. If something goes
wrong with the zinc regulation process, that can have a ripple effect,
throwing the body's delicate balances out of whack and potentially
having serious effects on health.
Implications of the Discovery
Ivan G. Shabalin, a research scientist in Minor's lab, noted
that the research could help shed light on why certain drugs affect
some patients differently than others.
"We are going towards an understanding of all these complex
relationships," he said. "You have this one molecule [serum albumin],
and you have hundreds - possibly thousands - of different molecules
which bind to it. We need to understand all this interplay. By studying
zinc binding to albumin, we are understanding this relationship deeper."
The findings have been published in the scientific journal Chemical Science