UPTON, NY How much difference can a tenth of a nanometer make? When it comes to figuring out how proteins work, an improvement in resolution of that miniscule amount can mean the difference between seeing where atoms are and understanding how they interact.
Case in point: New, improved-resolution views of a zinc transporter protein deciphered at the U.S. Department of Energy's Brookhaven National Laboratory provide not just a structure but also a suggested mechanism for how cells sense and regulate zinc, an element that is essential for life, but which must be kept at a steady state to avoid problems like seizures, diabetes, and possibly Alzheimer's disease.
The new findings, to be published online on September 13, 2009, by Nature Structural & Molecular Biology, also suggest targets for zinc-regulating drugs, and may even advance the understanding of similar zinc-regulating enzymes in plant chloroplasts with possible implications for biofuel production.
"Our goal is to reveal atomic interactions in a protein structure to understand the chemistry that underlies the protein's biological function," said Brookhaven biologist Dax Fu, who led the research. "With this structure, we can begin to understand the mechanism of zinc transport at a chemical level."
The structure was revealed using x-ray crystallography at Brookhaven Lab's [http://www.nsls.bnl.gov/] National Synchrotron Light Source (NSLS), a source of intense x-ray, ultraviolet, and infrared light. By studying how x-rays bounce off crystallized samples of a protein, scientists can reconstruct the location and orientation of the protein's atoms in three dimensions.
The Brookhaven team had previously used NSLS to solve a zinc transporter protein structure at lower resolution*. To achieve the new-and-improved structure, the scientists added mercury atoms to stabilize protein packing in the crystals. This increased the re
|Contact: Karen McNulty Walsh|
DOE/Brookhaven National Laboratory