Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Carrying calcium

Molecular simulations explain how enzymatic pumps transport calcium ions within muscle cells

The transport of ions is essential for the routine maintenance of the body. For this reason cells contain specialized enzymes that act as pumps that help ions to move around and pass through boundaries.

Now, Yuji Sugita at the RIKEN Advanced Science Institute in Wako and colleagues have used computer simulations to explain how one particularly important pump enzyme, Ca2+-ATPase, transports calcium ions in muscle cells[1].

“The calcium ion pump is an essential membrane protein that can transport Ca2+ ions across biological membranes against a large concentration gradient,” explains Sugita. “It is believed to be related to some human heart diseases because there are large concentrations of the pump in the cell membranes of the heart, and the calcium ions work as messengers in muscle cells.”

Specifically, each molecule of Ca2+-ATPase transports two calcium ions at a time from a cell’s cytoplasm into the sarcoplasmic reticulum (SR), a subcellular structure devoted to regulating calcium levels. By this method the SR releases calcium ions when muscles are contracted, then reabsorbs them when muscles are relaxed.

Previous research has shown that Ca2+-ATPase on the SR membrane functions by switching between two states. First the binding sites face outwards and have high affinity for calcium in order to ‘gather’ ions from the cytoplasm. Then they face inwards and lose their affinity, thus releasing the ions into the SR.

To investigate exactly how this switching mechanism works, Sugita and colleagues focused on the role of a glutamate called Glu771, which is often found near the calcium binding sites. Studies have shown that when Glu771 is removed by mutation the calcium pump loses all its calcium-binding ability.

The researchers ran molecular dynamics simulations for both normal and mutant versions of the calcium pump. Their results revealed that the presence of Glu771 prevents water molecules from interfering at the binding site (Fig. 1). In the Glu771 mutant, this system breaks down and the binding sites get flooded with water.

This is the first time that research has indicated a relationship between calcium binding and the shielding of water, the team notes. Sugita is hopeful that with the help of more powerful computers, he and his colleagues could soon simulate a full enzymatic cycle of the calcium pump.

“We are developing new algorithms that combine all-atom and coarse-grained models,” he says. “Using such multi-scale simulation methods, we hope to elucidate further molecular mechanisms of ion uptake by the calcium pump or other ion pumps.”

The corresponding author for this highlight is based at the Theoretical Biochemistry Laboratory, RIKEN Advanced Science Institute

Journal information

[1] Sugita, Y., Ikeguchi, M. & Toyoshima, C. Relationship between Ca2+-affinity and shielding of bulk water in the Ca2+-pump from molecular dynamics simulations. Proceedings of the National Academy of Sciences USA 107, 21465–21469 (2010).

gro-pr | Research asia research news
Further information:

More articles from Life Sciences:

nachricht Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute

nachricht 'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>