HOME >> BIOLOGY >> NEWS
Researchers discover structure of Nature's 'circuit breaker'

archaebacterium, Aeropyrum pernix, that proved more rigid and stable when isolated. They also developed a technique of attaching monoclonal antibodies to the "floppy" portions of the protein, to create attachment points for crystallization of the proteins.

The first x-ray structures using the crystals revealed a startling surprise about the voltage-dependent potassium channel, said MacKinnon. Instead of being embedded deep within the protein, the voltage-sensing gating charges appeared to be incorporated in "paddles" on the outside of the protein.

Working from the x-ray structure, the researchers theorized that these positively charged paddles would flip-flop back and forth from inside to outside the membrane, according to the charge across the membrane. When the membrane became negatively charged on the outside, the paddles would be attracted and would flip toward the outside, opening the channel and allowing potassium to flow out, restoring the membrane charge to its resting state. And when the inside of the membrane became negatively charged, the paddles would flip back, snapping the channel shut.

Indeed, in the second Nature paper, MacKinnon and his colleagues proved that the paddles actually functioned in the way suggested by the structure. In those biochemical experiments, they used antibodies and other chemicals to grab the paddles on one or the other side of the membrane, proving that they flopped back and forth with changing membrane charge.

"So, we've shown that the membrane voltage decides whether the channel's open, because the paddle feels the voltage and goes one way or the other," said MacKinnon. "It's a feedback loop. The channel sets the membrane voltage, but the membrane voltage decides whether the channel's open. This is precisely the kind of feedback loop that you need in sodium and potassium channels to propagate a nerve impulse."

MacKinnon emphasized that, although they found the paddles i
'"/>

Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
30-Apr-2003


Page: 1 2 3 4

Related biology news :

1. Researchers determine genetic cause of Timothy syndrome
2. Researchers find color sensitive atomic switch in bacteria
3. Researchers identify protein promoting vascular tumor growth
4. Researchers devise potent new tools to curb ivory poaching
5. Researchers create nanotubes that change colors, form nanocarpet and kill bacteria
6. Researchers ID chlorophyll-regulating gene
7. Researchers develop fast track way to discover how cells are regulated
8. Researchers identify distinctive signature for metastatic prostate cancer
9. Researchers report new gene test for isolated cleft lip and palate
10. Researchers discover why mutant gene causes colon cancer
11. Researchers identify the genomes controlling elements

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:5/28/2020)... ... May 27, 2020 , ... ... Workforce Advisor™ , a solution that uniquely combines lab testing insights and hc1’s ... systematically support the ongoing health and safety of employees returning to the workplace. ...
(Date:5/25/2020)... ... 2020 , ... Oxford Nanopore Technologies is in advanced development of a new ... COVID-19. , The LamPORE assay is designed to be rapid, low cost, ... numbers of samples. Hardware and reagents sit outside current, squeezed supply chains for ...
(Date:5/21/2020)... ... ... Law Enforcement has always been a highly stressful career – serving to protect, ... and women put them constantly in harm’s way both from the criminal element as ... to face very high daily stress. Now, COVID-19 introduces another even greater degree of ...
Breaking Biology News(10 mins):
(Date:6/3/2020)... (PRWEB) , ... June 03, 2020 , ... ... to highlight various applications of biofeedback. In the next installment, Dr. Inna Khazan ... practice whereby individuals learn to bring their attention to the feelings, thoughts, and ...
(Date:5/28/2020)... ... May 28, 2020 , ... Genedata, the leading provider of ... Screener ® 17.0, the latest version of its enterprise software for the automated ... Genedata will host a webinar on June 10, 2020, detailing and demonstrating the ...
(Date:5/21/2020)... ... May 19, 2020 , ... Experienced periodontist in Eden ... dental implants and bone grafting through PIEZOSURGERY® technology. PIEZOSURGERY uses ultrasonic vibrations ... used to prepare a patient for dental implants, especially when the implants need to ...
(Date:5/15/2020)... (PRWEB) , ... May 14, 2020 , ... ... to undergo multiple open heart surgeries before becoming adults. The reason: ... , To address this critical unmet need, the Department of Defense has awarded ...
Breaking Biology Technology:
Cached News: