LATEST UPDATES » Vol 21, No 05, May 2017 – Insights Into the Brain & microRNAs       » Omega-3 Therapy May Help Reverse Type 1 Diabetes       » The Potential of Saving Human Lives with Hibernation       » Scientists Unlock TCM Drug's Role in Weight Loss       » Medical Reforms in Beijing       » Fruits and Vegetables' Latest Superpower? Lowering Blood Pressure      
Life Under Pressure
Researchers zoom in on how biological enzymes function in extreme pressures

Washington, D.C. — Life can thrive in some of the most extreme environments on the planet. Microbes flourish inside hot geothermal vents, beneath the frigid ice covering Antarctica and under immense pressures at the bottom of the ocean. For these organisms to survive and function, so must the enzymes that enable them to live and grow. Now, researchers from Georgetown University have homed in on what allows particular enzymes to function under extreme pressures.

Enzymes are proteins that speed up critical biochemical reactions in an organism. For an enzyme to work, its molecular structure has to be stable and flexible. To facilitate a reaction, an enzyme might have to assume different shapes, known as conformations, such as an open or closed conformation — a mechanical motion that would fail if its molecular structure were too loose or too tight.

"The overall shape of the protein has to be maintained, otherwise it will unfold and do nothing, but it also needs to be flexible enough so this shape can morph into different functional conformations," said Qi Huang, a graduate student in Toshiko Ichiye's lab at Georgetown University.

Higher temperatures would loosen the atomic interactions in an enzyme, making it less stable but more flexible. High pressures would compress the enzyme and force it to become more rigid, making it more stable but less flexible. So for an enzyme under extreme conditions to function, it must adapt to have the right level of stability and flexibility. An enzyme adapted to high pressures, for example, might be more flexible than if it were adapted to normal pressures.

To better understand the effect of pressure on an enzyme — and, in particular, how it affects its flexibility — researchers led by Ichiye used computers to simulate the behavior of an enzyme at the molecular level, under various pressures and temperatures.

The researchers wanted to know which aspect of an enzyme's flexibility enables it to function under high pressures. An enzyme could be more flexible overall, like a bowl of jelly, or more flexible only at joints, like a robot. More likely, it could be flexible in both ways.

The researchers focused on a well-studied enzyme called dihydrofolate reductase, which is found in the familiar E. coli, a bacterium that lives under normal conditions, called a mesophile. They also studied a high-pressure version of the enzyme found in M. profunda, a microbe found at the bottom of the Atlantic, making it both a piezophilic (pressure-loving) organism as well as a psychrophilic (cold-loving) organism.

By comparing the two microbes, the researchers discovered that it's the collective motion involving small groups of atoms that bear on the jellylike nature of the protein that was most important. A mesophilic enzyme should work best under normal pressures while a piezophilic enzyme should work best under high pressures. The researchers found that when these enzymes worked their best, their collective motions were similar and in order for a piezophilic enzyme to adapt to high pressures, it needed to adjust its collective motion to match a mesophile's motion under normal pressure.

Understanding how these so-called extremophiles thrive helps scientists gauge under what conditions life can exist — whether it's in the ocean, deep underground, or even outer space, Huang said.

These kinds of studies could even help researchers engineer proteins from mesophilic organisms to work in extreme conditions. "We can change the DNA sequence or the amino acids of a mesophilic protein and make it function under high pressure, low or high temperatures, just like those extremophiles," Huang said. That could be useful in industrial settings, for example in making biofuels and other chemicals that require extreme conditions for optimal production. Knowing the limits of microbial life could also be useful for sterilizing and preserving food by high-pressure processing.

Source: Biophysical Society

Click here for the complete issue.

news Healthcare Sustainability in Asia: Now is the Time to Act — FT Asia Healthcare & Life Sciences Summit 2017
news Philip Morris International and British American Tobacco receive award from PETA science group for AOP developments
news 6th Asia-Pacific Breast Cancer Summit to take place in Hong Kong
Asia Pacific Biotech News

Lady Ganga: Nilza'S Story
Subscribe to APBN E-Newsletter
Find us under 'Others' option to receive APBN e-newsletters thrice a month!

APBN Editorial Calendar 2017
Healthcare Focus: LUNGS
Get to Know TCM
Diabetes: The Big Picture
The Piece of Your Mind - Brain Health/Science
Rare Diseases
Food Science & Technology
Eye Care/ Eye Health
No. 1 Killer - Heart Diseases, Diagnosis and Treatment
Skin Diseases/Allergic Reactions
Diseases threatening our Children
Liver Health & Treatment/Technology
Editorial calendar is subjected to changes.
– Editor: Carmen, Jia Wen Loh
About Us
Available issues
Editorial Board
Letters to Editor
Instructions to Authors
Advertise with Us
World Scientific Publishing Co. Pte. Ltd.
5 Toh Tuck Link, Singapore 596224
Tel: 65-6466-5775
Fax: 65-6467-7667
» For Editorial Enquiries:
   biotech_edit@wspc.com or Ms Carmen
» For Subscriptions, Advertisements &
   Media Partnerships Enquiries:
Copyright© 2017 World Scientific Publishing Co Pte Ltd  •  Privacy Policy