Over the years, a number of Weizmann Institute scientists have addressed the question of how molecules essential to life, such as proteins, have adapted to function in extreme environments.
The proteins they investigated were isolated from halophilic (salt-loving) microorganisms from the Dead Sea.
After determining the 3-D structures for several halophilic proteins, researchers were able to explain how these proteins not only cope with high salinities, but are actually "addicted" to them.
However, the alga Dunaliella salina is an organism of a different streak: it is able to grow in any salinity, from the extremes of the Dead Sea to nearly fresh water.
The uniquely salt-tolerant Dunaliella, which is commercially grown as a source of natural beta carotene, has been investigated at the Weizmann Institute for over 30 years. Yet, the secrets of its exceptionally successful adaptation to salt remained unresolved.
In a recent paper published in the Proceedings of the National Academy of Sciences, USA (PNAS), Institute scientists Prof. Ada Zamir and Dr. Lakshmanane Premkumar of the Institute's Biological Chemistry Department and Prof. Joel Sussman and Dr. Harry Greenblatt of the Structural Biology Department revealed the structural basis of a remarkably salt-tolerant Dunaliella enzyme, a carbonic anhydrase, which may hold the key.
Comparisons with known carbon anhydrases from animal sources showed that the Dunaliella enzyme shares a basic plan with its distant relatives, but with a few obvious differences. The most striking of these is in the electrical charges on the proteins' surfaces:
Charges on the salt-tolerant enzyme are uniformly negative (though not as intensely negative as those in halophilic proteins), while the surfaces of carbonic anhydrases that don't tolerate salt sport a negative/positive/ neutral mix.
This and other unique structural features may enable the algal carbonic anhydrase to be active in the presence of salt, though not dependent on it.
In a surprise twist, the researchers discovered that one other known carbonic anhydrase - found in mouse kidney - sported a similar, salt-tolerant construction.
Pondering why a structure conferring salt tolerance should evolve once in a Dead Sea organism and once in a mouse has led the researchers to some new insights into kidney physiology.
The researchers hope that the knowledge gleaned from their study of a tiny alga might provide the basis for designing new drugs that could target enzymes based on their salt tolerance.
Weizmann Institute of Science
Subscribe To SpaceDaily Express
Life Is Left Handed
Moffett Field CA (SPX) Jul 11, 2005
The dry, dusty, treeless expanse of Chile's Atacama Desert is the most lifeless spot on the face of the Earth, and that's why Alison Skelley and Richard Mathies joined a team of NASA scientists there earlier this month.
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.|