{"133451":{"#nid":"133451","#data":{"type":"news","title":"On Early Earth, Iron May Have Performed Magnesium\u2019s RNA Folding Job","body":[{"value":"\u003Cp\u003EOn the periodic table of the elements, iron and magnesium are far apart. But new evidence suggests that 3 billion years ago, iron did the chemical work now done by magnesium in helping RNA fold and function properly.\u003C\/p\u003E\u003Cp\u003EThere is considerable evidence that the evolution of life passed through an early stage when RNA played a more central role before DNA and coded proteins appeared. During that time, more than 3 billion years ago, the environment lacked oxygen but had an abundance of soluble iron.\u003C\/p\u003E\u003Cp\u003EIn a new study, researchers from the Georgia Institute of Technology used experiments and numerical calculations to show that iron, in the absence of oxygen, can substitute for magnesium in RNA binding, folding and catalysis. The researchers found that RNA\u2019s shape and folding structure remained the same and its functional activity increased when magnesium was replaced by iron in an oxygen-free environment.\u003C\/p\u003E\u003Cp\u003E\u201cThe primary motivation of this work was to understand RNA in plausible early earth conditions and we found that iron could support an array of RNA structures and catalytic functions more diverse than RNA with magnesium,\u201d said \u003Ca href=\u0022http:\/\/ww2.chemistry.gatech.edu\/~williams\/\u0022\u003ELoren Williams\u003C\/a\u003E, a professor in the \u003Ca href=\u0022http:\/\/www.chemistry.gatech.edu\/\u0022\u003ESchool of Chemistry and Biochemistry at Georgia Tech\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003EThe results of the study were published online on May 31, 2012 in the journal \u003Cem\u003E\u003Ca href=\u0022http:\/\/dx.plos.org\/10.1371\/journal.pone.0038024\u0022\u003EPLoS ONE\u003C\/a\u003E\u003C\/em\u003E. The study was supported by the \u003Ca href=\u0022http:\/\/astrobiology.nasa.gov\/nai\/\u0022\u003ENASA Astrobiology Institute\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003EIn addition to Williams, \u003Ca href=\u0022http:\/\/www.biology.gatech.edu\/\u0022\u003EGeorgia Tech School of Biology\u003C\/a\u003E postdoctoral fellow Shreyas Athavale, research scientist Anton Petrov, and professors \u003Ca href=\u0022http:\/\/www.biology.gatech.edu\/people\/index.php?id=roger-wartell\u0022\u003ERoger Wartell\u003C\/a\u003E and \u003Ca href=\u0022http:\/\/www.biology.gatech.edu\/people\/index.php?id=stephen-harvey\u0022\u003EStephen Harvey\u003C\/a\u003E, and \u003Ca href=\u0022http:\/\/www.chemistry.gatech.edu\/\u0022\u003EGeorgia Tech School of Chemistry and Biochemistry\u003C\/a\u003E postdoctoral fellow Chiaolong Hsiao and professor \u003Ca href=\u0022http:\/\/www.chemistry.gatech.edu\/faculty\/Hud\u0022\u003ENicholas Hud\u003C\/a\u003E also contributed to this work.\u003C\/p\u003E\u003Cp\u003EFree oxygen gas was almost nonexistent more than 3 billion years ago in the early earth\u2019s atmosphere. When oxygen began entering the environment as a product of photosynthesis, it turned the earth\u2019s iron to rust, forming massive banded iron formations that are still mined today. The free oxygen produced by advanced organisms caused iron to be toxic, even though it was -- and still is -- a requirement for life.\u003C\/p\u003E\u003Cp\u003EThis environmental transition triggered by the introduction of free oxygen into the atmosphere would have caused a slow, but dramatic, shift in biology that required transformations in biochemical mechanisms and metabolic pathways. The current study provides evidence that this transition may have caused a shift from iron to magnesium for RNA binding, folding and catalysis processes.\u003C\/p\u003E\u003Cp\u003EThe researchers used quantum mechanical calculations, chemical footprinting and two ribozyme assays to determine that in an oxygen-free environment, iron, Fe\u003Csub\u003E2+\u003C\/sub\u003E, can be substituted for magnesium, Mg\u003Csub\u003E2+\u003C\/sub\u003E, in RNA folding and catalysis.\u003C\/p\u003E\u003Cp\u003EQuantum mechanical calculations showed that the structure of RNA was nearly identical when it included iron or magnesium. When large RNAs fold into native, stable structures, negatively charged phosphate groups are brought into close proximity. The researchers calculated one small difference between the activity of iron and magnesium structures: more charge was transferred from phosphate to iron than from phosphate to magnesium.\u003C\/p\u003E\u003Cp\u003EChemical probing under anaerobic conditions showed that iron could replace magnesium in compacting and folding large RNA structures, thus providing evidence that iron and magnesium could be nearly interchangeable in their interactions with RNA.\u003C\/p\u003E\u003Cp\u003EUnder identical anaerobic conditions, the activity of two enzymes was enhanced in the presence of iron, compared to their activity in the presence of magnesium. The initial activity of the L1 ribozyme ligase, an enzyme that glues together pieces of RNA, was 25 times higher in the presence of iron. Activity of the hammerhead ribozyme, an enzyme that cuts RNA, was three times higher in the presence of iron compared to magnesium.\u003C\/p\u003E\u003Cp\u003E\u201cThe results suggest that iron is a superior substitute for magnesium in these catalytic roles,\u201d said Williams, who is also director of the Center for Ribosomal Origins and Evolution at Georgia Tech. \u201cOur hypothesis is that RNA evolved in the presence of iron and is optimized to work with iron.\u201d\u003C\/p\u003E\u003Cp\u003EIn future studies, the researchers plan to investigate what unique functions RNA can possess with iron that are not possible with magnesium.\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis work was supported by NASA (Award No. NNA09DA78A). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of NASA.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E Georgia Institute of Technology\u003Cbr \/\u003E 75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E Atlanta, Georgia 30308 USA\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Abby Robinson (abby@innovate.gatech.edu; 404-385-3364) or John Toon (jtoon@gatech.edu; 404-894-6986)\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter: \u003C\/strong\u003EAbby Robinson\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGeorgia Tech researchers used experiments and numerical calculations to show that iron, in the absence of oxygen, can substitute for magnesium in RNA binding, folding and catalysis. The findings suggest that 3 billion years ago, on the early earth, iron did the chemical work now done by magnesium.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Georgia Tech researchers used experiments and numerical calculations to show that iron, in the absence of oxygen, can substitute for magnesium in RNA binding, folding and catalysis."}],"uid":"27206","created_gmt":"2012-05-31 18:38:39","changed_gmt":"2016-10-08 03:12:22","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2012-05-31T00:00:00-04:00","iso_date":"2012-05-31T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"133421":{"id":"133421","type":"image","title":"Loren Williams RNA and iron on early earth","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Loren Williams RNA and iron on early earth","file":{"fid":"194736","name":"williams-rna-r080_hires.jpg","image_path":"\/sites\/default\/files\/images\/williams-rna-r080_hires_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/williams-rna-r080_hires_0.jpg","mime":"image\/jpeg","size":1906992,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/williams-rna-r080_hires_0.jpg?itok=D6wGTNOw"}},"133431":{"id":"133431","type":"image","title":"Loren Williams and Jessica Bowman","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Loren Williams and Jessica Bowman","file":{"fid":"194737","name":"williams-rna-bowman-r246_hires.jpg","image_path":"\/sites\/default\/files\/images\/williams-rna-bowman-r246_hires_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/williams-rna-bowman-r246_hires_0.jpg","mime":"image\/jpeg","size":1473746,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/williams-rna-bowman-r246_hires_0.jpg?itok=ZEcqfrYb"}},"133441":{"id":"133441","type":"image","title":"Loren Williams and Shreyas Athavale","body":null,"created":"1449178659","gmt_created":"2015-12-03 21:37:39","changed":"1475894759","gmt_changed":"2016-10-08 02:45:59","alt":"Loren Williams and Shreyas Athavale","file":{"fid":"194738","name":"williams-rna-athavale_-r303_hires.jpg","image_path":"\/sites\/default\/files\/images\/williams-rna-athavale_-r303_hires_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/williams-rna-athavale_-r303_hires_0.jpg","mime":"image\/jpeg","size":1750251,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/williams-rna-athavale_-r303_hires_0.jpg?itok=F2-R_Qab"}}},"media_ids":["133421","133431","133441"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"154","name":"Environment"},{"id":"146","name":"Life Sciences and Biology"},{"id":"135","name":"Research"}],"keywords":[{"id":"4896","name":"College of Sciences"},{"id":"12661","name":"Early Earth"},{"id":"34961","name":"iron"},{"id":"10720","name":"Loren Williams"},{"id":"34971","name":"magnesium"},{"id":"4504","name":"Nicholas Hud"},{"id":"9854","name":"Origin Of Life"},{"id":"984","name":"RNA"},{"id":"20371","name":"Roger Wartell"},{"id":"166928","name":"School of Chemistry and Biochemistry"},{"id":"169519","name":"Stephen Harvey"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EAbby Robinson\u003Cbr \/\u003E Research News and Publications\u003Cbr \/\u003E \u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E 404-385-3364\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}