#  Frank H. Westheimer Prize Lecture - Professor Squire Booker (Penn State) 

 



####  calendar\_today Date and Time 

 **May 6, 2024** 

 04:15PM - 05:15PM EDT 

####  pin\_drop Location 

 **Pfizer Lecture Hall**  



 

 



 

 Title: A Radical Solution for C(sp3)–C(sp3) Bond Formation during the Biosynthesis of Macrocyclic Membrane Lipids

 Archaea synthesize isoprenoid-based ether-linked membrane lipids, which enable them to withstand

 extreme environmental conditions, such as high temperatures, high salinity, and low or high pH

 values. In some archaea, such as Methanocaldococcus jannaschii, these lipids are further modified

 by forming carbon–carbon bonds between the termini of two lipid tails within one

 glycerophospholipid to generate the macrocyclic archaeol or forming two carbon– carbon bonds

 between the termini of two lipid tails from two glycerophospholipids to generate the macrocycle

 glycerol dibiphytanyl glycerol tetraether (GDGT). GDGT contains two 40-carbon lipid chains

 (biphytanyl chains) that span both leaflets of the membrane, providing enhanced

 stability to extreme conditions. How these specialized lipids are formed has puzzled scientists for

 decades. The reaction necessitates coupling two completely inert sp3-hybridized carbon centers,

 which has not been observed in nature. Here we use X-ray crystallography, high-resolution mass

 spectrometry, chemical synthesis, and biochemical analyses to show that the gene product of mj0619

 from M. jannaschii, which encodes a radical S-adenosylmethionine enzyme, is responsible for

 biphytanyl chain formation during synthesis of both the macrocyclic archaeol and GDGT membrane

 lipids



 

 



 

 See also:- [ Frank H. Westheimer Prize Lecture ](/seminar-series/frank-h-westheimer-prize-lecture)
 
 

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