Professor Squire Booker

Professor Squire Booker

Evan Pugh Professor of Chemistry and Molecular Biology

Eberly Family Distinguished Chair in Science

The Pennsylvania State University

Abstract

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.

Squire Booker

Professor Squire J. Booker is an Evan Pugh Professor of Chemistry and Molecular Biology, and the Eberly Family Distinguished Chair in Science at Pennsylvania State University. He is also an investigator of the Howard Hughes Medical Institute. He received a B.A. degree in chemistry from Austin College in 1987 and a Ph.D. in biochemistry from the Massachusetts Institute of Technology in 1994, where he was supervised by Prof. JoAnne Stubbe. He received and NSF-NATO postdoctoral fellowship to study at the Université René Descartes in Paris, France under the supervision of Dr. Daniel Mansuy, and then an NIH postdoctoral fellowship to study at the Institute for Enzyme Research at the University of Wisconsin under the supervision of Prof. Perry Frey. He joined the faculty at Penn State in 1999, and was promoted to Associate Professor in 2005, Professor in 2013, Eberly Family Distinguished Chair in Science in 2017, and Evan Pugh Professor in 2018.  Booker’s research focuses on the enzymology of natural product biosynthesis, with a particular interest in the methylation or sulfidation of unactivated carbon centers, and the use of S-adenosylmethionine and iron-sulfur clusters in enzyme catalysis.

 

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Start date
Thursday, April 27, 2023, 9:45 a.m.
End date
Thursday, April 27, 2023, 10:55 a.m.
Location

231 Smith Hall

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