RUI: The Biosynthetic Incorporation and Characterization of Seleno-and Telluromethionine in Both Control and Novel Proteins

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; R o o t E n t r y F K `P: @ C o m p O b j b W o r d D o c u m e n t O b j e c t P o o l K `P: K `P: ? @ A B C D E F G H F Microsoft Word 6.0 Document MSWordDoc Word.Document.6 ; 9506296 Boles The overall goal of this project is the incorporation of unusual heavy atom containing amino acids into protein for use as diffraction labels and nuclear magnetic resonance (NMR) probes. The method of unusual amino acid incorporation is a biosynthetic one, where selenomethionine (SeMet) and telluromethionine (TeMet) are introduced in vivo during protein biosynthesis in place of wild type methionine. This introduces a selenium or tellurium atom in place of the lighter sulfur atom of methionine. The overall long term objectives of the research are, 1) to develop chemically defined bacterial growth protocols that allow maximal uptake of SeMet and TeMet into cellular protein, 2 ) purify, characterize and crystallize resultant control and novel proteins, and 3) prepare these proteins for analysis by x ray diffraction and/or NMR spectroscopy. Telluromethionine is a proposed in situ isomorphous replacement which may be capable of simplifying the phase problem of macromolecular crystallography simplifying three dimensional structure determinations. Undergraduate students will be independentl y integrated into this program at the appropriate level. Each student researcher will realize how their individual research project works collectively toward the latter objective. %%% Elucidation of the three dimensional structure of proteins is central to both our understanding of biological mechanisms as well as to the targeted design of new drugs. Currently, structural determinations must overcome two well known hurdles, firstly, the crystallization of a protein and secondly, solving the well known phase problem of protein crystallography. Crystallization is largely perceived as more art than science, thus, this P.I. is focusing on the latter problem: the phase problem. The atoms found in proteins are too light (lacking sufficient mass) to allow a satisfactory structural determination. It is the goal of this research to incorporate selenomethionine or telluromethionine into proteins via a biological mechanism, thus introducing two heavier atoms into the biological system: Selenium or Tellurium. These atoms are much heavier than the typical atoms found in proteins (carbon, nitrogen, oxygen, sulfur and hydrogen). These atoms can be exploited by two different available technologies, x ray diffraction and multi nuclear magnetic resonance spectroscopy, both of which are used in the determination of three dimensional structure and the study of enzyme function. It is hoped to introduce novel avenues in the simplification of structural determinations which may eventually lead to a better atomic level understanding of biological events. *** ; ; @ ....()()))()() Oh +' 0 $ H l S u m m a r y I n f o r m a t i o n ( D h R:\WWUSER\TEMPLATE\NORMAL.DOT marcia steinberg marcia steinberg @ " N: @ @ TP: @ v A Microsoft Word 6.0 2 ; e = e u D D D D D \ f D C p t t t t t t t #