| Abstract Detail
Metabolism Zhang, Yi [1], Santiago, Katherine [2], Cross, Joanna [3], Sandoval, Francisco J. [4], Roje, Sanja [5]. Characterization of recombinant plastidial serine hydroxymethyltransferase from Arabidopsis. Serine hydroxymethyltransferase (SHMT) catalyzes the reversible transfer of one-carbon group from serine (Ser) to H4PteGlun, yielding glycine (Gly) and 5,10-CH2-H4PteGlun. SHMT activity has been detected in mitochondria, plastids, and the cytosol in plants. A plastidial SHMT has been purified and characterized. Mammalian SHMTs in the presence of Gly also catalyze irreversible conversion of 5,10-CH=H4PteGlun to 5-CHO-H4PteGlun. 5-CHO-H4PteGlun is not known to be a donor of one-carbon units, but is a potent inhibitor of several enzymes, including plant mitochondrial SHMT. The sensitivity of SHMTs from other subcellular compartments to this metabolite has never been investigated. The ability of plant SHMTs to catalyze conversion of 5,10-CH=H4PteGlun to the regulatory folate 5-CHO-H4PteGlun has not been investigated either, yet 5-CHO-H4PteGlun has been detected in plants. Bioinformatic evidence suggests that Arabidopsis genome encodes seven SHMTs: two appear to be localized in mitochondria, one in plastids, two in the cytosol, and two in nucleus. We here report cloning by RT-PCR, functional over-expression in E. coli, purification, and kinetic characterization of AtSHMT3. We are also determining subcellular localization of this enzyme using GFP fusion and PEG transformation of Arabidopsis protoplasts.
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1 - Washington State University, Program in Molecular Plant Sciences, Pullman, WA, 99164, USA
2 - Washington State University, Program in Molecular Plant Sciences
3 - Michigan State University, Department of Biochemistry & Molecular Biology, East Lansing, MI, 48824, U.S.A.
4 - Washington State University, Institute of Biological Chemistry, Pullman, WA, 99164, U.S.A
5 - Washington State University, Institute of Biological Chemistry, Pullman, WA, 99164, USA
Keywords:
Arabidopsis
Serine Hydroxymethyltransferase
Kinetic
GFP
Subcellular localization
protoplasts.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P19030
Abstract ID:1303 |
