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Discovery and characterization of no...

Katz, Jonathan Eric.

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Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms./
Author:	Katz, Jonathan Eric.
Description:	228 p.
Notes:	Source: Dissertation Abstracts International, Volume: 64-08, Section: B, page: 3807.
Contained By:	Dissertation Abstracts International64-08B.
Subject:	Chemistry, Biochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3100686

Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms.
Katz, Jonathan Eric.

Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms. - 228 p.

Source: Dissertation Abstracts International, Volume: 64-08, Section: B, page: 3807.

Thesis (Ph.D.)--University of California, Los Angeles, 2003.

<italic>S</italic>-Adenosylmethionine (AdoMet) is a common cofactor used in enzymatic reactions which require a methyl-donor. Here I present novel methodologies for identifying and screening genes that have a high likelihood of catalyzing AdoMet dependent methyltransfer reactions. I then analyze two specific methyltransferases as well as a gene product linked to a protein repair methyltransferase.Subjects--Topical Terms:

1017722
Chemistry, Biochemistry.

Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms.
LDR:03518nmm 2200325 4500 001 1858384
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008 130614s2003 eng d
035 $a (UnM)AAI3100686
035 $a AAI3100686
040 $a UnM $c UnM
100 1 $a Katz, Jonathan Eric. $3 1946076
245 1 0 $a Discovery and characterization of novel methyltransferase reactions and pathways for the amelioration of molecular aging in microorganisms.
300 $a 228 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-08, Section: B, page: 3807.
500 $a Chair: Steven Clarke.
502 $a Thesis (Ph.D.)--University of California, Los Angeles, 2003.
520 $a <italic>S</italic>-Adenosylmethionine (AdoMet) is a common cofactor used in enzymatic reactions which require a methyl-donor. Here I present novel methodologies for identifying and screening genes that have a high likelihood of catalyzing AdoMet dependent methyltransfer reactions. I then analyze two specific methyltransferases as well as a gene product linked to a protein repair methyltransferase.
520 $a Using custom and publicly available tools, a sequence-based signature is extracted from sequences of known methyltransferases and used to generate lists of putative methyltransferases from genomic sequences. My analysis suggests that AdoMet methyltransferases make up &sim;1% of the open reading frames of the genomes examined. Having generated lists of putative methyltransferases, I describe methodologies for rapid screening and functional assignment of methyltransferases in <italic>Saccharomyces cerevisiae</italic>.
520 $a A detailed functional assignment of <italic>trans</italic>-aconitate methyltransferase (TMT1) is performed using mass spectral techniques. It is shown that 2-isopropylmalate is a major endogenous substrate and is suggestive of a general role of TMTI in methylene addition biochemistry, here with leucine biosynthesis and with the other known major substrate in yeast, <italic>trans </italic>-aconitate, a citric acid cycle derivative.
520 $a Next, the absence of the highly conserved protein <smcap>L</smcap>-isoaspartyl-O-methyltranferase (PIMT) gene is examined in <italic>S. cerevisiae</italic>. PIMT catalyses the repair of a common form of protein damage: the accumulation of isoaspartyl residues in peptide chains. I show that yeast lack a PIMT gene, lack PIMT activity and, in spite of this, also lack any significant level of isoaspartyl formation. I show that this lack of damage is apparently due to a lowered pH common in yeast growth conditions and suggest that the presence of PIMT activity might be harmful to yeast physiology by disrupting AdoMet homeostasis.
520 $a Finally, I show that the SurE gene product of prokaryotes (the reading frame of which is frequently found associated with that of PIMT) has an acid phosphatase activity. I show that the gene product in both <italic>T. maritima </italic> and <italic>P. aerophilum</italic> shows selective activity towards purine monophosphates and that the activity requires a metal cofactor. I suggest that SurE may act as a scavenging enzyme for nucleic acids thereby complementing the role of PIMT as a protein repair enzyme.
590 $a School code: 0031.
650 4 $a Chemistry, Biochemistry. $3 1017722
650 4 $a Biology, Microbiology. $3 1017734
650 4 $a Biology, Molecular. $3 1017719
690 $a 0487
690 $a 0410
690 $a 0307
710 2 0 $a University of California, Los Angeles. $3 626622
773 0 $t Dissertation Abstracts International $g 64-08B.
790 1 0 $a Clarke, Steven, $e advisor
790 $a 0031
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3100686