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Biochemistry of endotoxin in Rhizobi...

Duke University.

Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A.
Author:	Karbarz, Mark Joseph.
Description:	241 p.
Notes:	Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2921.
Notes:	Supervisor: Christian R. H. Raetz.
Contained By:	Dissertation Abstracts International65-06B.
Subject:	Chemistry, Biochemistry.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3136823
ISBN:	0496840193

Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A.
Karbarz, Mark Joseph.

Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A. - 241 p.

Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2921.

Thesis (Ph.D.)--Duke University, 2004.

LpxE is a specific lipid A 1-phosphatase that belongs to a large superfamily of Mg2+-independent membrane associated phospholipid phosphatases (COG0671). This specificity diverse superfamily contains a tripartite active site motif, KXXXXXXRP-(XN = 12--54)-PSGH-(XN = 31--54 )-SRXXXXXHXXXD (where X is any residue). Purification of LpxE and subsequent site-directed mutagenesis of R133 (domain 1) and H197 (domain 3) confirms the requirement of these conserved residues for catalytic activity.

ISBN: 0496840193Subjects--Topical Terms:

226900
Chemistry, Biochemistry.

Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A.
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100 0 $a Karbarz, Mark Joseph. $3 227924
245 1 0 $a Biochemistry of endotoxin in Rhizobium leguminosarum: Characterization of a family of lipid phosphatases specific for the 1-position of lipid A.
300 $a 241 p.
500 $a Source: Dissertation Abstracts International, Volume: 65-06, Section: B, page: 2921.
500 $a Supervisor: Christian R. H. Raetz.
502 $a Thesis (Ph.D.)--Duke University, 2004.
520 # $a LpxE is a specific lipid A 1-phosphatase that belongs to a large superfamily of Mg2+-independent membrane associated phospholipid phosphatases (COG0671). This specificity diverse superfamily contains a tripartite active site motif, KXXXXXXRP-(XN = 12--54)-PSGH-(XN = 31--54 )-SRXXXXXHXXXD (where X is any residue). Purification of LpxE and subsequent site-directed mutagenesis of R133 (domain 1) and H197 (domain 3) confirms the requirement of these conserved residues for catalytic activity.
520 # $a The biosynthesis of lipid A in Rhizobium leguminosarum and Rhizobium etli requires several unique enzymes to process Kdo2-lipid IVA, a common lipid A biosynthetic intermediate. These enzymes include a 4'-phosphatase, a 1-phosphatase, a long chain acyltransferase, a mannosyl transferase, and a 3-O-deacylase. Of the structural genes required for processing Kdo2-lipid IV A, only the 1-phosphatase, and the 3-O-deacylase have remained elusive.
520 # $a The identification and purification of R. leguminosarum LpxE can be used to generate milligram quantities of defined 1-dephosphorylated lipid A substrates for further enzymatic assays. The identification of the LpxE should facilitate the reengineering of various bacterial species and allow for defined structure-function studies.
520 # $a The identification of R. leguminosarum LpxE facilitated the characterization of previously unidentified 1-phosphatases in Mesorhizobium loti, Helicobacter pylori and Francisella novicida. Expression in E. coli of lpxE orthologs found in M. loti, H. pylori and F. novicida directs the overexpression of lipid A 1-phosphatase activity.
520 # $a The lipid A structure of Mesorhizobium haukuii, an endosymbiont similar to M. loti, contains a galacturonic acid residue at the 1-position. Clustered adjacent to lpxE on the M. loti chromosome are orthologs of two enzymes involved in aminoarabinose modification of lipid A in E. coli, arnT and pmrF. We developed assays for these two glycosyltransferases that may be involved in galacturonic addition to 1-dephosophorylated Kdo 2-lipid IVA in M. loti.
520 # $a To identify the gene encoding the 1-phosphatase, cell lysates of a genomic library harbored in R. etli were screened for overexpressing activity. A single clone overexpressing 1-phosphatase activity was isolated and examined for genes encoding a hypothetical protein of potential phosphatase function. Membranes prepared from Escherichia coli cells overexpressing one such gene exhibited robust 1-phosphatase activity. Because this gene encodes the lipid A 1-phosphatase activity, it is now designated lpxE.
590 $a School code: 0066.
650 # 0 $a Chemistry, Biochemistry. $3 226900
650 # 0 $a Biology, Microbiology. $3 226920
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710 0 # $a Duke University. $3 226880
773 0 # $g 65-06B. $t Dissertation Abstracts International
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790 1 0 $a Raetz, Christian R. H., $e advisor
791 $a Ph.D.
792 $a 2004
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