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Enzymatic and structural characteriz...

Campbell, Heidi Adams.

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Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae./
Author:	Campbell, Heidi Adams.
Description:	145 p.
Notes:	Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2649.
Contained By:	Dissertation Abstracts International64-06B.
Subject:	Chemistry, Biochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3096060

Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae.
Campbell, Heidi Adams.

Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae. - 145 p.

Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2649.

Thesis (Ph.D.)--University of Michigan, 2003.

Phosphocholine-modified teichoic acid is a defining feature of the gram-positive pathogen <italic>Streptococcus pneumoniae</italic>. This cell-surface phosphocholine is essential for normal cell division and cell death, attachment and adherence to host cells, interactions with the host immune system, and the high, natural competence for transformation that is characteristic of <italic>S. pneumoniae</italic>.Subjects--Topical Terms:

1017722
Chemistry, Biochemistry.

Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae.
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008 130614s2003 eng d
035 $a (UnM)AAI3096060
035 $a AAI3096060
040 $a UnM $c UnM
100 1 $a Campbell, Heidi Adams. $3 1946056
245 1 0 $a Enzymatic and structural characterization of choline kinase and CTP:phosphocholine cytidylyltransferase from Streptococcus pneumoniae.
300 $a 145 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-06, Section: B, page: 2649.
500 $a Chair: Claudia Kent.
502 $a Thesis (Ph.D.)--University of Michigan, 2003.
520 $a Phosphocholine-modified teichoic acid is a defining feature of the gram-positive pathogen <italic>Streptococcus pneumoniae</italic>. This cell-surface phosphocholine is essential for normal cell division and cell death, attachment and adherence to host cells, interactions with the host immune system, and the high, natural competence for transformation that is characteristic of <italic>S. pneumoniae</italic>.
520 $a This work supports the hypothesis that phosphocholine is attached to teichoic acid via a CDP-choline pathway. The first step of the pathway is conversion of choline to phosphocholine by choline kinase. Phosphocholine is next activated to CDP-choline by CTP:phosphocholine cytidylyltransferase (CCT). Finally, phosphocholine is transferred from CDP-choline to an acceptor sugar group.
520 $a The <italic>licA</italic> and <italic>licC</italic> genes from the <italic> lic1</italic> operon have been cloned, and shown to encode the choline kinase and CCT enzymes, respectively. Both proteins have been overexpressed and purified in their native forms. Choline kinase was found to be a monomer, to have a very basic pH optimum, and to catalyze formation of phosphocholine with a kcat of 147 s<super>−1</super> and KM values for choline of 570 μM and for ATP of 930 μM. It also catalyzed formation of phosphoethanolamine. CCT was found to be a monomer as well, and to catalyze turnover at the rate of 46 s<super>−1</super>, with KM values for phosphocholine of 390 μM and for CTP of 890 μM. Phosphoethanolamine could serve as a poor substrate. CCT was fully inhibitable by all tested divalent cations. IC50 values for inhibition by calcium were 300 μM for both purified recombinant and endogenous enzyme.
520 $a X-ray crystal structures have been determined for CCT in complex with each of its substrates, as well as in complex with manganese. Each binary E-S complex revealed critical binding interactions. Substrate positions suggest a movement of the phosphate group of phosphocholine during catalysis. The results with manganese indicate that metals may inhibit by masking the highly negatively charged active site pocket. Although CCT from <italic>S. pneumoniae </italic> and a model enzyme for eukaryotic CCTs share similar basic protein folds, the details of protein-substrate interactions are not similar, providing a structural example of convergent evolution, and information about a possible antibiotic target.
590 $a School code: 0127.
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 Michigan. $3 777416
773 0 $t Dissertation Abstracts International $g 64-06B.
790 1 0 $a Kent, Claudia, $e advisor
790 $a 0127
791 $a Ph.D.
792 $a 2003
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3096060