Linked Life Data

15013767

Source:http://linkedlifedata.com/resource/pubmed/id/15013767

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-3
pubmed:dateCreated
2004-3-11
pubmed:abstractText
Flavanone 3beta-hydroxylase (FHT), a 2-oxoglutarate-dependent dioxygenase (2-ODD), catalyzes the hydroxylation of (2S)-flavanones to (2R/3R)-dihydroflavonols in plants as a key step towards the biosynthesis of flavonols, anthocyanins and catechins. Crystallographic studies of 2-ODDs typically revealed a jelly roll in the enzyme core, and the C-terminus of the enzyme polypeptides was proposed to form a lid covering the active site cavity, thereby reducing the chances for oxidative or proteolytic damage and unfolding. Moreover, it has been proposed that in some cases the C-terminus is involved in substrate selectivity of 2-ODDs. In a systematic approach with highly active Petunia FHT, four C-terminally truncated enzyme forms were generated by deletion of five, 11, 24 or 29 amino acids. The recombinant FHTs preserved their substrate selectivity, but the specific activity decreased gradually with the extent of truncation. Then, an enzyme chimera was constructed by domain swapping replacing the C-terminal 52 amino acids of Petunia FHT by the equivalent region of flavonol synthase (FLS) from Citrus unshiu, an enzyme showing ambiguous FLS and FHT activity. The chimeric dioxygenase still revealed exclusively FHT activity, albeit at a moderate level only. The data predict that the selectivity of FHT is not governed by the C-terminal sequence accounting for about 13% of the enzyme polypeptide.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
561
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
149-54
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Significance of C-terminal sequence elements for Petunia flavanone 3beta-hydroxylase activity.
pubmed:affiliation
Institut für Pharmazeutische Biologie, Philipps-Universität Marburg, Deutschhausstrasse 17 A, 35037 Marburg, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't