Linked Life Data

20887755

Source:http://linkedlifedata.com/resource/pubmed/id/20887755

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2010-11-4
pubmed:databankReference
pubmed:abstractText
Aromatic amino acid hydroxylases (AAAH) typically use tetrahydrobiopterin (H(4)B) as the cofactor. The protozoan parasite Leishmania major requires biopterin for growth and expresses strong salvage and regeneration systems to maintain H(4)B levels. Here we explored the consequences of genetic manipulation of the sole L. major phenylalanine hydroxylase (PAH) to explore whether it could account for the Leishmania H(4)B requirement. L. major PAH resembles AAAHs of other organisms, bearing eukaryotic-type domain organization, and conservation of key catalytic residues including those implicated in pteridine binding. A pah(-) null mutant and an episomal complemented overexpressing derivative (pah-/+PAH) were readily obtained, and metabolic labeling studies established that PAH was required to hydroxylate Phe to Tyr. Neither WT nor overexpressing lines were able to hydroxylate radiolabeled tyrosine or tryptophan, nor to synthesize catecholamines. WT but not pah(-) parasites showed reactivity with an antibody to melanin when grown with l-3,4-dihydroxyphenylalanine (L-DOPA), although the reactive product is unlikely to be melanin sensu strictu. WT was auxotrophic for Phe, Trp and Tyr, suggesting that PAH activity was insufficient to meet normal Tyr requirements. However, pah(-) showed an increased sensitivity to Tyr deprivation, while the pah(-)/+PAH overexpressor showed increased survival and could be adapted to grow well without added Tyr. pah(-) showed no alterations in H(4)B-dependent differentiation, as established by in vitro metacyclogenesis, or survival in mouse or macrophage infections. Thus Leishmania PAH may mitigate but not alleviate Tyr auxotrophy, but plays no essential role in the steps of the parasite infectious cycle. These findings suggest PAH is unlikely to explain the Leishmania requirement for biopterin.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1872-9428
pubmed:author
pubmed:copyrightInfo
Copyright © 2010 Elsevier B.V. All rights reserved.
pubmed:issnType
Electronic
pubmed:volume
175
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
58-67
pubmed:dateRevised
2011-9-26
pubmed:meshHeading
pubmed-meshheading:20887755-Amino Acid Sequence, pubmed-meshheading:20887755-Animals, pubmed-meshheading:20887755-Binding Sites, pubmed-meshheading:20887755-Conserved Sequence, pubmed-meshheading:20887755-Culture Media, pubmed-meshheading:20887755-DNA, Protozoan, pubmed-meshheading:20887755-Gene Knockout Techniques, pubmed-meshheading:20887755-Genetic Complementation Test, pubmed-meshheading:20887755-Hydroxylation, pubmed-meshheading:20887755-Leishmania major, pubmed-meshheading:20887755-Leishmaniasis, Cutaneous, pubmed-meshheading:20887755-Mice, pubmed-meshheading:20887755-Microbial Viability, pubmed-meshheading:20887755-Molecular Sequence Data, pubmed-meshheading:20887755-Phenylalanine, pubmed-meshheading:20887755-Phenylalanine Hydroxylase, pubmed-meshheading:20887755-Protein Structure, Tertiary, pubmed-meshheading:20887755-Sequence Alignment, pubmed-meshheading:20887755-Sequence Analysis, DNA, pubmed-meshheading:20887755-Tryptophan, pubmed-meshheading:20887755-Tyrosine, pubmed-meshheading:20887755-Virulence
pubmed:year
2011
pubmed:articleTitle
Phenylalanine hydroxylase (PAH) from the lower eukaryote Leishmania major.
pubmed:affiliation
Department of Molecular Microbiology, Box 8230, Washington University Medicine School, 600 S. Euclid Ave., St. Louis, MO 63110, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural