Crithidia fasciculata adenosine transporter 1 (CfAT1), a novel high-affinity equilibrative nucleoside transporter specific for adenosine.
Mol Biochem Parasitol
; 191(2): 75-9, 2013 Oct.
Article
em En
| MEDLINE
| ID: mdl-24120444
ABSTRACT
Most eukaryotic organisms including protozoans like Crithidia, Leishmania, and Plasmodium encode a repertoire of equilibrative nucleoside transporters (ENTs). Using genomic sequencing data from Crithidia fasciculata, we discovered that this organism contains multiple ENT genes of highly similar sequence to the previously cloned and characterized adenosine transporter CfNT1 CfAT1 and CfNT3, and an allele of CfAT1, named CfAT1.2. Characterization of CfAT1 shows that it is an adenosine-only transporter, 87% identical to CfNT1 in protein sequence, with a 50-fold lower Km for adenosine. Site directed mutation of a key residue in transmembrane domain 4 (TM4) in both CfNT1 and CfAT1 shows that lysine at this position results in a high affinity phenotype, while threonine decreases adenosine affinity in both transporters. These results show that C. fasciculata has at least two adenosine transporters, and that as in other protozoan ENTs, a lysine residue in TM4 plays a key role in ligand affinity.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Protozoários
/
Adenosina
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Crithidia fasciculata
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Proteínas de Transporte de Nucleosídeos
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Infecções por Euglenozoa
Limite:
Humans
Idioma:
En
Revista:
Mol Biochem Parasitol
Ano de publicação:
2013
Tipo de documento:
Article