Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1832526 (PCC)
 5,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of uptake of thirteen 14C-labeled amino acids were determined in nine cyanobacteria, including the unicellular strains Synechococcus sp. strain PCC 7942 and Synechocystis sp. strain PCC 6803; the filamentous strain Pseudanabaena sp. strain PCC 6903, and the filamentous, heterocyst-forming strains Anabaena sp. strains PCC 7120 and PCC 7937; Nostoc sp. strains PCC 7413 and PCC 7107; Calothrix sp. strain PCC 7601 (which is a mutant unable to develop heterocysts); and Fischerella muscicola UTEX 1829. Amino acid transport mutants, selected as mutants resistant to some amino acid analogs, were isolated from the Anabaena, Nostoc, Calothrix, and Pseudanabaena strains. All of the tested cyanobacteria bear at least a neutral amino acid transport system, and some strains also bear transport systems specific for basic or acidic amino acids. Two genes, natA and natB, encoding elements (conserved component, NatA, and periplasmic binding protein, NatB) of an ABC-type permease for neutral amino acids were identified by insertional mutagenesis of strain PCC 6803 open reading frames from the recently published genomic DNA sequence of this cyanobacterium. DNA sequences homologous to natA and natB from strain PCC 6803 were detected by hybridization in eight cyanobacterial strains tested. Mutants unable to transport neutral amino acids, including natA and natB insertional mutants, accumulated in the extracellular medium a set of amino acids that always included Ala, Val, Phe, Ile, and Leu. A general role for a cyanobacterial neutral amino acid permease in recapture of hydrophobic amino acids leaked from the cells is suggested.
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PMID:Amino acid transport in taxonomically diverse cyanobacteria and identification of two genes encoding elements of a neutral amino acid permease putatively involved in recapture of leaked hydrophobic amino acids. 900 43

Genes encoding elements of four amino acid permeases were identified by insertional inactivation of ORFs from the genomic sequence of the cyanobacterium Synechocystis sp. strain PCC 6803 whose putative products are homologous to amino acid permease proteins from other bacteria. A transport system for neutral amino acids and histidine and a transport system for basic amino acids and glutamine were identified as ABC-type transporters, whereas Na(+)-dependent transport of glutamate was found to be mediated by at least two systems, the secondary permease GltS and a TRAP-type transporter. Except for GltS, substrate specificities of the identified permeases do not match those of previously characterized systems homologous to these permeases.
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PMID:Identification of genes encoding amino acid permeases by inactivation of selected ORFs from the Synechocystis genomic sequence. 1173 93

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can fix N2 in differentiated cells called heterocysts. The products of Anabaena open reading frames (ORFs) all1046, all1047, all1284, alr1834 and all2912 were identified as putative elements of a neutral amino acid permease. Anabaena mutants of these ORFs were strongly affected (1-12% of the wild-type activity) in the transport of Pro, Phe, Leu and Gly and also impaired (17-30% of the wild-type activity) in the transport of Ala and Ser. These results identified those ORFs as the nat genes encoding the N-I neutral amino acid permease. According to amino acid sequence homologies, natA (all1046) and natE (all2912) encode ATPases, natC (all1047) and natD (all1284) encode transmembrane proteins, and natB (alr1834) encodes a periplasmic substrate-binding protein of an ABC-type uptake transporter. The natA, natC, natD and natE mutants showed defects in Gln and His uptake that were not observed in the natB mutant suggesting that NatB is not a binding protein for Gln or His. The nat mutants released hydrophobic amino acids to the medium, and amino acid release took place at higher levels in cultures incubated in the absence of combined N than in the presence of nitrate. Alanine was the amino acid released at highest levels, and its release was impaired in a mutant unable to develop heterocysts. The nat mutants were also impaired in diazotrophic growth, with natA, natC, natD and natE mutants showing more severe defects than the natB mutant. Expression of natA and natC, which constitute an operon, natCA, as well as of natB was studied and found to take place in vegetative cells but not in the heterocysts. These results indicate that the N-I permease is necessary for normal growth of Anabaena sp. strain PCC 7120 on N2, and that this permease has a role in the diazotrophic filament specifically in the vegetative cells.
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PMID:ABC-type neutral amino acid permease N-I is required for optimal diazotrophic growth and is repressed in the heterocysts of Anabaena sp. strain PCC 7120. 1613 26